It has long been recognized that cancer onset and progression represent a type of reversion to an ancestral quasi‐unicellular phenotype. This general concept has been refined into the atavistic model of cancer that attempts to provide a quantitative analysis and testable predictions based on genomic data. Over the past decade, support for the multicellular‐to‐unicellular reversion predicted by the atavism model has come from phylostratigraphy. Here, we propose that cancer onset and progression involve more than a (...) one‐off multicellular‐to‐unicellular reversion, and are better described as a series of reversionary transitions. We make new predictions based on the chronology of the unicellular‐eukaryote‐to‐multicellular‐eukaryote transition. We also make new predictions based on three other evolutionary transitions that occurred in our lineage: eukaryogenesis, oxidative phosphorylation and the transition to adaptive immunity. We propose several modifications to current phylostratigraphy to improve age resolution to test these predictions. Also see the video abstract here: https://youtu.be/3unEu5JYJrQ. (shrink)

Adherens (AJ) and tight junctions (TJ) maintain cell‐cell adhesions and cellular polarity in normal tissues. Afadin, a multi‐domain scaffold protein, is commonly found in both adherens and tight junctions, where it plays both structural and signal‐modulating roles. Afadin is a complex modulator of cellular processes implicated in cancer progression, including signal transduction, migration, invasion, and apoptosis. In keeping with the complexities associated with the roles of adherens and tight junctions in cancer, afadin exhibits both tumor suppressive and (...) pro‐metastatic functions. In this review, we will explore the dichotomous roles that afadin plays during cancer progression. (shrink)

The current mainstream in cancer research favours the idea that malignant tumour initiation is the result of a genetic mutation. Tumour development and progression is then explained as a sort of micro-evolutionary process, whereby an initial genetic alteration leads to abnormal proliferation of a single cell that leads to a population of clonally derived cells. It is widely claimed that tumour progression is driven by natural selection, based on the assumption that the initial tumour cells acquire some (...) properties that endow such cells with a selective advantage over the normal cells from which the tumour cells are derived. The standard view assumes that the transformed bodily cell somehow acquires "responsiveness" to natural selection independently of the whole organism to which the cell belongs. Yet, it is never explained where such an acquired capacity to respond to natural selection by the individual bodily cell comes from. This situation poses many difficult questions that so far have been left unanswered. For example, there is no explanation why some cells belonging to an organised whole and as such having no independent capacity for survival, apparently become 'independent' entities, able to respond to selective pressures in an autonomous fashion and then to be evaluated by natural selection. Hereunder it is argued that such a qualitative change cannot be the consequence of specific genetic mutations. Moreover, it is shown that natural selection is unlikely to be acting within the organism during tumour development and progression and that tumour evolution is a random, non-adaptive process, driven by no fundamental biological principle. Thus, mutations in the so-called oncogenes and tumour suppressor genes observed in epithelial cancers (that constitute more than 90% of all cancers) are not the result of selection for better cellular growth or survival under restrictive conditions. Instead, here it is suggested that they are the consequence of genetic drift acting upon gene functions that become non-relevant, either for the individual or the species fitness, once the organism is past its reproductive prime and as such, they also become superfluous for cell survival in the short term. It is proposed that the origin of cancer is epigenetic and it is a consequence of the need for a continued turnover of the individuals that constitute a species. (shrink)

In the atavistic model of cancer progression, tumor cell dedifferentiation is interpreted as a reversion to phylogenetically earlier capabilities. The more recently evolved capabilities are compromised first during cancer progression. This suggests a therapeutic strategy for targeting cancer: design challenges to cancer that can only be met by the recently evolved capabilities no longer functional in cancer cells. We describe several examples of this target‐the‐weakness strategy. Our most detailed example involves the immune system. (...) The absence of adaptive immunity in immunosuppressed tumor environments is an irreversible weakness of cancer that can be exploited by creating a challenge that only the presence of adaptive immunity can meet. This leaves tumor cells more vulnerable than healthy tissue to pathogenic attack. Such a target‐the‐weakness therapeutic strategy has broad applications, and contrasts with current therapies that target the main strength of cancer: cell proliferation. (shrink)

From an evolutionary perspective, both atavism and somatic evolution/convergent evolution theories can account for the consistent occurrence, and astounding attributes of cancers: being able to evolve from a single cell to a complex organized system, and malignant transformations showing significant similarities across organs, individuals, and species. Here, we first provide an overview of these two hypotheses, including the possibility of them not being mutually exclusive, but rather potentially representing the two extremes of a continuum in which the diversity of cancers (...) can emerge. In reviewing the current literature, we also discuss the criteria that should be applied to discriminate between the two competing theories and to determine their relevant contributions to oncogenesis and cancer progression. Finally, we deliberate on the potential applications of this conceptual framework in developing novel treatment strategies. (shrink)

Background: Fear of cancer recurrence or progression is a common challenge experienced by people living with and beyond cancer and is frequently endorsed as the highest unmet psychosocial need amongst survivors. This has prompted many cancer organizations to develop self-help resources for survivors to better manage these fears through psychoeducation, but little is known about whether they help reduce FCR/P.Method: We recruited 62 women with ovarian cancer. Women reported on their medical history and demographic characteristics (...) and completed the Fear of Progression Questionnaire-Short Form. They then read a booklet on FCR specifically created for Ovarian Cancer Australia by two of the authors. One week after reading the booklet, 50/62 women completed the FoP-Q-SF and answered questions about their satisfaction with the booklet.Results: More than half of the women scored in the clinical range for FCR/P at baseline. Of the completers, 93% said that they would recommend the booklet to other women. Satisfaction with the booklet was relatively high and more than two-thirds of women rated it as moderately helpful or better. However, FCR/P did not change significantly over the week following reading the booklet [t = 1.71, p = 0.09]. There was also no difference in change in FCR/P between women in the clinical vs. non-clinical range on the FoP-Q. Women high in FCR/P rated the booklet as less helpful in managing FCR/P, but overall satisfaction with the booklet was not associated with degree of FCR/P.Conclusions: These results suggest that a simple online FCR booklet is acceptable to women with ovarian cancer and they are satisfied with the booklet, but, it was insufficient to change in FCR/P levels. These results suggest that such resources are valued by women with ovarian cancer, but more potent interventions are necessary to reduce FCR in this population. (shrink)

