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mp3 file (9 MB). In the June edition of the Cancer Discovery podcast, Science Writer Elizabeth McKenna talks with Kornelia Polyak about her paper, which uses a combined experimental and computational approach to reveal that the loss of wild-type BRCA1 may not be the first event in the majority of BRCA1-associated breast tumors and may not be present in all cancer cells within tumors.

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PDF file - 171K, Optimization and validation of the techniques used.

PDF file - 149K, Evolutionary paths and BRCA1 expression in breast tumors.

BRCA1-associated breast tumors display loss of BRCA1 and frequent somatic mutations of PTEN and TP53. Here we describe the analysis of BRCA1, PTEN, and p53 at the single cell level in 55 BRCA1-associated breast tumors and computational methods to predict the relative temporal order of somatic events, on the basis of the frequency of cells with single or combined alterations. Although there is no obligatory order of events, we found that loss of PTEN is the most common first event and is associated with basal-like subtype, whereas in the majority of luminal tumors, mutation of TP53 occurs first and mutant PIK3CA is rarely detected. We also observed intratumor heterogeneity for the loss of wild-type BRCA1 and increased cell proliferation and centrosome amplification in the normal breast epithelium of BRCA1 mutation carriers. Our results have important implications for the design of chemopreventive and therapeutic interventions in this high-risk patient population.Significance: Defining the temporal order of tumor-driving somatic events is critical for early detection, risk stratification, and the design of chemopreventive therapies. Our combined experimental and computational approach reveal that the loss of wild-type BRCA1 may not be the first event in the majority of BRCA1-associated breast tumors and may not be present in all cancer cells within tumors. Cancer Discov; 2(6); 503–11. ©2012 AACR.This article is highlighted in the In This Issue feature, p. 473

The genomic complexity and heterogeneity of high-grade serous ovarian cancer (HGSOC) has hampered the realisation of successful therapies and effective personalised treatment is an unmet clinical need. Here we show that primary HGSOC spheroid models can be used to predict drug response and use them to demonstrate that somatic copy number alterations (SCNAs) in frequently amplified HGSOC cancer genes significantly correlate with gene expression and drug response. These genes are often located in areas of the genome with frequent clonal SCNAs. MYC chromosomal copy number is associated with ex-vivo and clinical response to paclitaxel and ex-vivo response to mTORC1/2 inhibition. Activation of the mTOR survival pathway in the context to MYC-amplified HGSOC is mostly due to increased prevalence of SCNAs in genes from the PI3K pathway. These results suggest that SCNAs encompassing driver genes could be used to inform therapeutic response in the context of clinical trials testing personalised medicines.

Background PTEN loss is a putative driver in histotypes of ovarian cancer (high-grade serous (HGSOC), endometrioid (ENOC), clear cell (CCOC), mucinous (MOC), low-grade serous (LGSOC)). We aimed to characterise PTEN expression as a biomarker in epithelial ovarian cancer in a large population-based study. Methods Tumours from 5400 patients from a multicentre observational, prospective cohort study of the Ovarian Tumour Tissue Analysis Consortium were used to evaluate associations between immunohistochemical PTEN patterns and overall survival time, age, stage, grade, residual tumour, CD8+ tumour-infiltrating lymphocytes (TIL) counts, expression of oestrogen receptor (ER), progesterone receptor (PR) and androgen receptor (AR) by means of Cox proportional hazard models and generalised Cochran–Mantel–Haenszel tests. Results Downregulation of cytoplasmic PTEN expression was most frequent in ENOC (most frequently in younger patients; p value = 0.0001) and CCOC and was associated with longer overall survival in HGSOC (hazard ratio: 0.78, 95% CI: 0.65–0.94, p value = 0.022). PTEN expression was associated with ER, PR and AR expression (p values: 0.0008, 0.062 and 0.0002, respectively) in HGSOC and with lower CD8 counts in CCOC (p value p value = 0.019) and associated with higher CD8 counts (p value = 0.0016). Conclusions PTEN loss is a frequent driver in ovarian carcinoma associating distinctly with expression of hormonal receptors and CD8+ TIL counts in HGSOC and CCOC histotypes.

