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  • Cancer Control
  • v.28; Jan-Dec 2021

Cancer Biology, Epidemiology, and Treatment in the 21st Century: Current Status and Future Challenges From a Biomedical Perspective

Patricia piña-sánchez.

1 Oncology Research Unit, Oncology Hospital, Mexican Institute of Social Security, Mexico

Antonieta Chávez-González

Martha ruiz-tachiquín, eduardo vadillo, alberto monroy-garcía, juan josé montesinos, rocío grajales.

2 Department of Medical Oncology, Oncology Hospital, Mexican Institute of Social Security, Mexico

Marcos Gutiérrez de la Barrera

3 Clinical Research Division, Oncology Hospital, Mexican Institute of Social Security, Mexico

Hector Mayani

Since the second half of the 20th century, our knowledge about the biology of cancer has made extraordinary progress. Today, we understand cancer at the genomic and epigenomic levels, and we have identified the cell that starts neoplastic transformation and characterized the mechanisms for the invasion of other tissues. This knowledge has allowed novel drugs to be designed that act on specific molecular targets, the immune system to be trained and manipulated to increase its efficiency, and ever more effective therapeutic strategies to be developed. Nevertheless, we are still far from winning the war against cancer, and thus biomedical research in oncology must continue to be a global priority. Likewise, there is a need to reduce unequal access to medical services and improve prevention programs, especially in countries with a low human development index.

Introduction

During the last one hundred years, our understanding of the biology of cancer increased in an extraordinary way. 1 - 4 Such a progress has been particularly prompted during the last few decades because of technological and conceptual progress in a variety of fields, including massive next-generation sequencing, inclusion of “omic” sciences, high-resolution microscopy, molecular immunology, flow cytometry, analysis and sequencing of individual cells, new cell culture techniques, and the development of animal models, among others. Nevertheless, there are many questions yet to be answered and many problems to be solved regarding this disease. As a consequence, oncological research must be considered imperative.

Currently, cancer is one of the illnesses that causes more deaths worldwide. 5 According to data reported in 2020 by the World Health Organization (WHO), cancer is the second cause of death throughout the world, with 10 million deaths. 6 Clearly, cancer is still a leading problem worldwide. With this in mind, the objective of this article is to present a multidisciplinary and comprehensive overview of the disease. We will begin by analyzing cancer as a process, focusing on the current state of our knowledge on 4 specific aspects of its biology. Then, we will look at cancer as a global health problem, considering some epidemiological aspects, and discussing treatment, with a special focus on novel therapies. Finally, we present our vision on some of the challenges and perspectives of cancer in the 21 st century.

The Biology of Cancer

Cancer is a disease that begins with genetic and epigenetic alterations occurring in specific cells, some of which can spread and migrate to other tissues. 4 Although the biological processes affected in carcinogenesis and the evolution of neoplasms are many and widely different, we will focus on 4 aspects that are particularly relevant in tumor biology: genomic and epigenomic alterations that lead to cell transformation, the cells where these changes occur, and the processes of invasion and metastasis that, to an important degree, determine tumor aggressiveness.

Cancer Genomics

The genomics of cancer can be defined as the study of the complete sequence of DNA and its expression in tumor cells. Evidently, this study only becomes meaningful when compared to normal cells. The sequencing of the human genome, completed in 2003, was not only groundbreaking with respect to the knowledge of our gene pool, but also changed the way we study cancer. In the post-genomic era, various worldwide endeavors, such as the Human Cancer Genome Project , the Cancer Genome ATLAS (TCGA), the International Cancer Genome Consortium, and the Pan-Cancer Analysis Working Group (PCAWG), have contributed to the characterization of thousands of primary tumors from different neoplasias, generating more than 2.5 petabytes (10 15 ) of genomic, epigenomic, and proteomic information. This has led to the building of databases and analytical tools that are available for the study of cancer from an “omic” perspective, 7 , 8 and it has helped to modify classification and treatment of various neoplasms.

Studies in the past decade, including the work by the PCAWG, have shown that cancer generally begins with a small number of driving mutations (4 or 5 mutations) in particular genes, including oncogenes and tumor-suppressor genes. Mutations in TP53, a tumor-suppressor gene, for example, are found in more than half of all cancer types as an early event, and they are a hallmark of precancerous lesions. 9 - 12 From that point on, the evolution of tumors may take decades, throughout which the mutational spectrum of tumor cells changes significantly. Mutational analysis of more than 19 000 exomes revealed a collection of genomic signatures, some associated with defects in the mechanism of DNA repair. These studies also revealed the importance of alterations in non-coding regions of DNA. Thus, for example, it has been observed that various pathways of cell proliferation and chromatin remodeling are altered by mutations in coding regions, while pathways, such as WNT and NOTCH, can be disrupted by coding and non-coding mutations. To the present date, 19 955 genes that codify for proteins and 25 511 genes for non-coding RNAs have been identified ( https://www.gencodegenes.org/human/stats.html ). Based on this genomic catalogue, the COSMIC (Catalogue Of Somatic Mutations In Cancer) repository, the most robust database to date, has registered 37 288 077 coding mutations, 19 396 fusions, 1 207 190 copy number variants, and 15 642 672 non-coding variants reported up to August 2020 (v92) ( https://cosmic-blog.sanger.ac.uk/cosmic-release-v92/ ).

The genomic approach has accelerated the development of new cancer drugs. Indeed, two of the most relevant initiatives in recent years are ATOM (Accelerating Therapeutics for Opportunities in Medicine), which groups industry, government and academia, with the objective of accelerating the identification of drugs, 13 and the Connectivity Map (CMAP), a collection of transcriptional data obtained from cell lines treated with drugs for the discovery of functional connections between genes, diseases, and drugs. The CMAP 1.0 covered 1300 small molecules and more than 6000 signatures; meanwhile, the CMAP 2.0 with L1000 assay profiled more than 1.3 million samples and approximately 400 000 signatures. 14

The genomic study of tumors has had 2 fundamental contributions. On the one hand, it has allowed the confirmation and expansion of the concept of intratumor heterogeneity 15 , 16 ; and on the other, it has given rise to new classification systems for cancer. Based on the molecular classification developed by expression profiles, together with mutational and epigenomic profiles, a variety of molecular signatures have been identified, leading to the production of various commercial multigene panels. In breast cancer, for example, different panels have been developed, such as Pam50/Prosigna , Blue Print , OncotypeDX , MammaPrint , Prosigna , Endopredict , Breast Cancer Index , Mammostrat, and IHC4 . 17

Currently, the genomic/molecular study of cancer is more closely integrated with clinical practice, from the classification of neoplasms, as in tumors of the nervous system, 18 to its use in prediction, as in breast cancer. 17 Improvement in molecular methods and techniques has allowed the use of smaller amounts of biological material, as well as paraffin-embedded samples for genomic studies, both of which provide a wealth of information. 19 In addition, non-invasive methods, such as liquid biopsies, represent a great opportunity not only for the diagnosis of cancer, but also for follow-up, especially for unresectable tumors. 20

Research for the production of genomic information on cancer is presently dominated by several consortia, which has allowed the generation of a great quantity of data. However, most of these consortia and studies are performed in countries with a high human development index (HDI), and countries with a low HDI are not well represented in these large genomic studies. This is why initiatives such as Human Heredity and Health in Africa (H3Africa) for genomic research in Africa are essential. 21 Generation of new information and technological developments, such as third-generation sequencing, will undoubtedly continue to move forward in a multidisciplinary and complex systems context. However, the existing disparities in access to genomic tools for diagnosis, prognosis, and treatment of cancer will continue to be a pressing challenge at regional and social levels.

Cancer Epigenetics

Epigenetics studies the molecular mechanisms that produce hereditable changes in gene expression, without causing alterations in the DNA sequence. Epigenetic events are of 3 types: methylation of DNA and RNA, histone modification (acetylation, methylation, and phosphorylation), and the expression of non-coding RNA. Epigenetic aberrations can drive carcinogenesis when they alter chromosome conformation and the access to transcriptional machinery and to various regulatory elements (promoters, enhancers, and anchors for interaction with chromatin, for example). These changes may activate oncogenesis and silence tumor-suppressor mechanisms when they modulate coding and non-coding sequences (such as micro-RNAs and long-RNAs). This can then lead to uncontrolled growth, as well as the invasion and metastasis of cancer cells.

While genetic mutations are stable and irreversible, epigenetic alterations are dynamic and reversible; that is, there are several epigenomes, determined by space and time, which cause heterogeneity of the “epigenetic status” of tumors during their development and make them susceptible to environmental stimuli or chemotherapeutic treatment. 22 Epigenomic variability creates differences between cells, and this creates the need to analyze cells at the individual level. In the past, epigenetic analyses measured “average states” of cell populations. These studies revealed general mechanisms, such as the role of epigenetic marks on active or repressed transcriptional states, and established maps of epigenetic composition in a variety of cell types in normal and cancerous tissue. However, these approaches are difficult to use to examine events occurring in heterogeneous cell populations or in uncommon cell types. This has led to the development of new techniques that permit marking of a sequence on the epigenome and improvement in the recovery yield of epigenetic material from individual cells. This has helped to determine changes in DNA, RNA, and histones, chromatin accessibility, and chromosome conformation in a variety of neoplasms. 23 , 24

In cancer, DNA hypomethylation occurs on a global scale, while hypermethylation occurs in specific genomic loci, associated with abnormal nucleosome positioning and chromatin modifications. This information has allowed epigenomic profiles to be established in different types of neoplasms. In turn, these profiles have served as the basis to identify new neoplasm subgroups. For example, in triple negative breast cancer (TNBC), 25 and in hepatocellular carcinoma, 26 DNA methylation profiles have helped to the identification of distinct subgroups with clinical relevance. Epigenetic approaches have also helped to the development of prognostic tests to assess the sensitivity of cancer cells to specific drugs. 27

Epigenetic traits could be used to characterize intratumoral heterogeneity and determine the relevance of such a heterogeneity in clonal evolution and sensitivity to drugs. However, it is clear that heterogeneity is not only determined by genetic and epigenetic diversity resulting from clonal evolution of tumor cells, but also by the various cell populations that form the tumor microenvironment (TME). 28 Consequently, the epigenome of cancer cells is continually remodeled throughout tumorigenesis, during resistance to the activity of drugs, and in metastasis. 29 This makes therapeutic action based on epigenomic profiles difficult, although significant advances in this area have been reported. 30

During carcinogenesis and tumor progression, epigenetic modifications are categorized by their mechanisms of regulation ( Figure 1A ) and the various levels of structural complexity ( Figure 1B ). In addition, the epigenome can be modified by environmental stimuli, stochastic events, and genetic variations that impact the phenotype ( Figure 1C ). 31 , 32 The molecules that take part in these mechanisms/events/variations are therapeutic targets of interest with potential impact on clinical practice. There are studies on a wide variety of epidrugs, either alone or in combination, which improve antitumor efficacy. 33 However, the problems with these drugs must not be underestimated. For a considerable number of epigenetic compounds still being under study, the main challenge is to translate in vitro efficacy of nanomolar (nM) concentrations into well-tolerated and efficient clinical use. 34 The mechanisms of action of epidrugs may not be sufficiently controlled and could lead to diversion of the therapeutic target. 35 It is known that certain epidrugs, such as valproic acid, produce unwanted epigenetic changes 36 ; thus the need for a well-established safety profile before these drugs can be used in clinical therapy. Finally, resistance to certain epidrugs is another relevant problem. 37 , 38

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Epigenetics of cancer. (A) Molecular mechanisms. (B) Structural hierarchy of epigenomics. (C) Factors affecting the epigenome. Modified from Refs. 31 and 32 .

As we learn about the epigenome of specific cell populations in cancer patients, a door opens to the evaluation of sensitivity tests and the search for new molecular markers for detection, prognosis, follow-up, and/or response to treatment at various levels of molecular regulation. Likewise, the horizon expands for therapeutic alternatives in oncology with the use of epidrugs, such as pharmacoepigenomic modulators for genes and key pathways, including methylation of promoters and regulation of micro-RNAs involved in chemoresponse and immune response in cancer. 39 There is no doubt that integrated approaches identifying stable pharmagenomic and epigenomic patterns and their relation with expression profiles and genetic functions will be more and more valuable in our fight against cancer.