As the spread of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) continues to surge worldwide, our knowledge of coronavirus disease 2019 (COVID‐19) is rapidly expanding. Although most COVID‐19 patients recover within weeks of symptom onset, some experience lingering symptoms that last for months (“long COVID‐19”). Early reports of COVID‐19 sequelae, including cardiovascular, pulmonary, and neurological conditions, have raised concerns about the long‐term effects of COVID‐19, especially in hard‐hit communities. It is becoming increasingly evident that cancer patients are more susceptible (...) to SARS‐CoV‐2 infection and are at a higher risk of severe COVID‐19 than the general population. Nevertheless, whether long COVID‐19 increases the risk of cancer in those with no prior malignancies, remains unclear. Given, the disproportionate impact of the disease on the African American community, yet another unanswered question is whether racial disparities are to be expected in COVID‐19 sequelae. Herein, we propose that long COVID‐19 may predispose recovered patients to cancer development and accelerate cancer progression. This hypothesis is based on growing evidence of the ability of SARS‐CoV‐2 to modulate oncogenic pathways, promote chronic low‐grade inflammation, and cause tissue damage. Comprehensive studies are urgently required to elucidate the effects of long COVID‐19 on cancer susceptibility. (shrink)

Cancer—and scientific research on cancer—raises a variety of compelling philosophical questions. This entry will focus on four topics, which philosophers of science have begun to explore and debate. First, scientific classifications of cancer have as yet failed to yield a unified taxonomy. There is a diversity of classificatory schemes for cancer, and while some are hierarchical, others appear to be “cross-cutting,” or non-nested. This literature thus raises a variety of questions about the nature of the disease (...) and disease classification. Second, philosophers of science have historically taken the aim of science to be arriving at true theories. However, scientists studying cancer come from a variety of disciplines, with different scientific as well as practical aims. Perhaps it is not surprising, then, that historians and philosophers of science do not seem to agree on how best to characterize the aim and structure of cancer research; it is far from clear whether the appropriate characterization of the aim is arriving at true theories, or even whether the proper units of analysis are “theories”, or instead, “models”, “explanatory frameworks”, “research programs”, “paradigms”, or perhaps, “experimental traditions”. With the rise of “big data” science—such as the Cancer Genome Atlas Project (or TCGA)—and “systems” approaches to the study of disease, both philosophers and historians of science are rethinking how best to describe and explain these distinctive kinds of scientific inquiry. -/- Third, cancer is in part a byproduct of our developmental and life history, as well as our evolutionary history. Cancer progression can be compared to a reversion of development, or, to the evolution of multicellularity. Thus, cancer raises intriguing questions about how we conceive of “functions”, “development”, and the role of our evolutionary history and particularly, selective trade-offs, in vulnerability to disease. -/- Last but not least, cancer research provides a case study for consideration of the roles of values at the science-policy interface. Epidemiological and toxicological research on cancer’s causes informs toxics law and regulatory policy, which raises a variety of questions about the nature of evidence and inductive risk in such contexts. (shrink)

We present here the hypothesis that the unique microenvironmental pH landscape of acid‐base transporting epithelia is an important factor in development of epithelial cancers, by rendering the epithelial and stromal cells pre‐adapted to the heterogeneous extracellular pH (pHe) in the tumor microenvironment. Cells residing in organs with net acid‐base transporting epithelia such as the pancreatic ductal and gastric epithelia are exposed to very different, temporally highly variable pHe values apically and basolaterally. This translates into spatially and temporally non‐uniform intracellular pH (...) (pHi) patterns. Disturbed pHe‐ and pHi‐homeostasis contributes to essentially all hallmarks of cancer. Our hypothesis, that the physiological pHe microenvironment in acid‐base secreting epithelia shapes cancers arising in these tissues, can be tested using novel imaging tools. The acidic tumor pHe in turn might be exploited therapeutically. Pancreatic cancers are used as our prime example, but we propose that this concept is also relevant for other cancers of acid‐base transporting epithelia. (shrink)

Similar to parasites, cancer cells depend on their hosts for sustenance, proliferation and reproduction, exploiting the hosts for energy and resources, and thereby impairing their health and fitness. Because of this lifestyle similarity, it is predicted that cancer cells could, like numerous parasitic organisms, evolve the capacity to manipulate the phenotype of their hosts to increase their own fitness. We claim that the extent of this phenomenon and its therapeutic implications are, however, underappreciated. Here, we review and discuss (...) what can be regarded as cases of host manipulation in the context of cancer development and progression. We elaborate on how acknowledging the applicability of these principles can offer novel therapeutic and preventive strategies. The manipulation of host phenotype by cancer cells is one more reason to adopt a Darwinian approach in cancer research. -/- . (shrink)

Cancer is a paradigmatic case of a complex causal process; causes of cancer operate at a variety of temporal and spatial scales, and the respects in which these causes act and interact are diverse. There are, for instance, temporal order effects, organizational effects, structural effects, and dynamic relationships between causes operating at different temporal and spatial scales. Because of this complexity, models of cancer initiation and progression often involve deliberate choices to focus on one time scale, (...) one causal pathway, or one aspect of cancer’s dynamics. As in most of biology, modeling cancer involves simplification and idealization. At the same time, theoretical perspectives inform the construction of these models. Such perspectives might involve viewing cancer ‘as’ a genetic disease, metabolic disease, stem cell disease, an infectious disease, or a disease of tissue disorganization. This paper will argue that purportedly competing theoretical views of cancer are not at odds, but can be viewed as mutually informative. Models are most often developed in the service of asking very specific questions, and this requires limiting our view of the phenomena to a specific temporal or spatial scale, a particular cause, or a particular outcome, dynamic, or pattern. Thus, while some models may seem at odds, often they are simply concerned with different questions, or, they are complementary and mutually informative. I hope to bring this case to bear on debates among philosophers of science over perspectivism and realism, as well pluralism about the aims and scope of scientific theory. (shrink)

