microRNAs in breast cancer: regulatory roles governing the hallmarks of cancer

A large number of etiological factors and the complexity of breast cancers present challenges for prevention and treatment. Recently, the emergence of microRNAs (miRNAs) as cancer biomarkers has added an extra dimension to the ‘molecular signatures’ of breast cancer. Bioinformatic analyses indicate that each miRNA can regulate hundreds of target genes and could serve functionally as ‘oncogenes’ or ‘tumour suppressor’ genes, and co‐ordinate multiple cellular processes relevant to cancer progression. A number of studies have shown that miRNAs play important roles in breast tumorigenesis, metastasis, proliferation and differentiation of breast cancer cells. This review provides a comprehensive overview of miRNAs with established functional relevance in breast cancer, their established target genes and resulting cellular phenotype. The role and application of circulating miRNAs in breast cancer is also discussed. Furthermore, we summarize the role of miRNAs in the hallmarks of breast cancer, as well as the possibility of using miRNAs as potential biomarkers for detection of breast cancer.     

Aromatase inhibitors continue their ATAC on tamoxifen

The breast cancer drug tamoxifen, the best-known and most widely prescribed anticancer drug in the world, is facing a stiff challenge from an exciting group of compounds called aromatase inhibitors. ‘Tamoxifen is under threat,’ says Anthony Howell, Professor of Medical Oncology at Manchester's Christie Hospital, and Principal Investigator of the largest breast cancer trial ever undertaken. The initial results of this trial suggest that for postmenopausal women, the aromatase inhibitor anastrozole (Arimidex®) is more successful than tamoxifen as an adjuvant (i.e. treatment given to patients after surgery to prevent their cancer returning). ‘If this result holds up, which I think it will undoubtedly, tamoxifen will be ousted from its first-line setting for postmenopausal women,’ he says.     

Breast-conserving therapy versus modified radical mastectomy: socioeconomic status determines who receives what--results from case-control study in Tianjin, China

Background: Despite anecdotal evidence linking socioeconomic status and choices on surgical management in breast cancer patients in China, no scientific evaluations have ever been conducted. The objective of this study was to evaluate patient factors that influence patients’ treatment options between breast cancer patients receiving breast-conserving therapy (BCT) and modified radical mastectomy (MRM). Methods: A total of 268 stage I–II breast cancer patients treated with BCT in Tianjin Cancer Hospital, from January 2005 to January 2007, were compared with 200 randomly selected breast cancer patients (controls) treated with MRM. A personal health questionnaire (PHQ) was used to assess the factors that may affect the surgical decision making. Chi-squared test and multiple logistic regressions were used to examine factors associated with BCT. Results: BCT patients who were younger and were more likely to live in urban areas had medical insurance, higher levels of education and family income. Patients with medical insurance coverage were approximately six times more likely to receive BCT than patients without medical insurance after controlling for other potentially confounding factors. Similar results were also observed for family income. The observed differences cannot be explained by clinical aspects of their disease, such as tumor stage, estrogen receptor, and lymph node involvement. Conclusion: Breast cancer patients’ socioeconomic status, rather than their clinical condition, is the predominant factor in determining whether a breast cancer patient receives BCT or not. These results provide a snapshot on how socioeconomic status influences cancer care provision in China. Future efforts should be made towards reducing discrepancies in treatment options for cancer patients caused by social class and socioeconomic status.     