Cancer Stem Cells

Tumors consist of different populations of neoplastic cells and a variety of elements that form part of the TME, including stromal cells and molecules of the extracellular matrix. 40 Such intratumoral heterogeneity becomes even more complex during clonal variation of transformed cells, as well as influence the elements of the TME have on these cells throughout specific times and places. 41 To explain the origin of cancer cell heterogeneity, 2 models have been put forward. The first proposes that mutations occur at random during development of the tumor in individual neoplastic cells, and this promotes the production of various tumor populations, which acquire specific growth and survival traits that lead them to evolve according to intratumor mechanisms of natural selection. 42 The second model proposes that each tumor begins as a single cell that possess 2 functional properties: it can self-renew and it can produce several types of terminal cells. As these 2 properties are characteristics of somatic stem cells, 43 the cells have been called cancer stem cells (CSCs). 44 According to this model, tumors must have a hierarchical organization, where self-renewing stem cells produce highly proliferating progenitor cells, unable to self-renew but with a high proliferation potential. The latter, in turn, give rise to terminal cells. 45 Current evidence indicates that both models may coexist in tumor progression. In agreement with this idea, new subclones could be produced as a result of a lack of genetic stability and mutational changes, in addition to the heterogeneity derived from the initial CSC and its descendants. Thus, in each tumor, a set of neoplastic cells with different genetic and epigenetic traits may be found, which would provide different phenotypic properties. 46

The CSC concept was originally presented in a model of acute myeloid leukemia. 47 The presence of CSCs was later proved in chronic myeloid leukemia, breast cancer, tumors of the central nervous system, lung cancer, colon cancer, liver cancer, prostate cancer, pancreatic cancer, melanoma, and cancer of the head and neck, amongst others. In all of these cases, detection of CSCs was based on separation of several cell populations according to expression of specific surface markers, such as CD133, CD44, CD24, CD117, and CD15. 48 It is noteworthy that in some solid tumors, and even in some hematopoietic ones, a combination of specific markers that allow the isolation of CSCs has not been found. Interestingly, in such tumors, a high percentage of cells with the capacity to start secondary tumors has been observed; thus, the terms Tumor Initiating Cells (TIC) or Leukemia Initiating Cells (LIC) have been adopted. 46

A relevant aspect of the biology of CSCs is that, just like normal stem cells, they can self-renew. Such self-renewal guarantees the maintenance or expansion of the tumor stem cell population. Another trait CSCs share with normal stem cells is their quiescence, first described in chronic myeloid leukemia. 49 The persistence of quiescent CSCs in solid tumors has been recently described in colorectal cancer, where quiescent clones can become dominant after therapy with oxaliplatin. 50 In non-hierarchical tumors, such as melanoma, the existence of slow-cycling cells that are resistant to antimitogenic agents has also been proved. 51 Such experimental evidence supports the idea that quiescent CSCs or TICs are responsible for both tumor resistance to antineoplastic drugs and clinical relapse after initial therapeutic success.

In addition to quiescence, CSCs use other mechanisms to resist the action of chemotherapeutic drugs. One of these is their increased numbers: upon diagnosis, a high number of CSCs are observed in most analyzed tumors, making treatment unable to destroy all of them. On the other hand, CSCs have a high number of molecular pumps that expulse drugs, as well as high numbers of antiapoptotic molecules. In addition, they have very efficient mechanisms to repair DNA damage. In general, these cells show changes in a variety of signaling pathways involved in proliferation, survival, differentiation, and self-renewal. It is worth highlighting that in recent years, many of these pathways have become potential therapeutic targets in the elimination of CSCs. 52 Another aspect that is highly relevant in understanding the biological behavior of CSCs is that they require a specific site for their development within the tissue where they are found that can provide whatever is needed for their survival and growth. These sites, known as niches, are made of various cells, both tumor and non-tumor, as well as a variety of non-cellular elements (extracellular matrix [ECM], soluble cytokines, ion concentration gradients, etc.), capable of regulating the physiology of CSCs in order to promote their expansion, the invasion of adjacent tissues, and metastasis. 53

It is important to consider that although a large number of surface markers have been identified that allow us to enrich and prospectively follow tumor stem cell populations, to this day there is no combination of markers that allows us to find these populations in all tumors, and it is yet unclear if all tumors present them. In this regard, it is necessary to develop new purification strategies based on the gene expression profiles of these cells, so that tumor heterogeneity is taken into account, as it is evident that a tumor can include multiple clones of CSCs that, in spite of being functional, are genetically different, and that these clones can vary throughout space (occupying different microenvironments and niches) and time (during the progression of a range of tumor stages). Such strategies, in addition to new in vitro and in vivo assays, will allow the development of new and improved CSC elimination strategies. This will certainly have an impact on the development of more efficient therapeutic alternatives.

Invasion and Metastasis

Nearly 90% of the mortality associated with cancer is related to metastasis. 54 This consists of a cascade of events ( Figure 2 ) that begins with the local invasion of a tumor into surrounding tissues, followed by intravasation of tumor cells into the blood stream or lymphatic circulation. Extravasation of neoplastic cells in areas distant from the primary tumor then leads to the formation of one or more micrometastatic lesions which subsequently proliferate to form clinically detectable lesions. 4 The cells that are able to produce metastasis must acquire migratory characteristics, which occur by a process known as epithelial–mesenchymal transition (EMT), that is, the partial loss of epithelial characteristics and the acquirement of mesenchymal traits. 55

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Invasion and metastasis cascade. Invasion and metastasis can occur early or late during tumor progression. In either case, invasion to adjacent tissues is driven by stem-like cells (cancer stem cells) that acquire the epithelial–mesenchymal transition (EMT) (1). Once they reach sites adjacent to blood vessels, tumor cells (individually or in clusters) enter the blood (2). Tumor cells in circulation can adhere to endothelium and extravasation takes place (3). Other mechanisms alternative to extravasation can exist, such as angiopelosis, in which clusters of tumor cells are internalized by the endothelium. Furthermore, at certain sites, tumor cells can obstruct microvasculature and initiate a metastatic lesion right there. Sometimes, a tumor cells that has just exit circulation goes into an MET in order to become quiescent (4). Inflammatory signals can activate quiescent metastatic cells that will proliferate and generate a clinically detectable lesion (5).

Although several of the factors involved in this process are currently known, many issues are still unsolved. For instance, it has not yet been possible to monitor in vivo the specific moment when it occurs 54 ; the microenvironmental factors of the primary tumor that promote such a transition are not known with precision; and the exact moment during tumor evolution in which one cell or a cluster of cells begin to migrate to distant areas, is also unknown. The wide range of possibilities offered by intra- and inter-tumoral heterogeneity 56 stands in the way of suggesting a generalized strategy that could resolve this complication.

It was previously believed that metastasis was only produced in late stages of tumor progression; however, recent studies indicate that EMT and metastasis can occur during the early course of the disease. In pancreatic cancer, for example, cells going through EMT are able to colonize and form metastatic lesions in the liver in the first stages of the disease. 52 , 57 Metastatic cell clusters circulating in peripheral blood (PB) are prone to generate a metastatic site, compared to individual tumor cells. 58 , 59 In this regard, novel strategies, such as the use of micro-RNAs, are being assessed in order to diminish induction of EMT. 60 It must be mentioned, however, that the metastatic process seems to be even more complex, with alternative pathways that do not involve EMT. 61 , 62

A crucial stage in the process of metastasis is the intravasation of tumor cells (alone or in clusters) towards the blood stream and/or lymphatic circulation. 63 These mechanisms are also under intensive research because blocking them could allow the control of spreading of the primary tumor. In PB or lymphatic circulation, tumor cells travel to distant parts for the potential formation of a metastatic lesion. During their journey, these cells must stand the pressure of blood flow and escape interaction with natural killer (NK) cells . 64 To avoid them, tumor cells often cover themselves with thrombocytes and also produce factors such as VEGF, angiopoietin-2, angiopoietin-4, and CCL2 that are involved in the induction of vascular permeability. 54 , 65 Neutrophils also contribute to lung metastasis in the bloodstream by secreting IL-1β and metalloproteases to facilitate extravasation of tumor cells. 64

The next step in the process of metastasis is extravasation, for which tumor cells, alone or in clusters, can use various mechanisms, including a recently described process known as angiopellosis that involves restructuring the endothelial barrier to internalize one or several cells into a tissue. 66 The study of leukocyte extravasation has contributed to a more detailed knowledge of this process, in such a way that some of the proposed strategies to avoid extravasation include the use of integrin inhibitors, molecules that are vital for rolling, adhesion, and extravasation of tumor cells. 67 , 68 Another strategy that has therapeutic potential is the use of antibodies that strengthen vascular integrity to obstruct transendothelial migration of tumor cells and aid in their destruction in PB. 69

Following extravasation, tumor cells can return to an epithelial phenotype, a process known as mesenchymal–epithelial transition and may remain inactive for several years. They do this by competing for specialized niches, like those in the bone marrow, brain, and intestinal mucosa, which provide signals through the Notch and Wnt pathways. 70 Through the action of the Wnt pathway, tumor cells enter a slow state of the cell cycle and induce the expression of molecules that inhibit the cytotoxic function of NK cells. 71 The extravasated tumor cell that is in a quiescent state must comply with 2 traits typical of stem cells: they must have the capacity to self-renew and to generate all of the cells that form the secondary tumor.

There are still several questions regarding the metastatic process. One of the persisting debates at present is if EMT is essential for metastasis or if it plays a more important role in chemoresistance. 61 , 62 It is equally important to know if there is a pattern in each tumor for the production of cells with the capacity to carry out EMT. In order to control metastasis, it is fundamental to know what triggers acquisition of the migratory phenotype and the intrinsic factors determining this transition. Furthermore, it is essential to know if mutations associated with the primary tumor or the variety of epigenetic changes are involved in this process. 55 It is clear that metastatic cells have affinity for certain tissues, depending on the nature of the primary tumor (seed and soil hypothesis). This may be caused by factors such as the location and the direction of the bloodstream or lymphatic fluid, but also by conditioning of premetastatic niches at a distance (due to the large number of soluble factors secreted by the tumor and the recruitment of cells of the immune system to those sites). 72 We have yet to identify and characterize all of the elements that participate in this process. Deciphering them will be of upmost importance from a therapeutic point of view.

Epidemiology of Cancer

Cancer is the second cause of death worldwide; today one of every 6 deaths is due to a type of cancer. According to the International Agency for Research on Cancer (IARC), in 2020 there were approximately 19.3 million new cases of cancer, and 10 million deaths by this disease, 6 while 23.8 million cases and 13.0 million deaths are projected to occur by 2030. 73 In this regard, it is clear the increasing role that environmental factors—including environmental pollutants and processed food—play as cancer inducers and promoters. 74 The types of cancer that produce the greatest numbers of cases and deaths worldwide are indicated in Table 1 . 6

Total Numbers of Cancer Cases and Deaths Worldwide in 2020 by Cancer Type (According to the Global Cancer Observatory, IARC).

Data presented on this table were obtained from Ref. 6.

As shown in Figure 3 , lung, breast, prostate, and colorectal cancer are the most common throughout the world, and they are mostly concentrated in countries of high to very high human development index (HDI). Although breast, prostate, and colorectal cancer have a high incidence, the number of deaths they cause is proportionally low, mostly reflecting the great progress made in their control. However, these data also reveal the types of cancer that require further effort in prevention, precise early detection avoiding overdiagnosis, and efficient treatment. This is the case of liver, lung, esophageal, and pancreatic cancer, where the difference between the number of cases and deaths is smaller ( Figure 3B ). Social and economic transition in several countries has had an impact on reducing the incidence of neoplasms associated with infection and simultaneously produced an increase in the types related to reproductive, dietary, and hormonal factors. 75

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Incidence and mortality for some types of cancer in the world. (A) Estimated number of cases and deaths in 2020 for the most frequent cancer types worldwide. (B) Incidence and mortality rates, normalized according to age, for the most frequent cancer types in countries with very high/& high (VH&H; blue) and/low and middle (L&M; red) Human Development Index (HDI). Data include both genders and all ages. Data according to https://gco.iarc.fr/today , as of June 10, 2021.