Cancer is an evolutionary and ecological process in which complex interactions between tumour cells and their environment share many similarities with organismal evolution. Tumour cells with highest adaptive potential have a selective advantage over less fit cells. Naturally occurring transmissible cancers provide an ideal model system for investigating the evolutionary arms race between cancer cells and their surrounding micro‐environment and macro‐environment. However, the evolutionary landscapes in which contagious cancers reside have not been subjected to comprehensive investigation. Here, we (...) provide a multifocal analysis of transmissible tumour progression and discuss the selection forces that shape it. We demonstrate that transmissible cancers adapt to both their micro‐environment and macro‐environment, and evolutionary theories applied to organisms are also relevant to these unique diseases. The three naturally occurring transmissible cancers, canine transmissible venereal tumour (CTVT) and Tasmanian devil facial tumour disease (DFTD) and the recently discovered clam leukaemia, exhibit different evolutionary phases: (i) CTVT, the oldest naturally occurring cell line is remarkably stable; (ii) DFTD exhibits the signs of stepwise cancer evolution; and (iii) clam leukaemia shows genetic instability. While all three contagious cancers carry the signature of ongoing and fairly recent adaptations to selective forces, CTVT appears to have reached an evolutionary stalemate with its host, while DFTD and the clam leukaemia appear to be still at a more dynamic phase of their evolution. Parallel investigation of contagious cancer genomes and transcriptomes and of their micro‐environment and macro‐environment could shed light on the selective forces shaping tumour development at different time points: during the progressive phase and at the endpoint. A greater understanding of transmissible cancers from an evolutionary ecology perspective will provide novel avenues for the prevention and treatment of both contagious and non‐communicable cancers. (shrink)

Phenotypic plasticity is a crucial feature of aggressive cancer, providing the means for cancer progression. Stochastic changes in tumor cell transcriptional programs increase the chances of survival under any condition. I hypothesize that unstable chromatin permits stochastic transitions between transcriptional programs in aggressive cancers and supports non‐genetic heterogeneity of tumor cells as a basis for their adaptability. I present a mechanistic model for unstable chromatin which includes destabilized nucleosomes, mobile chromatin fibers and random enhancer‐promoter contacts, resulting in (...) stochastic transcription. I suggest potential markers for “unsettled” chromatin in tumors associated with poor prognosis. Although many of the characteristics of unstable chromatin have been described, they were mostly used to explain changes in the transcription of individual genes. I discuss approaches to evaluate the role of unstable chromatin in non‐genetic tumor cell heterogeneity and suggest using the degree of chromatin instability and transcriptional noise in tumor cells to predict cancer aggressiveness. (shrink)

Parallels between cancer and ecological systems have been increasingly recognized and extensively reviewed. However, a more unified framework of understanding cancer as an evolving dynamical system that undergoes a sequence of interconnected changes over time, from a dormant microtumor to disseminated metastatic disease, still needs to be developed. Here, we focus on several examples of such mechanisms, namely, how in cancer niche construction a metabolic adaptation and consequent change to the tumor microenvironment becomes an important factor in (...) evasion of the predator, facilitating disease progression; how tumor establishment and propagation is driven by the tumor’s own keystone species, the cancer stem cells; and how the succession of stages of metastatic dissemination can be informed by ergodic theory and forest ecology. (shrink)

The genome is a stable repository of vastly intricate genetic information developed over eons of evolution; this information is replicated at the highest fidelity and expressed within each cell at the highest selectivity. Non‐leukemia cancers break this standard; the intricate genetic information qualitatively and progressively deteriorates, resulting in a somatic Darwinian free‐for‐all. In a process lasting several years, a genomically heterogeneous population replicates from a single cell that originally lost the ability to preserve its genomic integrity. Cells selected for their (...) abilities to proliferate and spread, while evading host defenses, inexorably expand their numbers. The clinical consequences of this become severe, as the genomically diverse cell population that evolves contains members that can evade most therapeutic approaches aimed at “the tumor cell”. BioEssays 23:1037–1046, 2001. © 2001 John Wiley & Sons, Inc. (shrink)

Human cancers comprise an heterogeneous array of diseases with different progression patterns and responses to therapy. However, they all develop within a host context that constrains their natural history. Since it occurs across the diversity of organisms, one can conjecture that there is order in the cancer multiverse. Is there a way to capture the broad range of tumor types within a space of the possible? Here we define the oncospace, a coordinate system that integrates the ecological, evolutionary (...) and developmental components of cancer complexity. The spatial position of a tumor results from its departure from the healthy tissue along these three axes, and progression trajectories inform about the components driving malignancy across cancer subtypes. We postulate that the oncospace topology encodes new information regarding tumorigenic pathways, subtype prognosis, and therapeutic opportunities: treatment design could benefit from considering how to nudge tumors toward empty evolutionary dead ends in the oncospace. (shrink)

Cancer cells seem to exploit mechanisms that evolve as part of physiological tolerance, which is a complementary and often beneficial form of defense. The study of physiological systems of tolerance can therefore provide insights into the development of a state of host tolerance of cancer, and how to break it. Analysis of these models has the potential to improve our understanding of existing immunological therapeutic targets, and help to identify future targets and rational therapeutic combinations. The treatment of (...) cancer with immune checkpoint inhibitors aims to reverse the progression to tolerance of cancer, and achieve an immunogenic, rather than tolerogenic, homeostasis. Broadening the efficacy and durability of checkpoint inhibitors focuses on reversing tolerance and stimulating immunogenicity in the cancer, host, and environment. Two examples of important physiological states of tolerance that may inform tolerance of cancer are microbial infection and placental reproduction. These states of tolerance result from bilateral shaping of host and non‐self, akin to immunoediting in cancer, and offer reliable models to study the immune tolerance paradigm. (shrink)