Wild justice and fair play: cooperation,forgiveness, and morality in animals

In this paper I argue that we can learn much about ‘wild justice’ and the evolutionary origins of social morality – behaving fairly – by studying social play behavior in group-living animals, and that interdisciplinary cooperation will help immensely. In our efforts to learn more about the evolution of morality we need to broaden our comparative research to include animals other than non-human primates. If one is a good Darwinian, it is premature to claim that only humans can be empathic and moral beings. By asking the question ‘What is it like to be another animal?’ we can discover rules of engagement that guide animals in their social encounters. When I study dogs, for example, I try to be a ‘dogocentrist’ and practice ‘dogomorphism.’ My major arguments center on the following ‘big’ questions: Can animals be moral beings or do they merely act as if they are? What are the evolutionary roots of cooperation, fairness, trust, forgiveness, and morality? What do animals do when they engage in social play? How do animals negotiate agreements to cooperate, to forgive, to behave fairly, to develop trust? Can animals forgive? Why cooperate and play fairly? Why did play evolve as it has? Does ‘being fair’ mean being more fit – do individual variations in play influence an individual's reproductive fitness, are more virtuous individuals more fit than less virtuous individuals? What is the taxonomic distribution of cognitive skills and emotional capacities necessary for individuals to be able to behave fairly, to empathize, to behave morally? Can we use information about moral behavior in animals to help us understand ourselves? I conclude that there is strong selection for cooperative fair play in which individuals establish and maintain a social contract to play because there are mutual benefits when individuals adopt this strategy and group stability may be also be fostered. Numerous mechanisms have evolved to facilitate the initiation and maintenance of social play to keep others engaged, so that agreeing to play fairly and the resulting benefits of doing so can be readily achieved. I also claim that the ability to make accurate predictions about what an individual is likely to do in a given social situation is a useful litmus test for explaining what might be happening in an individual's brain during social encounters, and that intentional or representational explanations are often important for making these predictions.     

Status Signalling by Parus major: An Experiment in Deception

The ‘social control’ and ‘incongruence’ hypotheses, first put forward by ROHWER (1977) to explain how attempted ‘deceit’ status signalling is kept in check among winter-flocking birds, were tested under semi-natural conditions for Parus major. This species signals its social status by the width of its breast stripe. The lowest-ranked male in experimental flocks, each made up of four individuals, was manipulated in one of three ways: 1) the status signal was altered by painting the breast stripe to make it broader; 2) agonistic behaviour was altered by injecting testosterone; 3) both status signal and behaviour were manipulated. A study of the outcome of subsequent agonistic encounters by these birds revealed that the status of the manipulated individuals only rose when both their behaviour and status signal were altered. This indicates that the ‘social control’ hypothesis must be rejected, but not the ‘incongruence’ hypothesis.     

Boldness and Information Use in Three‐Spined Sticklebacks

In foraging groups, individuals may utilise information from their social environment to aid decision making when choosing where to search for food. Little work has looked at the costs or benefits of behavioural differences, such as consistent individual variation in boldness, with respect to learning ability. Here, we investigate the response of three‐spined stickleback (Gasterosteus aculeatus) to ‘social cues’, ‘local enhancement’ and ‘public information’ during foraging tasks. Our results confirm previous work suggesting that this species responds to social cues and local enhancement but not public information. Variation in boldness did not affect the use of different types of information. However, time taken to make a choice and reach a patch varied between fish with different levels of boldness. Contrary to expectation, shy fish were the more variable individuals, having a greater range of reaction times when responding to the tasks. This suggests that individual behavioural differences still play a role when utilising information obtained from the environment and may influence the relative benefits that could result in different contexts.     

Applications of Personalized Estimates of Absolute Breast Cancer Risk

Absolute risk is the probability that a given health outcome will be observed in a defined time period in the presence of competing causes of death. In this commentary I discuss some applications of models of absolute breast cancer risk that account for a woman’s particular risk factors. Such models can be useful in counseling by giving perspective on the level of risk, and as an aid to weighing risks and benefits, as in deciding whether or not to take tamoxifen to prevent breast cancer. Absolute risk models also have applications in public health, such as in designing intervention trials to prevent breast cancer and in assessing the potential reductions in absolute risk of disease that might result from reducing exposures. Other potential public health applications that require models with high discriminatory accuracy are to identify “high risk” subsets of the population that might benefit from a preventive intervention or screening, or to rank members of the population on risk to allocate preventive resources under cost constraints.     