Background The extreme genomic heterogeneity of high-grade serous ovarian carcinoma (HGSOC) is a major barrier to precision medicine approaches. We have developed mutational signature analysis from shallow whole genome sequencing (sWGS) for molecular stratification and therapeutic prediction. PARP inhibitor therapy has significant survival advantage for women with germline BRCA1/2 mutations, but treatments and predictive biomarkers for women without homologous recombination deficiency have not been developed. MYC amplification is the most common driver in HGSOC, present in 42% of the TCGA cases. The best responder from the phase 1 trial of AZD2014 (dual m-TORC1/2 inhibitor) and paclitaxel in HGSOC had a mutation in MYC and we have hypothesised that biosynthetic effects of MYC are mediated through the mTOR pathway and blocked by AZD2014 perturbation. Methods Primary ovarian cancer spheroids were purified from 28 human ascites and profiled with sWGS. Ex-vivo therapeutic response was measured to four standard of care chemotherapeutic agents and eight inhibitors targeting nodal points of the PI3K and DNA damage repair pathways. RNA seq data from the TCGA HGSOC cohort was used to establish the genes whose expression was highly correlated with the expression of MYC. Results Ex-vivo assays were predictive of first-line clinical response to chemotherapy agents (P Conclusions Our results suggest that therapeutic strategies combining paclitaxel and inhibition of mTOR pathway can be used as personalised treatment in the context of MYC-amplified HGSOC. We are currently examining gene expression after AZD2014 pertubation in HGSOC models and performing the genomic analysis of cases from the phase 1 trial of AZD2014 and paclitaxel. Legal entity responsible for the study The authors. Funding Academy of Medical Sciences, Addenbrookes Charitable Trust, Cancer Research UK, University of Cambridge. Disclosure F.C. Martins: Research grant / Funding (self), The Clinical Lectureship from the Experimental Medicine Initiative is partly funded by AstraZeneca: AstraZeneca. All other authors have declared no conflicts of interest.

Objective: The objectives of the study were to highlight some of the differences in training systems and opportunities for training in gynecologic oncology across Europe and to draw attention to steps that can be taken to improve training prospects and experiences of European trainees in gynecologic oncology. Methods: The European Network of Young Gynaecological Oncologists national representatives from 34 countries were asked to review and summarize the training system in their countries of origin and fulfill a mini-questionnaire evaluating different aspects of training. We report analysis of outcomes of the mini-questionnaire and subsequent discussion at the European Network of Young Gynaecological Oncologists national representatives Asian Pacific Organization for Cancer Prevention meeting in Istanbul (April 2010). Results: Training fellowships in gynecologic oncology are offered by 18 countries (53%). The median duration of training is 2.5 years (interquartile range, 2.0-3.0 years). Chemotherapy administration is part of training in 70.5% (24/34) countries. Most of the countries (26/34) do not have a dedicated national gynecologic-oncology journal. All trainees reported some or good access to training in advanced laparoscopic surgical techniques, whereas 41% indicated no access, and 59% some access to training opportunities in robotic surgery. European countries were grouped into 3 different categories on the basis of available training opportunities in gynecologic oncology: well-structured, moderately structured, and loosely structured training systems. Conclusions: There is a need for further harmonization and standardization of training programs and structures in gynecologic oncology across Europe. This is of particular relevance for loosely structured countries that lag behind the moderately structured and well-structured ones.

GoalsExpression of GLUT-1 and transglutaminase 2 is increased in aggressive breast cancer, whereas claudin-1, which is expressed in normal tissues, is absent in such tumors. This experimental study was undertaken to establish the aggressiveness and prognosis of DMBA-induced mammary tumors in female Wistar rats based on the assessment of these markers.Materials and methodsThe rats were divided into two groups, a control group (n = 70) and a chemoprevention group (n = 70). Breast tumors were induced in both groups by administration of 7,12-dimethylbenz[a]anthracene (DMBA). The chemoprevention group also received alpha-tocopherol and a solution of micronutrients containing ascorbic acid and selenium. Neoplastic lesions of both groups were randomly selected for immunohistochemical assessment of the expression of GLUT-1, transglutaminase 2 and claudin-1.ResultsA higher proportion of mammary tumors expressed GLUT-1 and transglutaminase 2 in the chemoprevention group. Claudin-1 expression was absent in all tumors of both groups.ConclusionsThese results are suggestive of increased aggressiveness of tumors not susceptible to chemoprevention by the agents used in this study.