One of the major developments in cancer research in recent years has been the construction of models that treat cancer as a cellular population subject to natural selection. We expand on this idea, drawing upon multilevel selection theory. Cancer is best understood in our view from a multilevel perspective, as both a by-product of selection at other levels of organization, and as subject to selection at several levels of organization. Cancer is a by-product in two senses. (...) First, cancer cells co-opt signaling pathways that are otherwise adaptive at the organismic level. Second, cancer is also a by-product of features distinctive to the metazoan lineage: cellular plasticity and modularity. Applying the multilevel perspective in this way permits one to explain transitions in complexity and individuality in cancer progression. Our argument is a reply to Germain’s scepticism towards the explanatory relevance of natural selection for cancer. The extent to which cancer fulfills the conditions for being a paradigmatic Darwinian population depends on the scale of analysis, and the details of the purported selective scenario. Taking a multilevel perspective clarifies some of the complexities surrounding how to best understand the relevance of evolutionary thinking in cancer progression. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Bringing Cancer Care to Those who Don't Have ItLawrence N. ShulmanI have been treating cancer patients in the Harvard Medical School hospitals since 1977, and in those 35 years we have made tremendous progress. Though work still needs to be done, and far too many patients still die of cancer, many are cured. In particular, children and young adults have a high rate of cure from (...) such diseases as Hodgkin's lymphoma, non-Hodgkin's lymphoma, acute lymphoblastic leukemia, and childhood sarcoma. Patients with breast cancer in the US have a greater than 80% chance for long-term survival. The death rate from cervical cancer in the US is very low. These results have been achieved by making diagnoses earlier, in many cases surgical excision, and often systemic therapies such as chemotherapy, hormonal therapy, radiation therapy, and more recently by using so-called "targeted" therapies—those directed at particular molecular characteristics of the cancer cells.Princess Dina Mired has said that the opportunity to survive cancer should not be an accident of geography. In cases where we already have effective and inexpensive tools to cure cancer, these treatments should be considered a basic human right, a life-saving medical service.I met Patty, a young woman living in the U.S. during November of her senior year in high school, after she discovered a small lump above her left collar bone. Though she felt entirely well, she called her primary care doctor who saw her the next day, felt the enlarged lymph node, and referred her to a surgeon, who did a biopsy later that week. Her primary care doctor also called me, and we scheduled a visit when the pathology results were available. The following week the pathologist notified Patty's pediatrician that the biopsy showed Hodgkin's lymphoma. When I met Patty, she was a bright and focused young woman, waiting to hear about her college applications and enjoying her senior year. Her cancer diagnosis was completely out of context with her life as she planned it, but with the support of her family and boyfriend, she seemed prepared to take things one step at a time. A PET CT scan demonstrated a modest mass in the mediastinum (chest), but no other disease. She was in an early stage of the disease with an excellent prognosis. We recommended and administered six months of chemotherapy with doxorubicin, bleomycin, vinblastine, and dacarbazine—four chemotherapy agents that are off-patent, and relatively inexpensive. She lost her hair, not a trivial issue for her, but otherwise felt reasonably well during the treatment. She was determined to graduate with her classmates, and was able continue to attend school and keep up with her work. In June, seven months into her cancer diagnosis and treatment, she graduated with honors, and was on track to enroll in college in September.Like other 18-year-old women with Hodgkin's lymphoma, Patty had an over 80% chance for cure with the potential for a long and productive life ahead of her because we could perform a biopsy, make a diagnosis, and safely and effectively treat her with four inexpensive, off-patent, chemotherapy drugs. She had nearly the same likelihood of living a long and fruitful life as her classmates, and had the same chances for childbearing. In my line of work, with the knowledge we now possess, to allow someone like Patty to die without a chance of curative care is simply unacceptable. Treatment of curable cancers should be considered on par with the right to clean water, adequate nutrition, treatment for infectious disease, and access to maternal and child healthcare services.But in many places in the world, people with cancers we could easily eradicate in Boston have no access to cancer services, and do die unnecessarily. The local healthcare infrastructure has no [End Page E10] capacity to evaluate a patient, perform or process a biopsy, make a diagnosis, or treat the patient with potentially curative surgery, chemotherapy and radiation. I have rounded on the wards of hospitals in developing countries, stopping to talk with numerous patients like Patty: young women, some of whom might have had Hodgkin's lymphoma, but no... (shrink)

Graphical AbstractCancer is a complex disease, with sophisticated cellular mechanisms as the targets of evolutionary processes driven by random genetic and epigenetic mutations. Oncogenesis is evolutionarily linked to stem cell numbers/mutations and organ/body size; therefore, inter-disciplinary frameworks across different scales (cellular, tissue, organs and species) are necessary to decipher cancer progression.

Cancer stem cells (CSC) represent malignant cell subsets in hierarchically organized tumors, which are selectively capable of tumor initiation and self‐renewal and give rise to bulk populations of non‐tumorigenic cancer cell progeny through differentiation. Robust evidence for the existence of prospectively identifiable CSC among cancer bulk populations has been generated using marker‐specific genetic lineage tracking of molecularly defined cancer subpopulations in competitive tumor development models. Moreover, novel mechanisms and relationships have been discovered that link CSC to (...) cancer therapeutic resistance and clinical tumor progression. Importantly, proof‐of‐principle for the potential therapeutic utility of the CSC concept has recently been provided by demonstrating that selective killing of CSC through a prospective molecular marker can inhibit tumor growth. Herein, we review these novel and translationally relevant research developments and discuss potential strategies for CSC‐targeted therapy in the context of resistance mechanisms and molecular pathways preferentially operative in CSC. (shrink)

DNA methylation is a repressive epigenetic mark vital for normal development. Recent studies have uncovered an unexpected role for the DNA methylome in ensuring the correct targeting of the Polycomb repressive complexes throughout the genome. Here, we discuss the implications of these findings for cancer, where DNA methylation patterns are widely reprogrammed. We speculate that cancer‐associated reprogramming of the DNA methylome leads to an altered Polycomb binding landscape, influencing gene expression by multiple modes. As the Polycomb system is (...) responsible for the regulation of genes with key roles in cell fate decisions and cell cycle regulation, DNA methylation induced Polycomb mis‐targeting could directly drive carcinogenesis and disease progression.Editor's suggested further reading in BioEssays Unmasking risk loci: DNA methylation illuminates the biology of cancer predisposition Abstract. (shrink)