Breast cancer--a woman's perspective.

This paper is bound to arouse controversy. It already has. No article in this special issue has been more thoroughly reviewed or had more widely divergent opinions. Some reviewers thought it expressed unrelieved anger; others felt it described the experience, perceptions, and feelings of many women with breast cancer. The paper seemed important to publish, however, because breast cancer is the second most common tumor occurring in American women. It is important to note that the author is a successful teacher and health professional who has a full and active family and social life. She describes encounters with breast cancer in an uncommonly fervent and articulate way. These encounters have clearly left deep scars. The essay is not scientific and not balanced in this issue by a paper by a women who had a wonderful experience with breast cancer. Such a paper may never be written. Read on!     

Local Breast Cancer Spatial Patterning: A Tool for Community Health Resource Allocation to Address Local Disparities in Breast Cancer Mortality

Despite available demographic data on the factors that contribute to breast cancer mortality in large population datasets, local patterns are often overlooked. Such local information could provide a valuable metric by which regional community health resources can be allocated to reduce breast cancer mortality. We used national and statewide datasets to assess geographical distribution of breast cancer mortality rates and known risk factors influencing breast cancer mortality in middle Tennessee. Each county in middle Tennessee, and each ZIP code within metropolitan Davidson County, was scored for risk factor prevalence and assigned quartile scores that were used as a metric to identify geographic areas of need. While breast cancer mortality often correlated with age and incidence, geographic areas were identified in which breast cancer mortality rates did not correlate with age and incidence, but correlated with additional risk factors, such as mammography screening and socioeconomic status. Geographical variability in specific risk factors was evident, demonstrating the utility of this approach to identify local areas of risk. This method revealed local patterns in breast cancer mortality that might otherwise be overlooked in a more broadly based analysis. Our data suggest that understanding the geographic distribution of breast cancer mortality, and the distribution of risk factors that contribute to breast cancer mortality, will not only identify communities with the greatest need of support, but will identify the types of resources that would provide the most benefit to reduce breast cancer mortality in the community.     

Modelling the Dynamics of Crystal Meth (‘Tik’) Abuse in the Presence of Drug-Supply Chains in South Africa

Substance abuse remains a global problem, with immense health and social consequences. Crystal meth, known as ‘tik’ in South Africa, is a growing problem, and its supply chains have equally grown due to increased numbers of ‘tik’ users, especially in the Western Cape province of South Africa. We consider a model for ‘tik’ use that tracks drug-supply chains, and accounts for rehabilitation and amelioration for the addicted. We analyse the model and show that it has a unique drug-free equilibrium. We prove that the drug-free equilibrium is globally stable when the reproduction number is less than one. We also consider both slow and fast dynamics, and show that there is a unique drug-persistent equilibrium when the reproduction number exceeds one. The model is fitted to data on ‘tik’ users in rehabilitation in the Western Cape province. A sensitivity analysis reveals that the parameters with the most control over the epidemic are the quitting rate of light-drug users and the person-to-person contact rate between susceptible individuals and ‘tik’ users. This suggests that programs aimed at light-drug users that encourage them to quit will be significantly more effective than targeting hard-drug users, either in quitting or in rehabilitation. Similarly, the person-to-person contact rate may be reduced by social programs that raise awareness of the dangers of ‘tik’ use and discourage light users from recruiting others.     