In the past 3 decades, cancer mortality rates have fallen in high HDI countries, with the exception of pancreatic cancer, and lung cancer in women. Nevertheless, changes in the incidence of cancer do not show the same consistency, possibly due to variables such as the possibility of early detection, exposure to risk factors, or genetic predisposition. 76 , 77 Countries such as Australia, Canada, Denmark, Ireland, New Zealand, Norway, and the United Kingdom have reported a reduction in incidence and mortality in cancer of the stomach, colon, lung, and ovary, as well as an increase in survival. 78 Changes in modifiable risk factors, such as the use of tobacco, have played an important role in prevention. In this respect, it has been estimated that decline in tobacco use can explain between 35% and 45% of the reduction in cancer mortality rates, 79 while the fall in incidence and mortality due to stomach cancer can be attributed partly to the control of Helicobacter pylori infection. 80 Another key factor in the fall of mortality rates in developed countries has been an increase in early detection as a result of screening programs, as in breast and prostate cancer, which have had their mortality rates decreased dramatically in spite of an increase in their incidence. 76

Another important improvement observed in recent decades is the increase in survival rates, particularly in high HDI countries. In the USA, for example, survival rates for patients with prostate cancer at 5 years after initial diagnosis was 28% during 1947–1951; 69% during 1975–1977, and 100% during 2003–2009. Something similar occurred with breast cancer, with a 5-year survival rate of 54% in 1947–1951, 75% in 1975–1977, and 90% in 2003–2009. 81 In the CONCORD 3 version, age-standardize 5-year survival for patients with breast cancer in the USA during 2010–2014 was 90%, and 97% for prostate cancer patients. 82 Importantly, even among high HDI countries, significant differences have been identified in survival rates, being stage of disease at diagnosis, time for access to effective treatment, and comorbidities, the main factors influencing survival in these nations. 78 Unfortunately, survival rates in low HDI countries are significantly lower due to several factors, including lack of information, deficient screening and early detection programs, limited access to treatment, and suboptimal cancer registration. 82 It should be noted that in countries with low to middle HDI, neoplasms with the greatest incidence are those affecting women (breast and cervical cancer), which reflects not only a problem with access to health services, but also a serious inequality issue that involves social, cultural, and even religious obstacles. 83

Up to 42% of incident cases and 47% of deaths by cancer in the USA are due to potentially modifiable risk factors such as use of tobacco, physical activity, diet, and infection. 84 It has been calculated that 2.4 million deaths by cancer, mostly of the lung, can be attributed to tobacco. 73 In 2020, the incidence rate of lung cancer in Western Africa was 2.2, whereas in Polynesia and Eastern Asia was 37.3 and 34.4, respectively. 6 In contrast, the global burden of cancer associated with infection was 15.4%, but in Sub-Saharan Africa it was 30%. 85 Likewise, the incidence of cervical cancer in Eastern Africa was 40.1, in contrast with the USA and Canada that have a rate of 6.2. This makes it clear that one of the challenges we face is the reduction of the risk factors that are potentially modifiable and associated with specific types of cancer.

Improvement of survival rates and its disparities worldwide are also important challenges. Five-year survival for breast cancer—diagnosed during 2010-2014— in the USA, for example, was 90%, whereas in countries like South Africa it was 40%. 82 Childhood leukemia in the USA and several European countries shows a 5-year survival of 90%, while in Latin-American countries it is 50–76%. 86 Interestingly, there are neoplasms, such as pancreatic cancer, for which there has been no significant increase in survival, which remains low (5–15%) both in developed and developing countries. 82

Although data reported on global incidence and mortality gives a general overview on the epidemiology of cancer, it is important to note that there are great differences in coverage of cancer registries worldwide. To date, only 1 out of every 3 countries reports high quality data on the incidence of cancer. 87 For the past 50 years, the IARC has supported population-based cancer registries; however, more than one-third of the countries belonging to the WHO, mainly countries of low and middle income (LMIC), have no data on more than half of the 18 indicators of sustainable development goals. 88 High quality cancer registries only cover 4% of the population in Africa, 8% in Asia, and 7% in Latin America, contrasting with 83% in the USA and Canada, and 33% in Europe. 89 In response to this situation, the Global Initiative for Cancer Registry Development was created in 2012 to generate improved infrastructure to permit greater coverage and better quality registries, especially in countries with low and middle HDI. 88 It is expected that initiatives of this sort in the coming years will allow more and better information to guide strategies for the control of cancer worldwide, especially in developing regions. This will enable survival to be measured over longer periods of time (10, 15, or 20 years), as an effective measure in the control of cancer. The WHO has established as a target for 2025 to reduce deaths by cancer and other non-transmissible diseases by 25% in the population between the ages of 30–69; such an effort requires not only effective prevention measures to reduce incidence, but also more efficient health systems to diminish mortality and increase survival. At the moment, it is an even greater challenge because of the effects of the COVID-19 pandemic which has negatively impacted cancer prevention and health services. 90

Oncologic Treatments

A general perspective.

At the beginning of the 20th century, cancer treatment, specifically treatment of solid tumors, was based fundamentally on surgical resection of tumors, which together with other methods for local control, such as cauterization, had been used since ancient times. 91 At that time, there was an ongoing burst of clinical observations along with interventions sustained on fundamental knowledge about physics, chemistry, and biology. In the final years of the 19 th century and the first half of the 20th, these technological developments gave rise to radiotherapy, hormone therapy, and chemotherapy. 92 - 94 Simultaneously, immunotherapy was also developed, although usually on a smaller scale, in light of the overwhelming progress of chemotherapy and radiotherapy. 95

Thus began the development and expansion of disciplines based on these approaches (surgery, radiotherapy, chemotherapy, hormone therapy, and immunotherapy), with their application evolving ever more rapidly up to their current uses. Today, there is a wide range of therapeutic tools for the care of cancer patients. These include elements that emerged empirically, arising from observations of their effects in various medical fields, as well as drugs that were designed to block processes and pathways that form part of the physiopathology of one or more neoplasms according to knowledge of specific molecular alterations. A classic example of the first sort of tool is mustard gas, originally used as a weapon in war, 96 but when applied for medical purposes, marked the beginning of the use of chemicals in the treatment of malignant neoplasms, that is, chemotherapy. 94 A clear example of the second case is imatinib, designed specifically to selectively inhibit a molecular alteration in chronic myeloid leukemia: the Bcr-Abl oncoprotein. 97

It is on this foundation that today the 5 areas mentioned previously coexist and complement one another. The general framework that motivates this amalgam and guides its development is precision medicine, founded on the interaction of basic and clinical science. In the forecasts for development in each of these fields, surgery is expected to continue to be the fundamental approach for primary tumors in the foreseeable future, as well as when neoplastic disease in the patient is limited, or can be limited by applying systemic or regional elements, before and/or after surgical resection, and it can be reasonably anticipated for the patient to have a significant period free from disease or even to be cured. With regards to technology, intensive exploration of robotic surgery is contemplated. 98

The technological possibilities for radiotherapy have progressed in such a way that it is now possible to radiate neoplastic tissue with an extraordinary level of precision, and therefore avoid damage to healthy tissue. 99 This allows administration of large doses of ionizing radiation in one or a few fractions, what is known as “radiosurgery.” The greatest challenges to the efficacy of this approach are related to radio-resistance in certain neoplasms. Most efforts regarding research in this field are concentrated on understanding the underlying biological mechanisms of the phenomenon and their potential control through radiosensitizers. 100

“Traditional” chemotherapy, based on the use of compounds obtained from plants and other natural products, acting in a non-specific manner on both neoplastic and healthy tissues with a high proliferation rate, continues to prevail. 101 The family of chemotherapeutic drugs currently includes alkylating agents, antimetabolites, anti-topoisomerase agents, and anti-microtubules. Within the pharmacologic perspective, the objective is to attain a high concentration or activity of such molecules in specific tissues while avoiding their accumulation in others, in order to achieve an increase in effectiveness and a reduction in toxicity. This has been possible with the use of viral vectors, for example, that are able to limit their replication in neoplastic tissues, and activate prodrugs of normally nonspecific agents, like cyclophosphamide, exclusively in those specific areas. 102 More broadly, chemotherapy also includes a subgroup of substances, known as molecular targeted therapy, that affect processes in a more direct and specific manner, which will be mentioned later.

There is no doubt that immunotherapy—to be explored next—is one of the therapeutic fields where development has been greatest in recent decades and one that has produced enormous expectation in cancer treatment. 103 Likewise, cell therapy, based on the use of immune cells or stem cells, has come to complement the oncologic therapeutic arsenal. 43 Each and every one of the therapeutic fields that have arisen in oncology to this day continue to prevail and evolve. Interestingly, the foreseeable future for the development of cancer treatment contemplates these approaches in a joint and complementary manner, within the general framework of precision medicine, 104 and sustained by knowledge of the biological mechanisms involved in the appearance and progression of neoplasms. 105 , 106

Immunotherapy

Stimulating the immune system to treat cancer patients has been a historical objective in the field of oncology. Since the early work of William Coley 107 to the achievements reached at the end of the 20 th century, scientific findings and technological developments paved the way to searching for new immunotherapeutic strategies. Recombinant DNA technology allowed the synthesis of cytokines, such as interferon-alpha (IFN-α) and interleukin 2 (IL-2), which were authorized by the US Food and Drug Administration (FDA) for the treatment of hairy cell leukemia in 1986, 108 as well as kidney cancer and metastatic melanoma in 1992 and 1998, respectively. 109

The first therapeutic vaccine against cancer, based on the use of autologous dendritic cells (DCs), was approved by the FDA against prostate cancer in 2010. However, progress in the field of immunotherapy against cancer was stalled in the first decade of the present century, mostly due to failure of several vaccines in clinical trials. In many cases, application of these vaccines was detained by the complexity and cost involved in their production. Nevertheless, with the coming of the concept of immune checkpoint control, and the demonstration of the relevance of molecules such as cytotoxic T-lymphocyte antigen 4 (CTLA-4), and programmed cell death molecule-1 (PD-1), immunotherapy against cancer recovered its global relevance. In 2011, the monoclonal antibody (mAb) ipilimumab, specific to the CTLA-4 molecule, was the first checkpoint inhibitor (CPI) approved for the treatment of advanced melanoma. 110 Later, inhibitory mAbs for PD-1, or for the PD-1 ligand (PD-L1), 111 as well as the production of T cells with chimeric receptors for antigen recognition (CAR-T), 112 which have been approved to treat various types of cancer, including melanoma, non-small cell lung cancer (NSCLC), head and neck cancer, bladder cancer, renal cell carcinoma (RCC), and hepatocellular carcinoma, among others, have changed the paradigm of cancer treatment.

In spite of the current use of anti-CTLA-4 and anti-PD-L1 mAbs, only a subgroup of patients has responded favorably to these CPIs, and the number of patients achieving clinical benefit is still small. It has been estimated that more than 70% of patients with solid tumors do not respond to CPI immunotherapy because either they show primary resistance, or after responding favorably, develop resistance to treatment. 113 In this regard, it is important to mention that in recent years very important steps have been taken to identify the intrinsic and extrinsic mechanisms that mediate resistance to CPI immunotherapy. 114 Intrinsic mechanisms include changes in the antitumor immune response pathways, such as faulty processing and presentation of antigens by APCs, activation of T cells for tumor cell destruction, and changes in tumor cells that lead to an immunosuppressive TME. Extrinsic factors include the presence of immunosuppressive cells in the local TME, such as regulatory T cells, myeloid-derived suppressor cells (MDSC), mesenchymal stem/stromal cells (MSCs), and type 2 macrophages (M2), in addition to immunosuppressive cytokines.

On the other hand, classification of solid tumors as “hot,” “cold,” or “excluded,” depending on T cell infiltrates and the contact of such infiltrates with tumor cells, as well as those that present high tumor mutation burden (TMB), have redirected immunotherapy towards 3 main strategies 115 ( Table 2 ): (1) Making T-cell antitumor response more effective, using checkpoint inhibitors complementary to anti-CTLA-4 and anti-PD-L1, such as LAG3, Tim-3, and TIGT, as well as using CAR-T cells against tumor antigens. (2) Activating tumor-associated myeloid cells including monocytes, granulocytes, macrophages, and DC lineages, found at several frequencies within human solid tumors. (3) Regulating the biochemical pathways in TME that produce high concentrations of immunosuppressive molecules, such as kynurenine, a product of tryptophan metabolism, through the activity of indoleamine 2,3 dioxygenase; or adenosine, a product of ATP hydrolysis by the activity of the enzyme 5’nucleotidase (CD73). 116

Current Strategies to Stimulate the Immune Response for Antitumor Immunotherapy.

Abbreviations: TME, tumor microenvironment; IL, interleukin; TNF, Tumor Necrosis Factor; TNFR, TNF-receptor; CD137, receptor–co-stimulator of the TNFR family; OX40, member number 4 of the TNFR superfamily; CD27/CD70, member of the TNFR superfamily; CD40/CD40L, antigen-presenting cells (APC) co-stimulator and its ligand; GM-CSF, granulocyte-macrophage colony-stimulating factor; IFN, interferon; STING, IFN genes-stimulator; RIG-I, retinoic acid inducible gene-I; MDA5, melanoma differentiation-associated protein 5; CDN, cyclic dinucleotide; ATP, adenosine triphosphate; HMGB1, high mobility group B1 protein; TLR, Toll-like receptor; HVEM, Herpes virus entry mediator; GITR, glucocorticoid-induced TNFR family-related gene; CTLA4, cytotoxic T lymphocyte antigen 4; PD-L1, programmed death ligand-1; TIGIT, T-cell immunoreceptor with immunoglobulin and tyrosine-based inhibition motives; CSF1/CSF1R, colony-stimulating factor-1 and its receptor; CCR2, Type 2 chemokine receptor; PI3Kγ, Phosphoinositide 3-Kinase γ; CXCL/CCL, chemokine ligands; LFA1, lymphocyte function-associated antigen 1; ICAM1, intercellular adhesion molecule 1; VEGF, vascular endothelial growth factor; IDO, indolamine 2,3-dioxigenase; TGF, transforming growth factor; LAG-3, lymphocyte-activation gene 3 protein; TIM-3, T-cell immunoglobulin and mucin-domain containing-3; CD73, 5´nucleotidase; ARs, adenosine receptors; Selectins, cell adhesion molecules; CAR-T, chimeric antigen receptor T cell; TCR-T, T-cell receptor engineered T cell.