Once regarded as cellular ‘debris’ extracellular vesicles (EVs) emerge as one of the most intriguing entities in cancer pathogenesis. Intercellular trafficking of EVs challenges the notion of cancer cell autonomy, and highlights the multicellular nature of such fundamental processes as stem cell niche formation, tumour stroma generation, angiogenesis, inflammation or immunity. Recent studies reveal that intercellular exchange mediated by EVs runs deeper than expected, and includes molecules causative for cancer progression, such as oncogenes (epidermal growth factor (...) receptor, Ras), and tumour suppressors (PTEN). The uptake of oncogenic EVs (oncosomes) by various cells may profoundly change their biology, signalling patterns and gene expression, and in some cases cause their overt tumorigenic conversion. Moreover, EVs circulating in blood and present in body fluids provide an unprecedented access to the molecular circuitry driving cancer cells, and new technologies are being developed to exploit this property as a source of unique cancer biomarkers. (shrink)

In this review, we discuss the application of mouse models to the identification and pre‐clinical validation of novel therapeutic targets in colorectal cancer, and to the search for early disease biomarkers. Large‐scale genomic, transcriptomic and epigenomic profiling of colorectal carcinomas has led to the identification of many candidate genes whose direct contribution to tumourigenesis is yet to be defined; we discuss the utility of cross‐species comparative ‘omics‐based approaches to this problem. We highlight recent progress in modelling late‐stage disease using (...) mice, and discuss ways in which mouse models could better recapitulate the complexity of human cancers to tackle the problem of therapeutic resistance and recurrence after surgical resection. (shrink)

Here we review and discuss the link between regeneration capacity and tumor suppression comparing mammals (embryos versus adults) with highly regenerative vertebrates. Similar to mammal embryo morphogenesis, in amphibians (essentially newts and salamanders) the reparative process relies on a precise molecular and cellular machinery capable of sensing abnormal signals and actively reprograming or eliminating them. As the embryo's evil twin, tumor also retains common functional attributes. The immune system plays a pivotal role in maintaining a physiological balance to provide surveillance (...) against tumor initiation or to support its initiation and progression. We speculate that susceptibility to cancer development in adult mammals may be determined by the loss of an advanced regenerative capability during evolution and believe that gaining mechanistic insights into how regenerative capacity linked to tumor suppression is postnatally lost in mammals might illuminate an as yet unrecognized route to cancer treatment. (shrink)

NCG 4.0 is the latest update of the Network of Cancer Genes, a web-based repository of systems-level properties of cancer genes. In its current version, the database collects information on 537 known (i.e. experimentally supported) and 1463 candidate (i.e. inferred using statistical methods) cancer genes. Candidate cancer genes derive from the manual revision of 67 original publications describing the mutational screening of 3460 human exomes and genomes in 23 different cancer types. For all 2000 (...) class='Hi'>cancer genes, duplicability, evolutionary origin, expression, functional annotation, interaction network with other human proteins and with microRNAs are reported. In addition to providing a substantial update of cancer-related information, NCG 4.0 also introduces two new features. The first is the annotation of possible false-positive cancer drivers, defined as candidate cancer genes inferred from large-scale screenings whose association with cancer is likely to be spurious. The second is the description of the systems-level properties of 64 human microRNAs that are causally involved in cancer progression (oncomiRs). Owing to the manual revision of all information, NCG 4.0 constitutes a complete and reliable resource on human coding and non-coding genes whose deregulation drives cancer onset and/or progression. NCG 4.0 can also be downloaded as a free application for Android smart phones. (shrink)

The somatic mutation theory (SMT) of cancer has been and remains the prevalent theory attempting to explain how neoplasms arise and progress. This theory proposes that cancer is a clonal, cell‐based disease, and implicitly assumes that quiescence is the default state of cells in multicellular organisms. The SMT has not been rigorously tested, and several lines of evidence raise questions that are not addressed by this theory. Herein, we propose experimental strategies that may validate the SMT. We also (...) call attention to an alternative theory of carcinogenesis, the tissue organization field theory (TOFT), which posits that cancer is a tissue‐based disease and that proliferation is the default state of all cells. Based on epistemological and experimental evidence, we argue that the TOFT compellingly explains carcinogenesis, while placing it within an evolutionarily relevant context.magnified imagemagnified imageAna Soto and Carlos Sonnenschein are at Tufts University School of Medicine, Boston, MA, USA. (shrink)

Most basic research on cancer concerns genetic changes in benign and malignant tumors. Yet evidence indicates that the majority of the mutations in tumors occur in the preneoplastic field stage of their development. That early stage is represented by grossly invisible, broad regions of “field cancerization” which have not, heretofore, been operationally analyzed in cell culture. Conditions are described for quantitating preneoplasia by increased saturation density followed by progression to transformation. These parameters are driven by Darwinian selection of (...) spontaneously occurring, cumulative mutations, in accordance with recent genomic analyses of human cancer, just as it is in the evolution of species. The cell culture model will allow correlation of the preneoplastic increases in saturation density with genetic changes, and development of methods for demarcating fields during surgery so that they can be excised along with the tumor, thereby reducing the possibility of recurrence at the site. (shrink)

Somatic mutation plays a key role in transforming normal cells into cancerous cells. The analysis of cancer progression therefore requires the study of how point mutations and chromosomal mutations accumulate in cellular lineages. The spread of somatic mutations depends on the mutation rate, the number of cell divisions in the history of a cellular lineage, and the nature of competition between different cellular lineages. We consider how various aspects of tissue architecture and cellular competition affect the pace of (...) mutation accumulation. We also discuss the rise and fall of somatic mutation rates during cancer progression. BioEssays 26:291–299, 2004. © 2004 Wiley Periodicals, Inc. (shrink)