Chronotype and postmenopausal breast cancer risk among women in the California Teachers Study

ABSTRACT

Chronotype is the behavioral manifestation of an individual’s underlying circadian rhythm, generally characterized by one’s propensity to sleep at a particular time during the 24 hour cycle. Evening chronotypes (“night owls”) generally suffer from worse physical and mental health compared to morning chronotypes (“morning larks”) – for reasons that have yet to be explained. One hypothesis is that evening chronotypes may be more susceptible to circadian disruption, a condition where the coordinated timing of biologic processes breaks down. The role of chronotype as an independent or modifying risk factor for cancer has not been widely explored. The objective of the current study was to evaluate the risk of breast cancer associated with chronotype in a case-control study nested within the California Teachers Study (CTS) cohort. The study population consisted of 39686 post-menopausal CTS participants who provided information on chronotype by completing a questionnaire in 2012–2013. 2719 cases of primary invasive breast cancer diagnosed from 1995/1996 through completion of the chronotype questionnaire were identified by linkage of the CTS to the California Cancer Registry. 36967 CTS participants who had remained cancer-free during this same time period served as controls. Chronotype was ascertained by responses to an abbreviated version of the Horne-Ostberg Morningness-Eveningness Questionnaire (MEQ) and was characterized into five categories: definite morning, more morning than evening, neither morning or evening, more evening than morning, definite evening. Multivariable unconditional logistic regression analyses were performed to estimate the odds ratios (ORs) and 95% confidence intervals (95% CIs) for each of the chronotypes, adjusted for established breast cancer risk factors. Compared to definite morning types, definite evening types had an increased risk of breast cancer with elevated ORs that were statistically significant in both the crude (OR = 1.24, 95% CI: 1.10–1.40) and fully-adjusted models (OR = 1.20, 95% CI: 1.06–1.35). The risk estimates in the fully-adjusted model for all other chronotypes did not significantly differ from one. These results suggest that evening chronotype may be an independent risk factor for breast cancer among a population of women who are not known to have engaged in any substantial night shift work. Further research in other populations of non-shift workers is warranted.     

Discovery of pathway biomarkers from coupled proteomics and systems biology methods

Background

Breast cancer is worldwide the second most common type of cancer after lung cancer. Plasma proteome profiling may have a higher chance to identify protein changes between plasma samples such as normal and breast cancer tissues. Breast cancer cell lines have long been used by researches as model system for identifying protein biomarkers. A comparison of the set of proteins which change in plasma with previously published findings from proteomic analysis of human breast cancer cell lines may identify with a higher confidence a subset of candidate protein biomarker.

Results

In this study, we analyzed a liquid chromatography (LC) coupled tandem mass spectrometry (MS/MS) proteomics dataset from plasma samples of 40 healthy women and 40 women diagnosed with breast cancer. Using a two-sample t-statistics and permutation procedure, we identified 254 statistically significant, differentially expressed proteins, among which 208 are over-expressed and 46 are under-expressed in breast cancer plasma. We validated this result against previously published proteomic results of human breast cancer cell lines and signaling pathways to derive 25 candidate protein biomarkers in a panel. Using the pathway analysis, we observed that the 25 “activated” plasma proteins were present in several cancer pathways, including ‘Complement and coagulation cascades’, ‘Regulation of actin cytoskeleton’, and ‘Focal adhesion’, and match well with previously reported studies. Additional gene ontology analysis of the 25 proteins also showed that cellular metabolic process and response to external stimulus (especially proteolysis and acute inflammatory response) were enriched functional annotations of the proteins identified in the breast cancer plasma samples. By cross-validation using two additional proteomics studies, we obtained 86% and 83% similarities in pathway-protein matrix between the first study and the two testing studies, which is much better than the similarity we measured with proteins.

Conclusions

We presented a ‘systems biology’ method to identify, characterize, analyze and validate panel biomarkers in breast cancer proteomics data, which includes 1) t statistics and permutation process, 2) network, pathway and function annotation analysis, and 3) cross-validation of multiple studies. Our results showed that the systems biology approach is essential to the understanding molecular mechanisms of panel protein biomarkers.