Apart from the problems associated with its efficacy (only a small group of patients respond to it), immunotherapy faces several challenges related to its safety. In other words, immunotherapy can induce adverse events in patients, such as autoimmunity, where healthy tissues are attacked, or cytokine release syndrome and vascular leak syndrome, as observed with the use of IL-2, both of which lead to serious hypotension, fever, renal failure, and other adverse events that are potentially lethal. The main challenges to be faced by immunotherapy in the future will require the combined efforts of basic and clinical scientists, with the objective of accelerating the understanding of the complex interactions between cancer and the immune system, and improve treatment options for patients. Better comprehension of immune phenotypes in tumors, beyond the state of PD-L1 and TME, will be relevant to increase immunotherapy efficacy. In this context, the identification of precise tumor antigenicity biomarkers by means of new technologies, such as complete genome sequencing, single cell sequencing, and epigenetic analysis to identify sites or subclones typical in drug resistance, as well as activation, traffic and infiltration of effector cells of the immune response, and regulation of TME mechanisms, may help define patient populations that are good candidates for specific therapies and therapeutic combinations. 117 , 118 Likewise, the use of agents that can induce specific activation and modulation of the response of T cells in tumor tissue, will help improve efficacy and safety profiles that can lead to better clinical results.

Molecular Targeted Therapy

For over 30 years, and based on the progress in our knowledge of tumor biology and its mechanisms, there has been a search for therapeutic alternatives that would allow spread and growth of tumors to be slowed down by blocking specific molecules. This approach is known as molecular targeted therapy. 119 Among the elements generally used as molecular targets there are transcription factors, cytokines, membrane receptors, molecules involved in a variety of signaling pathways, apoptosis modulators, promoters of angiogenesis, and cell cycle regulators. 120

Imatinib, a tyrosine kinase inhibitor for the treatment of chronic myeloid leukemia, became the first targeted therapy in the final years of the 1990s. 97 From then on, new drugs have been developed by design, and today more than 60 targeted therapies have been approved by the FDA for the treatment of a variety of cancers ( Table 3 ). 121 This has had a significant impact on progression-free survival and global survival in neoplasms such as non-small cell lung cancer, breast cancer, renal cancer, and melanoma.

FDA Approved Molecular Targeted Therapies for the Treatment of Solid Tumors.

Abbreviations: mAb, monoclonal antibody; ALK, anaplastic lymphoma kinase; CDK, cyclin-dependent kinase; CTLA-4, cytotoxic lymphocyte antigen-4; EGFR, epidermal growth factor receptor; FGFR, fibroblast growth factor receptor; GIST, gastrointestinal stroma tumor; mTOR, target of rapamycine in mammal cells; NSCLC, non-small cell lung carcinoma; PARP, poli (ADP-ribose) polimerase; PD-1, programmed death protein-1; PDGFR, platelet-derived growth factor receptor; PD-L1, programmed death ligand-1; ER, estrogen receptor; PR, progesterone receptor; TKR, tyrosine kinase receptors; SERM, selective estrogen receptor modulator; TKI, tyrosine kinase inhibitor; VEGFR, vascular endothelial growth factor receptor. Modified from Ref. [ 127 ].

Most drugs classified as targeted therapies form part of 2 large groups: small molecules and mAbs. The former are defined as compounds of low molecular weight (<900 Daltons) that act upon entering the cell. 120 Targets of these compounds are cell cycle regulatory proteins, proapoptotic proteins, or DNA repair proteins. These drugs are indicated based on histological diagnosis, as well as molecular tests. In this group there are multi-kinase inhibitors (RTKs) and tyrosine kinase inhibitors (TKIs), like sunitinib, sorafenib, and imatinib; cyclin-dependent kinase (CDK) inhibitors, such as palbociclib, ribociclib and abemaciclib; poli (ADP-ribose) polimerase inhibitors (PARPs), like olaparib and talazoparib; and selective small-molecule inhibitors, like ALK and ROS1. 122

As for mAbs, they are protein molecules that act on membrane receptors or extracellular proteins by interrupting the interaction between ligands and receptors, in such a way that they reduce cell replication and induce cytostasis. Among the most widely used mAbs in oncology we have: trastuzumab, a drug directed against the receptor for human epidermal growth factor-2 (HER2), which is overexpressed in a subgroup of patients with breast and gastric cancer; and bevacizumab, that blocks vascular endothelial growth factor and is used in patients with colorectal cancer, cervical cancer, and ovarian cancer. Other mAbs approved by the FDA include pembolizumab, atezolizumab, nivolumab, avelumab, ipilimumab, durvalumab, and cemiplimab. These drugs require expression of response biomarkers, such as PD-1 and PD-L1, and must also have several resistance biomarkers, such as the expression of EGFR, the loss of PTEN, and alterations in beta-catenin. 123

Because cancer is such a diverse disease, it is fundamental to have precise diagnostic methods that allow us to identify the most adequate therapy. Currently, basic immunohistochemistry is complemented with neoplastic molecular profiles to determine a more accurate diagnosis, and it is probable that in the near future cancer treatments will be based exclusively on molecular profiles. In this regard, it is worth mentioning that the use of targeted therapy depends on the existence of specific biomarkers that indicate if the patient will be susceptible to the effects of the drug or not. Thus, the importance of underlining that not all patients are susceptible to receive targeted therapy. In certain neoplasms, therapeutic targets are expressed in less than 5% of the diagnosed population, hindering a more extended use of certain drugs.

The identification of biomarkers and the use of new generation sequencing on tumor cells has shown predictive and prognostic relevance. Likewise, mutation analysis has allowed monitoring of tumor clone evolution, providing information on changes in canonic gene sequences, such as TP53, GATA3, PIK3CA, AKT1, and ERBB2; infrequent somatic mutations developed after primary treatments, like SWI-SNF and JAK2-STAT3; or acquired drug resistance mutations such as ESR1. 124 The study of mutations is vital; in fact, many of them already have specific therapeutic indications, which have helped select adequate treatments. 125

There is no doubt that molecular targeted therapy is one of the main pillars of precision medicine. However, it faces significant problems that often hinder obtaining better results. Among these, there is intratumor heterogeneity and differences between the primary tumor and metastatic sites, as well as intrinsic and acquired resistance to these therapies, the mechanisms of which include the presence of heterogeneous subclones, DNA hypermethylation, histone acetylation, and interruption of mRNA degradation and translation processes. 126 Nonetheless, beyond the obstacles facing molecular targeted therapy from a biological and methodological point of view, in the real world, access to genomic testing and specific drugs continues to be an enormous limitation, in such a way that strategies must be designed in the future for precision medicine to be possible on a global scale.

Cell Therapy

Another improvement in cancer treatment is the use of cell therapy, that is, the use of specific cells as therapeutic agents. This clinical procedure has 2 modalities: the first consists of replacing and regenerating functional cells in a specific tissue by means of stem/progenitor cells of a certain kind, 43 while the second uses immune cells as effectors to eliminate malignant cells. 127

Regarding the first type, we must emphasize the development of cell therapy based on hematopoietic stem and progenitor cells. 128 For over 50 years, hematopoietic cell transplants have been used to treat a variety of hematologic neoplasms (different forms of leukemia and lymphoma). Today, it is one of the most successful examples of cell therapy, including innovative modalities, such as haploidentical transplants, 129 as well as application of stem cells expanded ex vivo . 130 There are also therapies that have used immature cells that form part of the TME, such as MSCs. The replication potential and cytokine secretion capacity of these cells make them an excellent option for this type of treatment. 131 Neural stem cells can also be manipulated to produce and secrete apoptotic factors, and when these cells are incorporated into primary neural tumors, they cause a certain degree of regression. They can even be transfected with genes that encode for oncolytic enzymes capable of inducing regression of glioblastomas. 132

With respect to cell therapy using immune cells, several research groups have manipulated cells associated with tumors to make them effector cells and thus improve the efficacy and specificity of the antitumor treatment. PB leckocytes cultured in the presence of IL-2 to obtain activated lymphocytes, in combination with IL-2 administration, have been used in antitumor clinical protocols. Similarly, infiltrating lymphocytes from tumors with antitumor activity have been used and can be expanded ex vivo with IL-2. These lymphocyte populations have been used in immunomodulatory therapies in melanoma, and pancreatic and kidney tumors, producing a favorable response in treated patients. 133 NK cells and macrophages have also been used in immunotherapy, although with limited results. 134 , 135

One of the cell therapies with better projection today is the use of CAR-T cells. This strategy combines 2 forms of advanced therapy: cell therapy and gene therapy. It involves the extraction of T cells from the cancer patient, which are genetically modified in vitro to express cell surface receptors that will recognize antigens on the surface of tumor cells. The modified T cells are then reintroduced in the patient to aid in an exacerbated immune response that leads to eradication of the tumor cells ( Figure 4 ). Therapy with CAR-T cells has been used successfully in the treatment of some types of leukemia, lymphoma, and myeloma, producing complete responses in patients. 136

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CAR-T cell therapy. (A) T lymphocytes obtained from cancer patients are genetically manipulated to produce CAR-T cells that recognize tumor cells in a very specific manner. (B) Interaction between CAR molecule and tumor antigen. CAR molecule is a receptor that results from the fusion between single-chain variable fragments (scFv) from a monoclonal antibody and one or more intracellular signaling domains from the T-cell receptor. CD3ζ, CD28 and 4-1BB correspond to signaling domains on the CAR molecule.

Undoubtedly, CAR-T cell therapy has been truly efficient in the treatment of various types of neoplasms. However, this therapeutic strategy can also have serious side effects, such as release of cytokines into the bloodstream, which can cause different symptoms, from high fever to multiorgan failure, and even neurotoxicity, leading to cerebral edema in many cases. 137 Adequate control of these side effects is an important medical challenge. Several research groups are trying to improve CAR-T cell therapy through various approaches, including production of CAR-T cells directed against a wider variety of tumor cell-specific antigens that are able to attack different types of tumors, and the identification of more efficient types of T lymphocytes. Furthermore, producing CAR-T cells from a single donor that may be used in the treatment of several patients would reduce the cost of this sort of personalized cell therapy. 136

Achieving wider use of cell therapy in oncologic diseases is an important challenge that requires solving various issues. 138 One is intratumor cell heterogeneity, including malignant subclones and the various components of the TME, which results in a wide profile of membrane protein expression that complicates finding an ideal tumor antigen that allows specific identification (and elimination) of malignant cells. Likewise, structural organization of the TME challenges the use of cell therapy, as administration of cell vehicles capable of recognizing malignant cells might not be able to infiltrate the tumor. This results from low expression of chemokines in tumors and the presence of a dense fibrotic matrix that compacts the inner tumor mass and avoids antitumor cells from infiltrating and finding malignant target cells.

Further Challenges in the 21st Century

Beyond the challenges regarding oncologic biomedical research, the 21 st century is facing important issues that must be solved as soon as possible if we truly wish to gain significant ground in our fight against cancer. Three of the most important have to do with prevention, early diagnosis, and access to oncologic medication and treatment.

Prevention and Early Diagnosis

Prevention is the most cost-effective strategy in the long term, both in low and high HDI nations. Data from countries like the USA indicate that between 40-50% of all types of cancer are preventable through potentially modifiable factors (primary prevention), such as use of tobacco and alcohol, diet, physical activity, exposure to ionizing radiation, as well as prevention of infection through access to vaccination, and by reducing exposure to environmental pollutants, such as pesticides, diesel exhaust particles, solvents, etc. 74 , 84 Screening, on the other hand, has shown great effectiveness as secondary prevention. Once population-based screening programs are implemented, there is generally an initial increase in incidence; however, in the long term, a significant reduction occurs not only in incidence rates, but also in mortality rates due to detection of early lesions and timely and adequate treatment.

A good example is colon cancer. There are several options for colon cancer screening, such as detection of fecal occult blood, fecal immunohistochemistry, flexible sigmoidoscopy, and colonoscopy, 139 , 140 which identify precursor lesions (polyp adenomas) and allow their removal. Such screening has allowed us to observe 3 patterns of incidence and mortality for colon cancer between the years 2000 and 2010: on one hand, an increase in incidence and mortality in countries with low to middle HDI, mainly countries in Asia, South America, and Eastern Europe; on the other hand, an increase in incidence and a fall in mortality in countries with very high HDI, such as Canada, the United Kingdom, Denmark, and Singapore; and finally a fall in incidence and mortality in countries like the USA, Japan, and France. The situation in South America and Asia seems to reflect limitations in medical infrastructure and a lack of access to early detection, 141 while the patterns observed in developed countries reveal the success, even if it may be partial, of that which can be achieved by well-structured prevention programs.