Rapid tissue donation (RTD) is an advancing oncology research procedure for collecting tumors, metastases, and unaffected tissue 2–6 h after death. Researchers can better determine rates of progression, response to treatment, and polymorphic differences among patients. Cancer patients may inquire about posthumous body donation for research to offer a personal contribution to research; however, there are barriers to recruiting for an RTD program. Physicians must reassure the patient that their treatment options and quality of care will not be (...) compromised due to participating in RTD. In this commentary we discuss how theories of altruism may explain cancer patients’ desire to participate in an RTD program, the ethical concerns of health care professionals and patients and the use of altruism as a recruitment strategy. We offer recommendations for examining the cultural and ethical climate of the institution prior to initiating such a program such as examining the relationship of healthcare professionals and patients, identifying ethical concerns, and examining ways to promote acceptance and buy-in across professionals, patients, and families. (shrink)

We desperately need to know more of the biological details of the onset and progression of breast cancer. The disease is of startlingly high incidence (approaching 1 in 9 women), our current therapies for the disease are inadequate once it has metastasized, and the disease is characterized by excessive morbidity and mortality.Most of the growth and differentiation of the mammary gland occurs relatively late in life: during sexual maturation, and then cyclically during pregnancy and lactation. Normal as well (...) as malignant growth is regulated by endocrine hormones as well as by local tissue factors, such as polypeptide growth factors, Cancer seems to progress as hyperplastic ductal or lobular epithelial growth, acquiring progressive genetic changes (including those of oncogenes and tumor suppressor genes) leading to clonal outgrowths of progressively more malignant cells. The nature of proliferative controls and the relevant genetic changes are the subjects of the current review. (shrink)

This article proposes that cancers can be initiated by retrotransposon (RTN) activation through changes in the transcriptional regulation of nearby genes. I first detail the hypothesis and then discuss the nature of physiological stress(es) in RTN activation; the role of DNA demethylation in the initiation and propagation of new RTN states; the connection between ageing and cancer incidence and the involvement of activated RTNs in the chromosomal aberrations that feature in cancer progression. The hypothesis neither replaces nor (...) invalidates other theories of cancer, in particular the somatic mutation theory, but helps clarify and unify much of the hitherto poorly integrated, complex phenomenology of cancer. (shrink)

According to the somatic mutation theory (SMT), cancer begins with a genetic change in a single cell that passes it on to its progeny, thereby generating a clone of malignant cells. It is strongly supported by observations of leukemias that bear specific chromosome translocations, such as Burkitt's lymphoma, in which a translocation activates the c‐myc gene, and chronic myeloid leukemia (CML), in which the Philadelphia chromosome causes production of the BCR‐ABL oncoprotein. Although the SMT has been modified and extended (...) to encompass tumor suppressor genes, epigenetic inheritance, and tumor progression through accumulation of further mutations, perhaps the strongest validation comes from the successful treatment of certain malignancies with drugs that directly target the product of the mutant gene.magnified imageDavid Vaux is at the Walter and Eliza Hall Institute and La Trobe Institute for Molecular Science, Melbourne, Australia. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Family, Friends, and Cancer:The Overwhelming Effects of Brain Cancer on a Child’s LifeLynne ScheumannOur son was diagnosed with a medulloblastoma at the old age of 13. The “lucky” part for him was his brain was almost fully developed at this age as opposed to most “medullo” patients. While this was a benefit to him it was also one of the hardest things for him.He went into surgery (...) a highly intelligent, active, and left handed boy and came out unable to move his left side, could barely speak, and very much aware of what he just lost. We, as a family, were totally unprepared for how globally this would [End Page 23] affect the rest of his life. As we spent time in the hospital I would look at the children with other types of cancer and see them walking and talking and doing their schoolwork and God forgive me I would be jealous. The fact that the cancer was in his brain, the part of his body that makes him who he is changed everything forever.He lost all of his friends because 13–year–old boys communicate best through physical activity and that was not an option for him. He still has the same personality and sense of humor, but he will not be the architect or engineer he once dreamed of being. Math, that was once so easy for him was now like a foreign language, never to be mastered again. He was able to graduate from High School and takes classes at our local Junior College in Computer Assisted Drafting, but he can only manage one or two classes a semester due to the fatigue he still suffers from.What I most worry about and wish I had been forewarned about is his long–term quality of life. Physically he has come such a long way from how he was after the resection. It was a very slow process in which the first year of rehab was slowed by the fact that one of the chemo agents causes peripheral neuropathy. He developed contractures in his ankles and needed serial casting and ankle–foot orthotics (AFO) not just on the left leg, but now the right. He was able to switch his handedness fairly easily and his left hand will always be of limited usefulness because of ataxia. I would get angry at him that he gave up on his left side so quickly until it was finally explained to me years later that the ataxia would never get better.As far as his walking ability goes he has come a long way. At first he was unable to walk and once he started rehab he went back to learning to crawl and progressed to a walker. The first time I saw him walk with the walker brought tears to my eyes. It was so much more of an event for me than when he took his first steps as a toddler. This was so much more hard fought. He never complained, just always did what was asked of him. It had to have been such hard work and also somewhat embarrassing, as he needed help to literally do everything for months. He progressed to a cane and about two years ago decided not to use that or his AFO’s. He now wears high top boots that substitute for the AFO’s but don’t make him appear disabled. Recently he decided there are times when he would be safer if he had his cane and purchased one that looks more like a hiking stick than a cane. I think he has come to terms with the fact that physically he is as good as he is going to get and works hard to maintain what he did regain. He has a trainer and goes to the gym on a regular basis with no prompting from us. I do not know if he realizes that as he ages things will be harder for him than the average person. I think in some way he is aware of that because he did decided to use the cane if safety is an issue.His... (shrink)