SummaryEarly full-term pregnancy is one of the most effective natural protections against breast cancer. To investigate this effect, we have characterized the global gene expression and epigenetic profiles of multiple cell types from normal breast tissue of nulliparous and parous women and carriers of BRCA1 or BRCA2 mutations. We found significant differences in CD44+ progenitor cells, where the levels of many stem cell-related genes and pathways, including the cell-cycle regulator p27, are lower in parous women without BRCA1/BRCA2 mutations. We also noted a significant reduction in the frequency of CD44+p27+ cells in parous women and showed, using explant cultures, that parity-related signaling pathways play a role in regulating the number of p27+ cells and their proliferation. Our results suggest that pathways controlling p27+ mammary epithelial cells and the numbers of these cells relate to breast cancer risk and can be explored for cancer risk assessment and prevention.

BRCA1-associated breast tumors display loss of BRCA1 and frequent somatic mutations of PTEN and TP53. Here we describe the analysis of BRCA1, PTEN, and p53 at the single cell level in 55 BRCA1-associated breast tumors and computational methods to predict the relative temporal order of somatic events, on the basis of the frequency of cells with single or combined alterations. Although there is no obligatory order of events, we found that loss of PTEN is the most common first event and is associated with basal-like subtype, whereas in the majority of luminal tumors, mutation of TP53 occurs first and mutant PIK3CA is rarely detected. We also observed intratumor heterogeneity for the loss of wild-type BRCA1 and increased cell proliferation and centrosome amplification in the normal breast epithelium of BRCA1 mutation carriers. Our results have important implications for the design of chemopreventive and therapeutic interventions in this high-risk patient population. Significance: Defining the temporal order of tumor-driving somatic events is critical for early detection, risk stratification, and the design of chemopreventive therapies. Our combined experimental and computational approach reveal that the loss of wild-type BRCA1 may not be the first event in the majority of BRCA1-associated breast tumors and may not be present in all cancer cells within tumors. Cancer Discov; 2(6); 503–11. ©2012 AACR. This article is highlighted in the In This Issue feature, p. 473

Although intratumoral chemotherapy administration has been evaluated in the past, its results have not been frequently comparable to those from systemic administration. We recently described microdialysis as a method for local chemotherapy administration with increasing effectiveness while reducing systemic toxicity. We present a mathematical model which supports the successful application of this procedure in optimizing the administered drug in different cases, using informatics tools and considering several parameters. We also review and discuss important aspects of cancer biology that should be taken into consideration in cancer chemotherapy, such as tumor heterogeneity, drug resistance and metastasis, and how this technique may be used to overcome any set-backs presented by these.

Stem cells may have an important etiological role in cancer. Their classic regulatory pathways are deregulated in tumors, strengthening the stem cell theory of cancer. In this manuscript, we review Wnt, Notch and Hedhehog pathways, describing which of their factors may be responsible for the neoplastic development. Furthermore, we classify these elements as oncogenes or tumor suppressor genes, demonstrating their mutation implications in cancer. The activation of these pathways is associated with the expression of certain genes which maintain proliferation and apoptosis inhibition. Further work should be carried out in the future in order to control tumor development by controlling these signaling cascades.

Early full-term pregnancy is the only recognized factor able to prevent breast cancer. There are several hypotheses to explain the mechanisms of this protection, namely an altered hormonal milieu, a differentiation process or a switch in stem cell properties. To explore them, authors have been using animal models, mainly in rodents. Hormonal administration with estrogen and progesterone was the most widely used process to mimic the mammary changes during pregnancy. We have recently proposed that this enigmatic protective role of a full-term birth in breast cancer is carried out by tumor inhibition mediated by differentiated mammary epithelial cells. This explanation may give a new perspective of breast cancer prevention and treatment.