Another example of success, but also of strong contrast, is cervical cancer. The discovery of the human papilloma virus (HPV) as the causal agent of cervical cancer brought about the development of vaccines and tests to detect oncogenic genotypes, which modified screening recommendations and guidelines, and allowed several developed countries to include the HPV vaccine in their national vaccination programs. Nevertheless, the outlook is quite different in other areas of the world. Eighty percent of the deaths by cervical cancer reported in 2018 occurred in low-income nations. This reveals the urgency of guaranteeing access to primary and secondary prevention (vaccination and screening, respectively) in these countries, or else it will continue to be a serious public health problem in spite of its preventability.

Screening programs for other neoplasms, such as breast, prostate, lung, and thyroid cancer have shown outlooks that differ from those just described, because, among other reasons, these neoplasms are highly diverse both biologically and clinically. Another relevant issue is the overdiagnosis of these neoplasms, that is, the diagnosis of disease that would not cause symptoms or death in the patient. 142 It has been calculated that 25% of breast cancer (determined by mammogram), 50–60% of prostate cancer (determined by PSA), and 13–25% of lung cancer (determined by CT) are overdiagnosed. 142 Thus, it is necessary to improve the sensitivity and specificity of screening tests. In this respect, knowledge provided by the biology of cancer and “omic” sciences offers a great opportunity to improve screening and prevention strategies. All of the above shows that prevention and early diagnosis are the foundations in the fight against cancer, and it is essential to continue to implement broader screening programs and better detection methods.

Global Equity in Oncologic Treatment

Progress in cancer treatment has considerably increased the number of cancer survivors. Nevertheless, this tendency is evident only in countries with a very solid economy. Indeed, during the past 30 years, cancer mortality rates have increased 30% worldwide. 143 Global studies indicate that close to 70% of cancer deaths in the world occur in nations of low to middle income. But even in high-income countries, there are sectors of society that are more vulnerable and have less access to cancer treatments. 144 Cancer continues to be a disease of great social inequality.

In Europe, the differences in access to cancer treatment are highly marked. These treatments are more accessible in Western Europe than in its Eastern counterpart. 145 Furthermore, highly noticeable differences between high-income countries have been detected in the cost of cancer drugs. 146 It is interesting to note that in many of these cases, treatment is too costly and the clinical benefit only marginal. Thus, the importance of these problems being approached by competent national, regional, and global authorities, because if these new drugs and therapeutic programs are not accessible to the majority, progress in biomedical, clinical and epidemiological research will have a limited impact in our fight against cancer. We must not forget that health is a universal right, from which low HDI countries must not be excluded, nor vulnerable populations in nations with high HDI. The participation of a well-informed society will also be fundamental to achieve a global impact, as today we must fight not only against the disease, but also against movements and ideas (such as the anti-vaccine movement and the so-called miracle therapies) that can block the medical battle against cancer.

Final Comments

From the second half of the 20th century to the present day, progress in our knowledge about the origin and development of cancer has been extraordinary. We now understand cancer in detail in genomic, molecular, cellular, and physiological terms, and this knowledge has had a significant impact in the clinic. There is no doubt that a patient who is diagnosed today with a type of cancer has a better prospect than a patient diagnosed 20 or 50 years ago. However, we are still far from winning the war against cancer. The challenges are still numerous. For this reason, oncologic biomedical research must be a worldwide priority. Likewise, one of the fundamental challenges for the coming decades must be to reduce unequal access to health services in areas of low- to middle income, and in populations that are especially vulnerable, as well as continue improving prevention programs, including public health programs to reduce exposure to environmental chemicals and improve diet and physical activity in the general population. 74 , 84 Fostering research and incorporation of new technological resources, particularly in less privileged nations, will play a key role in our global fight against cancer.

Declaration of Conflicting Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding: The author(s) received no financial support for the research, authorship, and/or publication of this article.

Hector Mayani https://orcid.org/0000-0002-2483-3782

Using cancer’s strength to fight against it

Dr. Jaehyuk Choi

  • Feinberg School of Medicine

Scientists at the UC San Francisco (UCSF) and Northwestern Medicine may have found a way around the limitations of engineered T cells by borrowing a few tricks from cancer itself.

By studying mutations in malignant T cells that cause lymphoma , they zeroed in on one that imparted exceptional potency to engineered T cells. Inserting a gene encoding this unique mutation into normal human T cells made them more than 100 times more potent at killing cancer cells without any signs of becoming toxic.

While current immunotherapies work only against cancers of the blood and bone marrow, the T cells engineered by Northwestern and UCSF were able to kill tumors derived from skin, lung and stomach in mice. The team has already begun working toward testing this new approach in people.

“We used nature’s roadmap to make better T cell therapies,” said Dr. Jaehyuk Choi, an associate professor of dermatology and of biochemistry and molecular genetics at Northwestern University Feinberg School of Medicine. “The superpower that makes cancer cells so strong can be transferred into T cell therapies to make them powerful enough to eliminate what were once incurable cancers.”

“Mutations underlying the resilience and adaptability of cancer cells can super-charge T cells to survive and thrive in the harsh conditions that tumors create,” said Kole Roybal, associate professor of microbiology and immunology at UCSF, center director for the Parker Institute for Cancer Immunotherapy Center at UCSF, and a member of the Gladstone Institute of Genomic Immunology.

A solution hiding in plain sight

Creating effective immunotherapies has proven difficult against most cancers because the tumor creates an environment focused on sustaining itself, redirecting resources like oxygen and nutrients for its own benefit. Often, tumors hijack the body’s immune system, causing it to defend the cancer, instead of attacking it.

Not only does this impair the ability of regular T cells to target cancer cells, it undermines the effectiveness of the engineered T cells that are used in immunotherapies, which quickly tire against the tumor’s defenses.

“For cell-based treatments to work under these conditions,” Roybal said, “we need to give healthy T cells abilities that are beyond what they can naturally achieve.”

The Northwestern and UCSF teams screened 71 mutations found in patients with T cell lymphoma and identified which ones could enhance engineered T cell therapies in mouse tumor models. Eventually, they isolated one that proved both potent and non-toxic, subjecting it to a rigorous set of safety tests.

“Our discoveries empower T cells to kill multiple cancer types,” said Choi, a member of the Robert H. Lurie Comprehensive Cancer Center of Northwestern University. “This approach performs better than anything we’ve seen before.” Their discoveries can be incorporated into treatments for many types of cancer, the scientists said. 

“T cells have the potential to offer cures to people who are heavily pretreated and have a poor prognosis,” Choi said. “Cell therapies are living drugs, because they live and grow inside the patient and can provide long-term immunity against cancer.”

In collaboration with the Parker Institute for Cancer Immunotherapy and Venrock, Roybal and Choi are building a new company, Moonlight Bio, to realize the potential of their groundbreaking approach. They are currently developing a cancer therapy that they hope to begin testing in people within the next few years.

“We see this as the starting point,” Roybal said. “There’s so much to learn from nature about how we can enhance these cells and tailor them to different types of diseases.”

Choi has affiliations with and financial interests in Moonlight Bio. Northwestern University has financial interests (equity, royalties) in Moonlight Bio.

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Stopping the cancer cells that thrive on chemotherapy – research into how pancreatic tumors adapt to stress could lead to a new treatment approach

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Postdoctoral Scholar in Pathology, University of California, San Diego

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Disclosure statement

David Cheresh receives funding from the NIH. He is a co-founder of Alpha Beta Therapeutics, Inc., a company creating new therapeutics to treat cancer, for which he also has equity and serves on the scientific advisory board.

Chengsheng Wu and Sara Weis do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.

University of California, San Diego provides funding as a member of The Conversation US.

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As with weeds in a garden, it is a challenge to fully get rid of cancer cells in the body once they arise. They have a relentless need to continuously expand, even when they are significantly cut back by therapy or surgery. Even a few cancer cells can give rise to new colonies that will eventually outgrow their borders and deplete their local resources. They also tend to wander into places where they are not welcome, creating metastatic colonies at distant sites that can be even more difficult to detect and eliminate.

One explanation for why cancer cells can withstand such inhospitable environments and growing conditions is an old adage: What doesn’t kill them makes them stronger.

At the very earliest stage of tumor formation, even before cancer can be diagnosed, individual cancer cells typically find themselves in an environment lacking nutrients, oxygen or adhesive proteins that help them attach to an area of the body to grow. While most cancer cells will quickly die when faced with such inhospitable conditions, a small percentage can adapt and gain the ability to initiate a tumor colony that will eventually become malignant disease.

We are researchers studying how these microenvironmental stresses affect tumor initiation and progression. In our new study , we found that the harsh microenvironments of the body can push certain cancer cells to overcome the stress of being isolated and make them more adept at initiating and forming new tumor colonies. Moreover, these cancer cells may adapt even better in the inhospitable and stressful conditions they encounter while trying to establish metastases in other areas of the body or after they are challenged by treatment with chemotherapy or surgery.

Cancer cells overcoming isolation stress

We focused on pancreatic cancer , one of the most lethal cancers and one that is notoriously resistant to chemotherapy and often not curable with surgery. Almost 90% of pancreatic patients will succumb to cancer recurrence or metastasis within five years after diagnosis.

We wanted to study how tumor formation is affected by what we call “ isolation stress ,” when cells are deprived of nutrients or oxygen supply because of poor blood vessel formation or because they cannot benefit from making contact with nearby cancer cells. To study how cancer cells respond to these situations, we recreated different forms of isolation stress in cell cultures, in mice and in patient samples by depriving them of oxygen and nutrients or by exposing them to chemotherapeutic drugs. We then measured which genes were turned on or off in pancreatic cancer cells.

We found that pancreatic cancer cells challenged with conditions that mimic isolation stress gain a new receptor on their surface that unstressed cancer cells don’t typically have: lysophosphatidic acid receptor 4, or LPAR4 , a protein involved in tumor progression.

When we forced the cancer cells to produce LPAR4 on their surfaces, we found that they were able to form new tumor colonies two to eight times faster than average cancer cells under isolation stress conditions. Also, preventing cancer cells from gaining LPAR4 when they were stressed reduced their ability to form tumor colonies by 80% to 95%. These findings suggest that the ability of cancer cells to gain LPAR4 when they are exposed to stress is both necessary and sufficient to promote tumor initiation.

Microscopy image of pancreatic cancer metastases arising from multiple different cell clusters

How does LPAR4 help build tumors?

We also found that LPAR4 helps cancer cells achieve tumor initiation by giving them the ability to produce a web of macromolecules, or an extracellular matrix network , that provides them an adhesive foothold within an otherwise inhospitable environment. By producing a halo of their own matrix, cancer cells with LPAR4 can start building their own tumor-supporting niche that provides a refuge from isolation stresses.

We determined that a key component of this extracellular matrix is fibronectin . When this protein binds to receptors called integrins on the surface of cells, it triggers a cascade of events that results in the expression of new genes promoting tumor initiation, stress tolerance and cancer progression. Eventually, other cancer cells are recruited into the fibronectin-rich matrix network, and a new satellite tumor colony starts to form.

Considering that tumor cells with LPAR4 can create their own tumor-supporting matrix on the fly, this suggests that LPAR4 may allow individual tumor cells to overcome isolation stress conditions and survive in the bloodstream, the lymphatic system involved in immune responses or distant organs as metastases.

Importantly, we found that isolation stress is not the only way to trigger LPAR4. Exposing pancreatic cancer cells to chemotherapy drugs, which are designed to impose stress upon cancer cells, also triggers an increase of LPAR4 on cancer cells. This finding might explain how such tumor cells could develop drug resistance.

Keeping cancer cells stressed

Understanding how to cut off the cascade of events that allows cancer cells to become stress-tolerant is important, because it provides a new area to explore for future treatments.

Our team is currently considering potential strategies to prevent cancer cells from utilizing the fibronectin matrix to gain stress tolerance, including drugs that can target the receptors that bind to fibronectin on the surface of tumor cells. One of these drugs, being developed by a company one of us co-founded, is poised to enter clinical trials soon. Other strategies include preventing cancer cells from gaining LPAR4 when they sense stress, or interfering with the signals that promote the generation of the fibronectin matrix.

For patients diagnosed with pancreatic cancer, there is a pressing need to discover how to improve the effectiveness of surgery or chemotherapy. Like combating weeds in your garden, this may require attacking the problem from multiple directions at once.

  • Chemotherapy
  • Pancreatic cancer
  • Cancer treatment
  • Tumour growth
  • Cancer cell
  • cancer recurrence
  • metastatic cancer

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Stanford Medicine scientists transform cancer cells into weapons against cancer

Researchers found that when they turned cancer cells into immune cells, they were able to teach other immune cells how to attack cancer.