The dilemma of whether and how to disclose a diagnosis of cancer or of any other terminal illness continues to be a subject of worldwide interest. We present the case of a 62-year-old Japanese woman afflicted with advanced gall bladder cancer who had previously expressed a preference not to be told a diagnosis of cancer. The treating physician revealed the diagnosis to the family first, and then told the patient: "You don't have any cancer yet, but (...) if we don't treat you, it will progress to a cancer". In our analysis, we examine the role of family consent, communication patterns (including ambiguous disclosure), and advance directives for cancer disclosure in Japan. Finally, we explore the implications for Edmund Pellegrino's proposal of "something close to autonomy" as a universal good. (shrink)

There is an active research program currently underway, which treats cancer progression as an evolutionary process. This contribution investigates the ways that cancer progression is like and unlike evolution in other contexts. The aim is to take a multi-level perspective on cancer, investigating the levels at which selection may be acting, the unit or target of selection, the relative roles of selection and drift, and the idea that cancer progression may be a by-product (...) of selection at other levels of organization. (shrink)

The purpose of this paper is to present a critique of the current view that reduces cancer to a cellular problem caused by specific gene mutations and to propose, instead, that such a problem might become more intelligible, if it is understood as a phenomenon that results from the breakdown of the morphological plan or Gestalt of the organism. Such and organism, in Aristotelian terms, is characterized for presenting a specific morphe or logos (form) and for having a telos (...) (end) to fulfill. A malignant tumor represents an entity separated from both the organic logos and the organic telos. According to the basic postulates of Semiophysics – a blend of Aristotelian physics and Catastrophe Theory developed by René Thom – an organism is a source (original) form individuated by a dominant pregnance that corresponds to its morphogenetic field. Here it is suggested that cancer in aged individuals might result from the progressive exhaustion of developmental constraints that regulate the process of ontogeny, that it is expected to go from the fertilized non-differentiated zygote to the mature fully developed organism, because there is no further point ahead in the developmental pathway past the reproductive age. Cancer in young individuals (before their reproductive maturity) may then be consequence of the premature derangement of such fundamental developmental constraints. In all cases the result is the loss of morphological coherence within the organism. Thus representing a conflict between an organized morphology (the organism) and a part of such a morphology that drifts towards an amorphous state (the tumor). (shrink)

Cancer drugs are broadly classified into two categories: cytotoxic chemotherapies and targeted therapies that specifically modulate the activity of one or more proteins involved in cancer. Major advances have been achieved in targeted cancer therapies in the past few decades, which is ascribed to the increasing understanding of molecular mechanisms for cancer initiation and progression. Consequently, monoclonal antibodies and small molecules have been developed to interfere with a specific molecular oncogenic target. Targeting gain‐of‐function mutations, in (...) general, has been productive. However, it has been a major challenge to use standard pharmacologic approaches to target loss‐of‐function mutations of tumor suppressor genes. Novel approaches, including synthetic lethality and collateral vulnerability screens, are now being developed to target gene defects in p53, PTEN, and BRCA1/2. Here, we review and summarize the recent findings in cancer genomics, drug development, and molecular cancer biology, which show promise in targeting tumor suppressors in cancer therapeutics. (shrink)

Prostate cancer is the most frequently diagnosed non‐skin cancer and the third leading cause of cancer mortality in men. In the initial stages, prostate cancer is dependent on androgens for growth, which is the basis for androgen ablation therapy. However, in most cases, prostate cancer progresses to a hormone refractory phenotype for which there is no effective therapy available at present. The androgen receptor (AR) is required for prostate cancer growth in all stages, including (...) the relapsed, “androgen‐independent” tumors in the presence of very low levels of androgens. This review focuses on AR function and AR‐target genes and summarizes the major signaling pathways implicated in prostate cancer progression, their crosstalk with each other and with AR signaling. This complex network of interactions is providing a deeper insight into prostate carcinogenesis and may form the basis for novel diagnostic and therapeutic strategies. BioEssays 29:1227–1238, 2007. © 2007 Wiley Periodicals, Inc. (shrink)

Dlg (Discs large), Scrib (Scribble) and Lgl (Lethal giant larvae) are evolutionarily conserved components of a common genetic pathway that link the seemingly disparate functions of cell polarity and cell proliferation in epithelial cells. dlg, scrib and lgl have been identified as tumour suppressor genes in Drosophila, mutations of which cause similar phenotypes, involving disruption of cell polarity and neoplastic overgrowth of tissues. The molecular mechanisms by which Dlg, Scrib and Lgl proteins regulate cell proliferation are not clear, but there (...) is some evidence that epithelial polarisation is required for this regulation. Dlg, Scrib and Lgl are highly conserved between human and Drosophila, and we discuss evidence that these proteins also play a role in cancer progression in humans. BioEssays 25:542–553, 2003. © 2003 Wiley Periodicals, Inc. (shrink)

Public health aims to provide universal safety and progressive opportunities to populations to realise their highest level of health through prevention of disease, its progression or transmission. Screening asymptomatic individuals to detect early unapparent conditions is an important public health intervention strategy. It may be designed to be compulsory or voluntary depending on the epidemiological characteristics of the disease. Integrated screening, including for both syphilis and cancer of the cervix, is a core component of the national reproductive health (...) program in Kenya. Screening for syphilis is compulsory while it is voluntary for cervical cancer. Participants’ perspectives of either form of screening approach provide the necessary contextual information that clarifies mundane community concerns. (shrink)

Inflamm‐aging is a relatively new terminology used to describe the age‐related increase in the systemic pro‐inflammatory status of humans. Here, we represent inflamm‐aging as a breakdown in the multi‐shell cytokine network, in which stem cells and stromal fibroblasts (referred to as the stem cell niche) become pro‐inflammatory cytokine over‐expressing cells due to the accumulation of DNA damage. Inflamm‐aging self‐propagates owing to the capability of pro‐inflammatory cytokines to ignite the DNA‐damage response in other cells surrounding DNA‐damaged cells. Macrophages, the major cellular (...) player in inflamm‐aging, amplify the phenomenon, by broadcasting pro‐inflammatory signals at both local and systemic levels. On the basis of this, we propose that inflamm‐aging is a major contributor to the increase in cancer incidence and progression in aged people. Breast cancer will be presented as a paradigmatic example for this relationship. (shrink)

It now appears that the molecular events associated with the mitogenic action of growth factors are also the events perturbed in neoplastic lesions. This review outlines the relevance of our recent progress in the biochemistry of growth factors and their receptors to the induction and maintenance of the neoplastic state.