     

Identification of single chain antibodies to breast cancer stem cells using phage display

Recent evidence suggests that most malignancies are driven by “cancer stem cells” sharing the signature characteristics of adult stem cells: the ability to self renew and to differentiate. Furthermore these cells are thought to be quiescent, infrequently dividing cells with a natural resistance to chemotherapeutic agents. These studies theorize that therapies, which effectively treat the majority of tumor cells but ‘miss’ the stem cell population, will fail, while therapies directed at stern cells can potentially eradicate tumors. In breast cancer, researchers have isolated ‘breast cancer stem cells’ capable of recreating the tumor in vivo and in vitro. Generated new tumors contained both additional numbers of cancer stem cells and diverse mixed populations of cells present in the initial tumor, supporting the intriguing self‐renewal and differentiation characteristics. In the present study, an antibody phage library has been used to search for phage displayed‐single chain antibodies (scFv) with selective affinity to specific targets on breast cancer stem cells. We demonstrate evidence of two clones binding specifically to a cancer stem cell population isolated from the SUMl59 breast cancer cell line. These clones had selective affinity for cancer stem cells and they were able to select cancer stem cells among a large population of non‐stem cancer cells in paraffin‐embedded sections. The applicability of these clones to paraffin sections and frozen tissue specimens made them good candidates to be used as diagnostic and prognostic markers in breast cancer patient samples taking into consideration the cancer stern cell concept in tumor biology. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009     

Scaffold stiffness influences breast cancer cell invasion via EGFR-linked Mena upregulation and matrix remodeling

Clinically, increased breast tumor stiffness is associated with metastasis and poorer outcomes. Yet, in vitro studies of tumor cells in 3D scaffolds have found decreased invasion in stiffer environments. To resolve this apparent contradiction, MDA-MB-231 breast tumor spheroids were embedded in ‘low’ (2 kPa) and ‘high’ (12 kPa) stiffness 3D hydrogels comprised of methacrylated gelatin/collagen I, a material that allows for physiologically-relevant changes in stiffness while matrix density is held constant. Cells in high stiffness materials exhibited delayed invasion, but more abundant actin-enriched protrusions, compared to those in low stiffness. We find that cells in high stiffness had increased expression of Mena, an invadopodia protein associated with metastasis in breast cancer, as a result of EGFR and PLCγ1 activation. As invadopodia promote invasion through matrix remodeling, we examined matrix organization and determined that spheroids in high stiffness displayed a large fibronectin halo. Interestingly, this halo did not result from increased fibronectin production, but rather from Mena/α5 integrin dependent organization. In high stiffness environments, FN1 knockout inhibited invasion while addition of exogenous cellular fibronectin lessened the invasion delay. Analysis of fibronectin isoforms demonstrated that EDA-fibronectin promoted invasion and that clinical invasive breast cancer specimens displayed elevated EDA-fibronectin. Combined, our data support a mechanism by which breast cancer cells respond to stiffness and render the environment conducive to invasion. More broadly, these findings provide important insight on the roles of matrix stiffness, composition, and organization in promoting tumor invasion.     

Envy and egalitarianism in Aboriginal Australia: An integrative approach

The word ‘envy’ directs attention to feelings and cognitions that are especially important sources of information in our complicated sociality. As it is delimited by philosophers, economists, psychologists and others, envy is conceptually nested within a family that includes evil eye beliefs, inequity aversion, strong reciprocity and social comparison. Although the accumulation of work in these areas is substantial, anthropological treatments of envy are rare. Given repeated assertions of envy's universality and its potential importance for understanding widespread aspects of the human condition, a comparative eye seems essential. I present an account of ‘jealous’ in Aboriginal Australia via a framework that casts emotions as emerging from the interaction of psychobiological and sociocultural processes. According to this perspective, ‘envy’ should not be regarded as an invariant human condition but rather as a Western version of what, in a more generic human form, may both defend the individual and the larger sociality.     