March 1, 2023 - By Christopher Vaughan

Majeti

Ravi Majeti and his colleagues programmed mouse leukemia cells so that some of them could be induced to transform themselves into cells that attacked the cancer from which the cells were derived. Steve Fisch

Some cities fight gangs with ex-members who educate kids and starve gangs of new recruits. Stanford Medicine researchers have done something similar with cancer — altering cancer cells so that they teach the body’s immune system to fight the very cancer the cells came from.

“This approach could open up an entirely new therapeutic approach to treating cancer,” said Ravi Majeti , MD, PhD, a professor of hematology and the study’s senior author. The research was published March 1 in Cancer Discovery . The lead author is Miles Linde, PhD, a former PhD student in immunology who is now at the Fred Hutchinson Cancer Institute in Seattle.

Some of the most promising cancer treatments use the patient’s own immune system to attack the cancer, often by taking the brakes off immune responses to cancer or by teaching the immune system to recognize and attack the cancer more vigorously. T cells, part of the immune system that learns to identify and attack new pathogens such as viruses, can be trained to recognize specific cancer antigens, which are proteins that generate an immune response.

For instance, in CAR T-cell therapy, T cells are taken from a patient, programmed to recognize a specific cancer antigen, then returned to the patient. But there are many cancer antigens, and physicians sometimes need to guess which ones will be most potent.

Like an immune response

A better approach would be to train T cells to recognize cancer via processes that more closely mimic the way things naturally occur in the body — like the way a vaccine teaches the immune system to recognize pathogens. T cells learn to recognize pathogens because special antigen presenting cells (APCs) gather pieces of the pathogen and show them to the T cells in a way that tells the T cells, “Here is what the pathogen looks like — go get it.”

Something similar in cancer would be for APCs to gather up the many antigens that characterize a cancer cell. That way, instead of T cells being programmed to attack one or a few antigens, they are trained to recognize many cancer antigens and are more likely to wage a multipronged attack on the cancer.

Now that researchers have become adept at transforming one kind of cell into another, Majeti and his colleagues had a hunch that if they turned cancer cells into a type of APC called macrophages, they would be naturally adept at teaching T cells what to attack.

“We hypothesized that maybe cancer cells reprogrammed into macrophage cells could stimulate T cells because those APCs carry all the antigens of the cancer cells they came from,” said Majeti, who is also the RZ Cao Professor, assistant director of the Institute for Stem Cell Biology and Regenerative Medicine  and director of the Ludwig Center for Cancer Stem Cell Research and Medicine .

Cell conversion

The study builds on prior research from the Majeti lab showing that cells taken from patients with a type of acute leukemia could be converted into non-leukemic macrophages with many of the properties of APCs.

In the current study, the researchers programmed mouse leukemia cells so that some of them could be induced to transform themselves into APCs. When they tested their cancer vaccine strategy on the mouse immune system, the mice successfully cleared the cancer.

“When we first saw the data showing clearance of the leukemia in the mice with working immune systems, we were blown away,” Majeti said. “We couldn’t believe it worked as well as it did.”

Other experiments showed that the cells created from cancer cells were indeed acting as antigen-presenting cells that sensitized T cells to the cancer. “What’s more, we showed that the immune system remembered what these cells taught them,” Majeti said. “When we reintroduced cancer to these mice over 100 days after the initial tumor inoculation, they still had a strong immunological response that protected them.”

“We wondered, If this works with leukemias, will it also work with solid tumors?” Majeti said. The team tested the same approach using mouse fibrosarcoma, breast cancer, and bone cancer. “The transformation of cancer cells from solid tumors was not as efficient, but we still observed positive results,” Majeti said. With all three cancers, the creation of tumor-derived APCs led to significantly improved survival.

Lastly, the researchers returned to the original type of acute leukemia. When the human leukemia cell-derived APCs were exposed to human T cells from the same patient, they observed all the signs that would be expected if the APCs were indeed teaching the T cells how to attack the leukemia.

“We showed that reprogrammed tumor cells could lead to a durable and systemic attack on the cancer in mice and a similar response with human patient immune cells,” Majeti said. “In the future we might be able to take out tumor cells, transform them into APCs and give them back to patients as a therapeutic cancer vaccine.”

“Ultimately, we might be able to inject RNA into patients and transform enough cells to activate the immune system against cancer without having to take cells out first,” Majeti said. “That’s science fiction at this point, but that’s the direction we are interested in going.”

The work was supported by funding from the Ludwig Foundation for Cancer Research, the Emerson Collective Cancer Research Fund, the New York Stem Cell Foundation, the Stinehart-Reed Foundation, the Leukemia and Lymphoma Society, the J. Benjamin Eckenhoff Fund, the Blavatnik Family Fellowship, the Deutsche Forschungsgemainshaft, the Knut and Alice Wallenberg Foundation, the Stanford Human Biology Research Exploration Program, the National Institutes of Health (grant F31CA196029), the American Society of Hematology, the A.P. Giannini Foundation, and the Stanford Cancer Institute.

Christopher Vaughan

About Stanford Medicine

Stanford Medicine is an integrated academic health system comprising the Stanford School of Medicine and adult and pediatric health care delivery systems. Together, they harness the full potential of biomedicine through collaborative research, education and clinical care for patients. For more information, please visit med.stanford.edu .

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FDA approves groundbreaking treatment for advanced melanoma

The Food and Drug Administration on Friday approved a new cancer therapy that could one day transform the way a majority of aggressive and advanced tumors are treated.

The treatment, called Amtagvi, from Iovance Biotherapeutics , is for metastatic melanoma patients who have already tried and failed other drugs. It’s known as TIL therapy and involves boosting the number of immune cells inside tumors, harnessing their power to fight the cancer.

It’s the first time a cellular therapy has been approved to treat solid tumors. The drug was given a fast-track approval based on the results of a phase 2 clinical trial. The company is conducting a larger phase 3 trial to confirm the treatment’s benefits. The therapy’s list price — the price before insurance and other potential discounts — is $515,000 per patient. 

“This is going to be huge,” said Dr. Elizabeth Buchbinder, a senior physician at Dana-Farber Cancer Institute in Boston. Melanoma is “not one of those cancers where there’s like 20 different” possible treatments, she said. “You start running out of options fast.” 

Dan Bennett, 59, credits TIL therapy with allowing him to beat the slim odds of long-term survival of stage 4 melanoma. His daughter, Faith Bennett, 29, first noticed a suspicious mole on Bennett's neck in 2011.

Friday’s approval is only for melanoma, the deadliest form of skin cancer , but experts say it holds promise for treating other solid tumors, which account for 90% of all cancers. 

“It is our hope that future iterations of TIL therapy will be important for lung cancer, colon cancer , head and neck cancer, bladder cancer and many other cancer types,” said Dr. Patrick Hwu, chief executive of the Moffitt Cancer Center in Tampa, Florida. Moffitt has been involved with Iovance’s clinical trials of TIL therapy.

TIL stands for tumor-infiltrating lymphocytes, which are immune cells that exist within tumors . But there are nowhere nearly enough of those cells to effectively fight off cancer cells. TIL therapy involves, in part, extracting some of those immune cells from the patient’s tumor and replicating them billions of times in a lab, then reinfusing them back into the patient. 

It’s similar to CAR-T cell therapy, where healthy cells are taken out of a person’s body and then modified in a lab to fight cancers. That’s usually used for hard-to-treat blood cancers such as leukemia and lymphoma. With TIL therapy, the cells used are already programmed to recognize cancer — no lab modifications needed — they just need a boost in numbers to fight it. 

Like CAR-T, TIL therapy is a one-time treatment, though the entire process can take up to eight weeks. The TIL cells are first harvested from the tumor through a minimally invasive procedure and then grown and multiplied in the lab, a process that takes 22 days, according to Iovance. 

While that’s happening, patients are given chemotherapy to clear out their immune cells to make room for the billions of new melanoma-fighting TIL cells. Once the TIL cells are reinfused back into the body, patients get a drug called interleukin-2 to further stimulate those cells. 

Hwu said that most side effects in patients undergoing TIL therapy are not from the reinfusion of cells, but from the chemotherapy and the interleukin-2. These can include nausea and extreme fatigue, and patients are also vulnerable to other illnesses because the body is depleted of disease-fighting white blood cells. 

Putting billions of cells back into the body is not entirely risk-free, however, said Dr. William Dahut, chief scientific officer of the American Cancer Society. It’s possible that the body’s immune system could overreact in what’s known as a cytokine storm, which can cause flu-like symptoms, low blood pressure and organ damage.   “There are risks for immune-related side effects, which could be serious,” he said.

Common side effects associated with Amtagvi can include abnormally fast heart rate, fluid buildup, rash, hair loss and feeling short of breath, the FDA said.

Those side effects can be managed, said Dr. Steven Rosenberg, chief of the surgery branch at the National Cancer Institute. “They’re a small price to pay for a growing cancer that would otherwise be lethal.”

Overall, Dahut said the approval of TIL therapy is “meaningful.”

“What’s nice about this is that patients will receive a wide variety of tumor fighting lymphocytes that will be able to have the capacity to overcome resistance and actually be a living therapy over time, too, to target additional cancer cells should they develop,” Dahut said.

In addition to melanoma, Dahut said that TIL therapy is most likely to be useful in cancers that respond to drugs that “take the brakes off the immune system,” called checkpoint inhibitors .

“Those would be things like non-small cell lung cancer, kidney cancer, maybe bladder cancer, that we know are responsive to immune-based therapies to begin with,” he said. “Many of those patients relapse, so another immune-based therapy that works in a different way, seems to me, the most likely way for this to be effective.”

Much more research is needed, and it may be years before TIL therapy is approved for other types of cancer.

One of Iovance’s clinical trials investigating TIL therapy for non-small cell lung cancer was forced to pause when a participant died. While the death is under investigation, the company said it may have been the result of either chemotherapy or interleukin 2 — therapies meant to knock down each patients’ immune system before they can get the reinfusion of their TIL cells. 

The therapy is not expected to work for every metastatic melanoma patient. Clinical trial data that Iovance submitted to the FDA showed that tumors shrank in about a third of patients who received TIL therapy. 

Of those patients, about half saw their tumors shrink for at least one year, Dr. Friedrich Graf Finckenstein, chief medical officer of Iovance Biotherapeutics. “Some of these patients even had their tumor completely disappear,” he said. 

Another study, conducted in the Netherlands , did a head-to-head analysis of TIL therapy and another form of immunotherapy, called ipilimumab. Twenty percent of the patients who received TIL had complete remissions, compared with 7% of patients who got ipilimumab. Iovance was not involved with the Dutch trial.

The goal of the therapy, Hwu said, “is to get rid of the cancer and have it stay away. These immune cells stay in the body and live in the body for decades.”

The technology has been in development and studied for nearly 40 years. It was Rosenberg who pioneered TIL therapy — first describing how it could shrink melanoma tumors in the New England Journal of Medicine in 1988 .

“I’ve been waiting for a very long time to see this given to patients, because I know that it can cure some patients that have metastatic melanoma that cannot be affected by any other treatment,” Rosenberg said.

It’s worked so far for Dan Bennett, 59, of Clermont, Florida. Bennett was diagnosed with melanoma in 2011 after his daughter noticed a suspicious mole on his neck that had changed color. 

Despite surgery, chemotherapy and radiation, his cancer kept returning. In 2014, his doctors at Moffitt recommended he try TIL therapy.

“At first, we were pretty leery about it because it was unproven,” Bennett said. Ten years later, Bennett is convinced the TIL therapy is the reason he has survived so long with stage 4 melanoma, which usually has a five-year survival rate of 22.5% . 

“I would recommend any experimental drug if it’s your last opportunity,” he said. “You owe it to yourself and your family to do whatever you can to stay alive and to be a productive member of society.”

Buchbinder, the Dana-Faber doctor, was not involved with Iovance’s TIL therapy trial for melanoma, but she is scheduled to begin similar trials with other drugmakers. 

“We literally have patients right now waiting for approval because they are hoping they’ll be able to go on it,” Buchbinder said. “It is definitely a practice-changing therapy.”

research article on cancer cells

Erika Edwards is a health and medical news writer and reporter for NBC News and "TODAY."

research article on cancer cells

Anne Thompson is NBC News’ chief environmental affairs correspondent. 

Marina Kopf is an associate producer with the NBC News Health and Medical Unit.

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As cancer treatment advances, patients and doctors push back against drugs’ harsh side effects

Cancer patients and doctors have ignited a movement to radically change how new cancer drugs are tested to make them more tolerable. (Feb. 6) (AP Video by Christine Nguyen/Teresa Crawford)

Jill Feldman, 54, poses for a photo at her home in Deerfield, Ill., Friday, Jan. 19, 2024. Lung cancer patient and advocate Jill Feldman takes pills at home that shrink tumors by blocking a signal that tells cancer cells to grow. (AP Photo/Nam Y. Huh)

Jill Feldman, 54, poses for a photo at her home in Deerfield, Ill., Friday, Jan. 19, 2024. Lung cancer patient and advocate Jill Feldman takes pills at home that shrink tumors by blocking a signal that tells cancer cells to grow. (AP Photo/Nam Y. Huh)

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Photos and a sign are seen at Jill Feldman’s home in Deerfield, Ill., Friday, Jan. 19, 2024. Lung cancer patient and advocate Jill Feldman takes pills at home that shrink tumors by blocking a signal that tells cancer cells to grow. (AP Photo/Nam Y. Huh)

For cancer patients, the harsh side effects of powerful drugs have long been the trade-off for living longer. Now, patients and doctors are questioning whether all that suffering is necessary.