In humans, the intestine is the major reservoir of microbes. Although the intestinal microbial community exists in a state of homeostasis called eubiosis, environmental and genetics factors can lead to microbial perturbation or dysbiosis, a state associated with various pathologies including inflammatory bowel diseases (IBD) and colorectal cancer (CRC). Dysbiotic microbiota is thought to contribute to the initiation and progression of CRC. At the opposite end of the spectrum, two recently published studies in Science reveal that the microbiota (...) is essential for chemotherapeutic drug efficacy, suggesting a beneficial microbial function in cancer management. The dichotomy between the beneficial and detrimental roles of the microbiota during cancer initiation, progression, and treatment emphasize the interwoven relationship between bacteria and cancer. Moreover, these findings suggest that the microbiota could be considered as a therapeutic target, not only at the level of cancer prevention, but also during management, i.e. by enhancing the efficacy of chemotherapeutics. (shrink)

Understanding the clinical significance of variants associated with hereditary cancer risk requires access to a pooled data resource or network of resources—a “cancer gene variant commons”—incorporating representative, well-characterized genetic data, metadata, and, for some purposes, pathways to case-level data. Several initiatives have invested significant resources into collecting and sharing cancer gene variant data, but further progress hinges on identifying and addressing unresolved policy issues. This commentary provides insights from a modified policy Delphi process involving experts from a (...) range of stakeholder groups involved in the data-sharing ecosystem. In particular, we describe policy issues and options generated by Delphi participants in five domains critical to the development of an effective cancer gene variant commons: incentives, financial sustainability, privacy and security, equity, and data quality. Our intention is to stimulate wider discussion and lay a foundation for further work evaluating policy options more in-depth and mapping them to those who have the power to bring about change. Addressing issues in these five domains will contribute to a cancer gene variant commons that supports better care for at-risk and affected patients, empowers patient communities, and advances research on hereditary cancers. (shrink)

The question as to why some hosts can eradicate their tumors while others succumb to tumor‐progression remains unanswered. Here, a provocative concept is proposed that intrinsic differences in the T cell receptor (TCR) repertoire of individuals may influence the outcome of anti‐tumor immunity by affecting the frequency and/or variety of tumor‐reactive CD8 and/or CD4 tumor‐infiltrating lymphocytes. This idea implicates that the TCR repertoire in a given patient might not provide sufficiently different TCR clones that can recognize tumor antigens, namely, (...) “a hole in the TCR repertoire” might exist. This idea may provide a novel perspective to further dissect the mechanisms underlying heterogeneous anti‐tumor immune responses in different hosts. Besides tumor‐intrinsic heterogeneity and host microbiome, the various factors that may constantly shape the dynamic TCR repertoire are also discussed. Elucidating mechanistic differences in different individuals’ immune systems will allow to better harness immune system to design new personalized cancer immunotherapy. (shrink)

Carbon and nitrogen are essential elements for life. Glucose as a carbon source and glutamine as a nitrogen source are important nutrients for cell proliferation. About 100 years ago, it was discovered that cancer cells that have acquired unlimited proliferative capacity and undergone malignant evolution in their host manifest a cancer‐specific remodeling of glucose metabolism (the Warburg effect). Only recently, however, was it shown that the metabolism of glutamine‐derived nitrogen is substantially shifted from glutaminolysis to nucleotide biosynthesis during (...) malignant progression of cancer—which might be referred to as a “second” Warburg effect. In this review, address the mechanism and relevance of this metabolic shift of glutamine‐derived nitrogen in human cancer. We also examine the clinical potential of anticancer therapies that modulate the metabolic pathways of glutamine‐derived nitrogen. This shift may be as important as the shift in carbon metabolism, which has long been known as the Warburg effect. (shrink)

In the nearly 40 years since implementation of federal regulations governing the protection of human participants in research, the number of clinical studies has grown exponentially. These studies have become more complex, with multisite trials now common, and there is increasing use of archived biospecimens and related data, including genomics data. In addition, growing emphasis on targeted cancer therapies requires greater collaboration and sharing of research data to ensure that rare patient subsets are adequately represented. Electronic records enable more (...) extensive data collection and mining, but also raise concerns about the potential for inappropriate or unauthorized use of data, bringing patient protections into a new landscape. There are also long-standing concerns about the processes and forms used to obtain informed consent from patients participating in clinical studies. These changes and challenges raise new ethical and practical questions for the oversight of clinical studies, and for protecting patients and their health information in an efficient manner that does not compromise the progress of biomedical research. Contemporary Issues for Protecting Patients in Cancer Research is the summary of a workshop convened by the National Cancer Policy Forum of the Institute of Medicine in February 2014 to explore contemporary issues in human subjects protections as they pertain to cancer research, with the goal of identifying potential relevant policy actions. Clinical researchers, government officials, members of Institutional Review Boards, and patient advocates met to discuss clinical cancer research and oversight. This report examines current regulatory provisions that may not adequately protect patients or may be hindering research, and discusses potential strategies and actions to address those challenges. (shrink)

Small non‐coding RNAs (microRNAs or miRs) represent one of the most fertile areas of cancer research and recent advances in the field have prompted us to reconsider the traditional concept of cancer. Some miRs exert negative control over the expression of numerous oncoproteins in normal cells and consequently their deregulation is believed to be an important mechanism underlying cancer development and progression. Owing to their distinct patterns of expression associated with cancer type, remarkable stability and (...) presence in blood and other body fluids, miRs are considered to be highly promising cancer biomarkers. The identification of “miR signatures” associating cancer cell phenotypes with disease outcome and specific risk factor exposures will undoubtedly open new avenues for early diagnosis and therapy of cancer, as well as for the development of novel strategies for cancer prevention. (shrink)