Context-dependent model-based biases in cultural transmission: children's imitation is affected by model age over model knowledge state

Many animals, including humans, acquire information through social learning. Although such information can be acquired easily, its potential unreliability means it should not be used indiscriminately. Cultural ‘transmission biases’ may allow individuals to weigh their reliance on social information according to a model's characteristics. In one of the first studies to juxtapose two model-based biases, we investigated whether the age and knowledge state of a model affected the fidelity of children's copying. Eighty-five 5-year-old children watched a video demonstration of either an adult or child, who had professed either knowledge or ignorance regarding a tool-use task, extracting a reward from that task using both causally relevant and irrelevant actions. Relevant actions were imitated faithfully by children regardless of the model's characteristics, but children who observed an adult reproduced more irrelevant actions than those who observed a child. The professed knowledge state of the model showed a weaker effect on imitation of irrelevant actions. Overall, children favored the use of a ‘copy adults’ bias over a ‘copy task-knowledgeable individual’ bias, even though the latter could potentially have provided more reliable information. The use of such social learning strategies has significant implications for understanding the phenomenon of imitation of irrelevant actions (overimitation), instances of maladaptive information cascades, and cumulative culture.     

Gaussian Dropout Based Stacked Ensemble CNN for Classification of Breast Tumor in Ultrasound Images

ObjectiveBreast cancer and breast tumors have been considered to be the most pervasive form of cancer in medical practice. Breast tumors are life-threatening to women, and their early detection could save lives with the proper treatment. Physical methods for detection of Breast Cancer are time-consuming and often prone to a misdiagnosis at classifying tumors. Recent trends in radiological imaging have significantly improved the efficiency and veracity of breast tumor classification. Artificial intelligence techniques could be used as an automated detection and classification system.Materials and methodsIn this research, we propose a novel configuration of a Stacking Ensemble with custom Convolutional Neural Network architectures to classify breast tumors from ultrasound images into ‘Normal’, ‘Benign’, and ‘Malignant’ categories.ResultsAfter thorough experimentation, our ensemble has performed with an accuracy, f1-score, precision, and recall of 92.15%, 92.21%, 92.26%, 92.17% respectively.ConclusionThe presented ensemble leverages three Stacked Feature Extractors coupled with a characteristic meta-learner to provide an overall balanced classification performance, with better accuracy and lower false positives. The architecture works in association with gaussian dropout layers to improve the computation and an alternative pooling scheme to retain essential features.     

What is the role of family in promoting faecal occult blood test screening? Exploring physician,average-risk individual,and family perceptions

Background: Although the number of Canadians being screened for colon cancer is rising, only 40% of Canadians aged 50 years or older reported they had engaged in faecal occult blood test (FOBT) screening as recommended. The notion of ‘partnerships’ that is inclusive of physicians, individuals at average-risk for colorectal cancer, and influential family members is receiving more attention in primary health care literature and policy on promoting health maintenance behaviours. To the best of our knowledge there are no studies that have taken a tripartite approach in describing perspectives of these three key stakeholders on the role of family in promoting adherence to FOBT. The aim of this study was to address the gap in understanding the perspectives of primary care physicians, individuals at average-risk for colorectal cancer, and family on family role in promoting adherence to FOBT screening. Method: We employed a qualitative design and conducted semi-structured interviews with 15 physicians, 27 patients at average-risk for colorectal cancer, and 19 family members or friends from urban and rural Manitoba, Canada between October 2008 and March 2010. Interviews were audio-recorded, transcribed verbatim, and analysed using content analysis and constant comparative techniques. Results: While physicians described a clear role for family in managing chronic disease or dealing with acute or serious illness, they identified barriers in working with family to promote FOBT screening: lack of time, privacy and confidentiality concerns, and family dynamics. Conversely, patients and family described instrumental, emotional, informational, and appraisal roles that family play in promoting FOBT outside medical encounters. Conclusion: Adherence to colorectal cancer screening is based on supportive ‘patient–physician’ dialogue that is separate from assistive ‘patient–family member’ relations. Further research is required to explore social support mechanisms involving family members outside medical encounters that hold promise in boosting self-efficacy, overcoming barriers, and gaining positive reinforcement for individuals at average-risk when making the decision to engage in FOBT.