They’ve ignited a movement to radically change how new cancer drugs are tested, with the U.S. Food and Drug Administration urging drugmakers to do a better job at finding the lowest effective dose, even if it takes more time.

Advances in treatment mean millions of people are surviving for years with incurable cancers. Jill Feldman, 54, of Deerfield, Illinois, has lived 15 years with lung cancer, thanks to that progress. Her parents both died of lung cancer months after their diagnoses.

But her cancer drug causes joint pain, fatigue and mouth sores that make eating and drinking painful.

FILE - This Feb. 20, 2015 photo shows an arrangement of peanuts in New York. Xolair, the brand name for the drug omalizumab, used to treat asthma can now be used to help people with food allergies avoid severe reactions, the U.S. Food and Drug Administration said Friday, Feb. 16, 2024. (AP Photo/Patrick Sison, File)

“If you drink something that’s too hot, you really burn your mouth. That’s how my mouth feels 24/7,” Feldman said.

She has lowered the dose with her doctor’s blessing but she wants drugmakers to study lower doses early in the research process.

“No one should have to endure avoidable harmful effects of treatment,” she said.

Unlike in other diseases, cancer drug development has focused on finding what’s called the “maximum tolerated dose.”

To speed testing of chemotherapy drugs, researchers ramp up the dosage in a few people in early studies to determine the highest possible dose patients can tolerate. That “more is better” philosophy works for chemotherapy, but not necessarily for newer cancer drugs — like the one Feldman takes — which are more targeted and work differently.

Chemotherapy is like a battering ram where aggressive strikes are a good strategy. But newer cancer drugs are more like having a front door key. They target a mutation that drives cancer cell growth, for example, or rev up the body’s immune system to join the fight.

“You might only need a low dose to turn off that cancer driver,” said Dr. Lillian Siu, who leads cancer drug development at the Princess Margaret Cancer Center in Toronto. “If you can get the same bang for your buck, why go higher?”

Through a program called Project Optimus , the FDA is pushing drugmakers to include more patients in early dose-finding trials to get better data on when lower doses can work. A key motivation for the project was “the growing calls from patients and advocates that cancer drugs be more tolerable,” said FDA spokesperson Chanapa Tantibanchachai in an email.

Many of the new cancers drugs were developed using the old strategy. That leads to problems when patients skip doses or stop taking the drugs because of side effects. Some dose recommendations have been officially lowered after the drugs were approved. Other dose-lowering happens one patient at a time. Nearly half of patients in late-stage trials of 28 targeted therapy drugs needed to have their doses lowered, according to one study.

“We were pushing the dose as high as we could go,” said Dr. Patricia LoRusso, who leads drug discovery at Yale Cancer Center. “You get side effects and then you have to stop the drug to recover from the side effects and the tumor can grow.”

There’s also huge patient-to-patient variation. The amount of a pill that reaches the bloodstream can vary because of liver and kidney function and other differences. But that means lowering the dose for everyone risks underdosing some patients, LoRusso said.

“The challenge is: Where is the sweet spot?” LoRusso said.

Dr. Julie Gralow, chief medical officer of the American Society of Clinical Oncology, is planning a 500-patient study to test lower doses of two drugs for breast cancer that has spread.

The study will compare two strategies: Starting treatment at the full dose then lowering the dose for side effects versus starting with a lower dose and increasing dosage if the patient does well.

Much of the questioning of high doses has come from metastatic breast cancer patients, including the Patient Centered Dosing Initiative, which has done influential surveys of patients and cancer doctors.

“We will be on treatment for the rest of our lives,” said Lesley Kailani Glenn, 58, of Central Point, Oregon. “We want to try to live the best that we can, knowing that treatment is never-ever going to stop.”

During the 11 years she’s lived with the disease, she has summited Mount Whitney in California, hiked the Cinque Terra in Italy and started a nonprofit.

When Glenn learned how cancer drug research favors high doses, she started working with her doctor. She has taken drugs at lower doses and even lower when she can’t live with the side effects. Diarrhea is her deal-breaker: She wants to be able to walk her dog or shop for groceries without worrying about a bathroom emergency.

“The last thing we want to do is have our quality of life stolen from us,” Glenn said.

Through Project Optimus, the FDA is encouraging drug developers to conduct more head-to-head dosing comparisons. That could slow down the process, said Dr. Alice Shaw, who leads early cancer drug development at Novartis.

“That will require more patients and then, as you can imagine, also will require more time to identify, enroll and treat those patients,” said Shaw said. Adding six months to a year to the process, Shaw said, needs to be balanced against the urgent need for new cancer drugs.

But getting the dose right early will in the long run lead to more effective drugs, said Dr. Timothy Yap, a drug developer at MD Anderson Cancer Center in Houston. “If the patients are not taking the drug, then it’s not going to work.”

The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Science and Educational Media Group. The AP is solely responsible for all content.

research article on cancer cells

Cancer Cell Biology Research

A dividing breast cancer cell.

A dividing breast cancer cell.

Research in cancer cell biology seeks to define the biological basis underlying the differences between normal cells and cancerous cells. This includes studies of the fundamental mechanisms that drive pre-cancer states, oncogenic transformation, and that support tumor growth and behavior. Mechanistic understanding of this biology and the fundamental processes governing transformation, including the role of aging, gender, and ethnic disparities, are critical for identifying molecular targets for therapeutic or preventive interventions.

Research in this area is supported and directed by the Cancer Cell Biology Branch (CCBB) .

Cancer Cell Metabolism

Research in cancer cell metabolism focuses on altered cellular metabolic pathways that support the cancer phenotype, which is characterized by unchecked cell proliferation, resistance to metabolic and oxidative stress, evasion of programmed cell death, reduced dependence on growth factor signals, insensitivity to growth inhibitory signals, and resistance to therapeutic interventions.

Key research areas include:

  • Oncogenic reprogramming of cellular metabolism (e.g., the Warburg Effect, glutamine addiction, upregulated/deregulated fatty acid metabolism)
  • The links between protein translation, ribosome biogenesis, and metabolism
  • Tumor metabolite profiling and characterization
  • Regulation and mechanisms of nutrient, metabolic intermediate, and ion transport in cancer cells

Emerging areas in cancer metabolism include biological functions of metabolic intermediates, the molecular link between body homeostasis and cancer cell biology, mechanisms underlying the intersection between obesity and cancer, the metabolic plasticity of cancer cells, the mechanisms through which diet and fasting affect cancer initiation and maintenance, and the molecular mechanisms that lead to cancer cachexia.

Cancer Cell Stress Responses

Research in cancer cell stress responses focuses on the cell’s reaction to intrinsic and environmental stressors that determine whether a cell will die or adapt to survive. Examples of the types of stress included in this research area are oxidative stress, oncogenic stress, accumulation of unfolded or misfolded proteins, hypoxia, metal ions, chemotherapy, and inflammation.

  • Mechanisms of cell death (e.g., apoptosis, necrosis/necroptosis, autophagy, anoikis, ferroptosis, and other forms of programmed/non-programmed cell death)
  • Recycling of cellular components in response to stress (e.g., autophagy, mitophagy, lipophagy)
  • ER stress and the unfolded protein response
  • Exosome release as a mediator of cellular stress response and intercellular communications
  • Altered processing of growth factors and their associated receptors
  • Mechanisms of cellular control of toxic byproducts from biological processes (e.g., redox control)

Emerging areas relevant to this research include mechanisms of metal ions homeostasis, such as iron and copper, and their associated cellular targets and functions, and understanding the global effects of metal ions accumulation. 

Organelle Biology

Research in the area of organelle biology investigates the mechanisms and role of dysregulated organelle biology in driving or supporting the cancer phenotype.

  • Dysregulation of organelle biogenesis and function (e.g., mitochondria, endoplasmic reticulum, Golgi, lysosomes, lipid droplets, peroxisomes, endosomes, and cilia)
  • Processing and trafficking of intracellular membranes and proteins
  • Endocytosis and endosome sorting and recycling
  • Interactions between nuclear-encoded oncogenic proteins and mitochondrial function
  • Role of cell organelles in cancer-associated phenotypes

Emerging areas relevant to this research include regulation of mitochondrial growth and division, energy-independent functions of mitochondria, and the intersection between organelle structure/morphology and the phenotypic state or function of cancer cells. 

Cancer Cell Cycle Control

Photo of Dr. Sita Kugel

Dr. Sita Kugel Investigates the Biology of Pancreatic Cancer and Cholangiocarcinoma

Cell cycle dysregulation is a hallmark of cancer, and cell cycle components have been aggressively

targeted in chemotherapeutic strategies. Research in this area focuses on altered cell cycle regulation and its contribution to oncogenic transformation and tumor maintenance.

  • Characterization of factors that regulate cell cycle, mitosis, cytokinesis, centrosome duplication, and DNA replication in cancer cells 
  • Alternative, kinase-independent functions of cell cycle regulators
  • Mechanisms that alter protein stability and function of cell cycle components in cancer cells
  • Understanding the biological effects of cell cycle inhibitors in tumors, either alone or in combination with other therapies

Emerging areas relevant to this research include the elucidation of nutrient-sensing cell cycle checkpoints,  understanding mechanisms that allow for the bypass of cell cycle checkpoints, and exploration of combination therapies with CDK inhibitors for certain cancers.

Post-transcriptional Regulations Influencing Cancer

Research in this area investigates the wide-ranging mechanisms and functional effects of post-transcriptional regulations  that affect  the cancer phenotype.

  • Altered mechanisms and regulations of RNA stability, splicing, modifications, transport, and mRNA translation
  • Regulation and mechanisms of alternative splicing in cancer
  • The role of non-coding RNAs and RNA binding proteins in the regulation of splicing, modifications, transport, translation, and mRNA stability
  • Translation factors that act as oncogenes or tumor suppressors
  • Changes in protein maturation and stability, including diverse post-translation modifications (e.g., phosphorylation, acetylation, methylation, hydroxylation, ubiquitylation, sumoylation, neddylation, and glycosylation), as well as modifications of signaling effectors (e.g., promotors and drivers of tumorigenesis or cancer progression)

Emerging areas relevant to this research include the study of chemical modifications to RNAs and protein molecules, including writers, erasers, and readers of such modifications, that affect their stability, trafficking, RNA splicing and translation, and protein function, the development of novel technologies for efficient profiling of these modifications, and the interplay of different modifications and their alterations in cancer.

Basic Mechanisms of Cell Transformation

Research in this area includes mechanisms and effectors that govern the transition from normal cell to pre-cancer, early lesion, and cancer cell, as well as the identification of early biological events in transformation. Studies cover the role of tumor-initiating cells, field cancerization, and diverse signaling pathways governing cell fate determination and tumor formation. Research also examines the functions and regulations of oncogenes and tumor suppressor genes/proteins.  

  • Functional and molecular characterization of oncogenes and tumor suppressors and their affected pathways
  • Oncogenic signal transduction and their rewiring
  • The biology of tumor-initiating cells and cancer stem cells
  • Role of developmental and cell differentiation programs in preneoplasia and cancer
  • Senescence as an oncogenic or tumor suppressive mechanism, the relationship between quiescence and senescence states, and the relationship between senescence, aging, and cancer

Emerging areas relevant to this research include understanding lineage affiliation of stem and progenitor cells and its role in oncogenesis, characterizing the actual cell targets for oncogenic transformation, and deciphering the functional effects of multiple mutations in normal cells and their role in transformation. 

Biospecimen Resources to Support Cancer Biology Research

Research in this area includes the development of projects that encompass the collection, storage, processing, and dissemination of human biological specimens—including nucleic acids and tissue arrays—and associated data for studies of human cancer biology, particularly early events in cancer formation and pre-neoplasia. 

CWRU researchers find key to killing cancer may be in traps set by blood cells

  • Published: Feb. 13, 2024, 9:00 a.m.

cancer cell

Study finds that certain cancer drugs hijack white blood cells called neutrophils to kill cancers. Case Western Reserve University

  • Gretchen Cuda Kroen, cleveland.com

CLEVELAND, Ohio — Researchers at Case Western Reserve University have found that when two kinds of chemotherapy drugs are used together, white blood cells known as neutrophils explode and form a sticky web that traps and kills the cancer cells.

“We reported a novel discovery that some cancer medications trigger ‘cell blasters’ to kill cancer,” said Zhenghe “John” Wang , one of the study’s authors and chair of the Department of Genetics and Genome Sciences at the School of Medicine

The discovery explains why some combinations of chemotherapy work so well; because they induce these neutrophil traps and engage of the body’s natural defense mechanisms.

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This process of cell destruction is not specific to cancer cells. Neutrophils typically use this line of defense against bacteria.

White blood cells are the immune system’s first line of defense against bacterial infection. Neutrophils, the most abundant white blood cells, undergo a self-destructive process to release web-like structures — called “neutrophil extracellular traps,” referred to as NETs — to trap and kill bacteria, Wang explained.

But their study found that these NETs also seem to be crucial in stopping the growth of colon cancer in mice. The researchers discovered that combining two specific chemotherapy drugs (CB-839 and 5-FU) stopped the growth of a type of colon cancer in mouse models that involves PIK3CA — a gene that controls cell growth. They credited the success partly on NETs, because the drugs weren’t as effective when the traps were disturbed.

“We found that patients with tumors that have increased amounts of NETs after the drug treatment survived longer,” Wang said. “We found that certain cancer drugs hijack these neutrophils to kill cancers using extracellular traps. So, our study reveals a new way cancer drugs work, paving the way for the design of new cancer treatments.”

The results were recently published in January in The Journal of Clinical Investigation .

The study could have a broader impact beyond colorectal cancer, Wang said, because PIK3CA, is not unique to colorectal cancers. In fact, it is mutated in about 20% of all human cancers, and researchers believe that the same cell-blasting mechanisms may also apply to other NET-related diseases.

The group has recently been awarded a two-million-dollar federal grant to explore how chemotherapies modulate NET production and then use what they learn to design novel cancer treatments.

Gretchen Cuda Kroen

Stories by Gretchen Cuda Kroen

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Cancer stem cells articles from across Nature Portfolio

Cancer stem cells are rare immortal cells within a tumour that can both self-renew by dividing and give rise to many cell types that constitute the tumour, and can therefore form tumours. Such cells have been found in various types of human tumours and might be attractive targets for cancer treatment.

research article on cancer cells

Repurposing the dopamine transporter antagonist vanoxerine to treat colorectal cancer

Self-renewing cancer stem cells drive tumor initiation and progression and represent a major target for therapeutic development. A study now shows that vanoxerine, a dopamine transporter antagonist, precisely inhibits this cell population in colorectal cancer, which leads to attenuation of tumor initiation and increased infiltration by immune cells.

  • Winnie Chen

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Tissue-location-specific transcription programs drive tumor dependencies in colon cancer

Cancers of the same tissue type are characterized with different molecular features depending on anatomical location. Here, the authors show that proximal and distal colon stem cells have distinct transcriptional programs mediated by the transcription factor CDX2, with differential roles in colon cancers based on anatomical location.

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CD24 induced cellular quiescence-like state and chemoresistance in ovarian cancer cells via miR-130a/301a-dependent CDK19 downregulation

  • Yeonsue Jang
  • Nam Hoon Cho

research article on cancer cells

Leukemic stem cells activate lineage inappropriate signalling pathways to promote their growth

In Acute Myeloid Leukemia a population of quiescent leukemic stem cells (LSCs) evade chemotherapy and initiate relapse, but what makes them grow again is unknown. Here, the authors show (i) that LSCs hijack ectopic signaling pathways to kick-start their growth and (ii) that growth can be blocked with repurposed drugs in t(8;21) AML sub-type.

  • Sophie G. Kellaway
  • Sandeep Potluri
  • Constanze Bonifer

research article on cancer cells

SALL4 promotes cancer stem-like cell phenotype and radioresistance in oral squamous cell carcinomas via methyltransferase-like 3-mediated m6A modification

  • Junhong Huang
  • Jianhua Wei

research article on cancer cells

The dopamine transporter antagonist vanoxerine inhibits G9a and suppresses cancer stem cell functions in colon tumors

Benoit and colleagues identify the dopamine transporter antagonist vanoxerine as a suppressor of G9a methyltransferase and show that treatment leads to cancer stem cell suppression and restoration of an immunoresponsive tumor microenvironment in CRC.

  • Christopher J. Bergin
  • Aïcha Zouggar
  • Yannick D. Benoit

research article on cancer cells

Aggresome formation promotes ASK1/JNK signaling activation and stemness maintenance in ovarian cancer

The role of aggresomes in tumorigenesis and cancer progression remains to be explored. Here, the authors perform multi-omics and reveal that aggresome formation supports ovarian cancer stem cell properties via OTUD1 and ASK1/JNK signalling activation.

  • Yulong Qiang

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research article on cancer cells

Cholesterol-fuelled glioblastoma

Zhao et al. identified lymphatic endothelial-like cells in glioblastoma and demonstrated their role in promoting tumour growth through increased glioblastoma cholesterol metabolism.

  • Gabrielle Brewer

research article on cancer cells

Cell origin of BRCA2 -mutant breast cancer

The different compartments of the mammary stem cell hierarchy develop into distinct breast cancer subtypes as a result of specific genetic lesions. A recent study identifies aberrant ERBB3 low luminal progenitors with altered proteostasis and translation as the cell of origin of BRCA2 -mutant breast cancer.

research article on cancer cells

Pressing defence

In this study, Bansaccal et al. analyse why, at some skin locations, oncogene-expressing cells rarely progress to cancer and found that a dense dermal collagen network prevents skin cancer formation.

  • Daniela Senft

research article on cancer cells

Inflammation drives pressure on TP53 mutant clones in myeloproliferative neoplasms

Transformation of a myeloproliferative neoplasm to a secondary acute myeloid leukemia is rare but devastating. Single-cell, multi-omic characterization of hematopoietic stem and progenitor cells now shows the role of inflammation in transformation driven by mutations in TP53 , with effects on the mutant clone but also non-mutant counterparts.

  • Adam Benabid
  • Rebekka K. Schneider

research article on cancer cells

Deposition of complement components C5b-9 and MASP2 in tissues is not a feature of GVHD and may assist in discriminating GVHD from thrombotic microangiopathy following allogenic transplantation

  • Mohammad Alhomoud
  • Cynthia Magro
  • Jeffrey Laurence

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research article on cancer cells

IMAGES

  1. (PDF) Cancer stem cells: An insight

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  2. (PDF) Cancer Stem Cell Biology

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  3. Key Step Discovered to the Successful T-Cell Invasion of Tumors

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  4. EnGeneIC Announces Publication in Cancer Cell of a Scientific Paper

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  5. (PDF) The Implications of Cancer Stem Cells for Cancer Therapy

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  6. (PDF) Eradicating Cancer Stem Cells: Concepts, Issues, and Challenges

    research article on cancer cells

COMMENTS

  1. Cancer Biology, Epidemiology, and Treatment in the 21st Century: Current Status and Future Challenges From a Biomedical Perspective

    The Biology of Cancer. Cancer is a disease that begins with genetic and epigenetic alterations occurring in specific cells, some of which can spread and migrate to other tissues. 4 Although the biological processes affected in carcinogenesis and the evolution of neoplasms are many and widely different, we will focus on 4 aspects that are particularly relevant in tumor biology: genomic and ...

  2. Focusing on the cell biology of cancer

    This month, we launch a series of specially commissioned review and perspective articles on cancer cell biology, covering key topics and recent advances in understanding the cellular mechanisms ...

  3. Using cancer's strength to fight against it

    "Mutations underlying the resilience and adaptability of cancer cells can super-charge T cells to survive and thrive in the harsh conditions that tumors create," said Kole Roybal, associate professor of microbiology and immunology at UCSF, center director for the Parker Institute for Cancer Immunotherapy Center at UCSF, and a member of the ...

  4. How cancer hijacks the nervous system to grow and spread

    Related Articles. Cancer cells have 'unsettling' ability to hijack the brain's nerves ... Consider joining the Center for Cancer Research (CCR) at the National Cancer Institute. Bethesda ...

  5. Cancer articles: The New England Journal of Medicine

    N Engl J Med 2023; 389:1851-1861. Selpercatinib, an oral, selective, brain-penetrant RET kinase inhibitor, was compared with multikinase inhibitors in advanced medullary thyroid cancer. At 12 ...

  6. Research articles

    Research articles. Filter By: Article Type. All. All; Analysis (8) ... Schmid and colleagues show that pancreatic cancer cell colonization of the liver is accompanied by low-grade tissue injury ...

  7. Research Areas: Cancer Biology

    NCI supports and directs cancer biology research through a variety of programs and approaches. For example: The Metastasis Research Network (MetNet) supports research to improve our understanding of how cancer spreads. Cancer metastasis is a complex, dynamic, nonlinear process. The network supports several specialized centers working ...

  8. Cancer cells use self-inflicted DNA breaks to evade growth limits

    Irradiated normal cells halt progression in the G 1 phase of the cell cycle by activation of p53 and pRB, which are key factors regulating cell cycle checkpoints. However, these factors are commonly inactivated in solid cancers, leading to G 1 checkpoint deficiency. Combined with oncogene-driven premature S-phase entry, this scenario evokes replication stress and enhanced chromosomal damage ...

  9. Cancer Treatment Research

    Two research teams have developed a treatment approach that could potentially enable KRAS-targeted drugs—and perhaps other targeted cancer drugs—flag cancer cells for the immune system. In lab studies, the teams paired these targeted drugs with experimental antibody drugs that helped the immune system mount an attack.

  10. Stopping the cancer cells that thrive on chemotherapy

    Exposing pancreatic cancer cells to chemotherapy drugs, which are designed to impose stress upon cancer cells, also triggers an increase of LPAR4 on cancer cells. This finding might explain how ...

  11. CRISPR in cancer biology and therapy

    In one example, a genome-wide screen using cancer cells co-cultured with cytotoxic T cells revealed cancer cell-intrinsic regulators of T cell killing 242. The study identified receptor ...

  12. Stanford Medicine scientists transform cancer cells into weapons

    The work was supported by funding from the Ludwig Foundation for Cancer Research, the Emerson Collective Cancer Research Fund, the New York Stem Cell Foundation, the Stinehart-Reed Foundation, the Leukemia and Lymphoma Society, the J. Benjamin Eckenhoff Fund, the Blavatnik Family Fellowship, the Deutsche Forschungsgemainshaft, the Knut and ...

  13. FDA approves groundbreaking treatment for advanced melanoma

    Putting billions of cells back into the body is not entirely risk-free, however, said Dr. William Dahut, chief scientific officer of the American Cancer Society.

  14. As cancer treatment advances, patients and doctors push back against

    They target a mutation that drives cancer cell growth, for example, or rev up the body's immune system to join the fight. "You might only need a low dose to turn off that cancer driver," said Dr. Lillian Siu, who leads cancer drug development at the Princess Margaret Cancer Center in Toronto.

  15. DCB

    Credit: National Cancer Institute. Research in cancer cell biology seeks to define the biological basis underlying the differences between normal cells and cancerous cells. This includes studies of the fundamental mechanisms that drive pre-cancer states, oncogenic transformation, and that support tumor growth and behavior.

  16. Cancer at Nature Portfolio

    The Nature Portfolio editors who handle cancer primary research, methods, protocols and reviews bring you the latest articles, covering all aspects from disease mechanisms to therapeutic ...

  17. New articles: Cancer Cell

    The brain tumor-associated vasculature is a key component of the tumor microenvironment in brain metastasis, protecting cancer cells from immune attack and interfering with the delivery of therapeutic agents into the brain. In this study, Bejarano et al. unravel the vascular heterogeneity in human BrM and further construct a preclinical ...

  18. Why age matters when it comes to cancer

    Studies have also found that these accumulating mutations impair the ability of immune cells to suppress and destroy cancer cells. In particular, Masashi Narita, who researches cancer and ageing ...

  19. In 'major milestone,' FDA approves first cell therapy for ...

    Metastatic melanoma cells Julio C. Valencia,/NCI Center for Cancer Research. ... a cell therapy researcher and physician at Stanford University who has worked on Amtagvi. "This is a game ...

  20. Turbocharged CAR-T cells melt tumours in mice

    A cancer cell (blue; artificially coloured) is targeted by an engineered immune cell (purple), which can be enhanced by mutations originally discovered in cancer cells. Credit: Steve Gschmeissner ...

  21. CWRU researchers find key to killing cancer may be in traps set by

    This process of cell destruction is not specific to cancer cells. Neutrophils typically use this line of defense against bacteria. White blood cells are the immune system's first line of defense ...

  22. Cancer Cell Research

    Conclusion: The expression of COL21A1 was significantly down-regulated in colon cancer tissues. Its down-regulation was correlated with immune cell infiltration and immunomodulatory molecule contents in colon cancer tissues. An in-depth investigation on COL21A1 may be beneficial for the immunotherapy of colon cancer. Full article

  23. Cancer stem cells

    Cancer stem cells articles from across Nature Portfolio. Cancer stem cells are rare immortal cells within a tumour that can both self-renew by dividing and give rise to many cell types that ...