BRCA1 is a key regulator of breast differentiation through activation of Notch signalling with implications for anti-endocrine treatment of breast cancers

Here, we show for the first time, that the familial breast/ovarian cancer susceptibility gene BRCA1 activates the Notch pathway in breast cells by transcriptional upregulation of Notch ligands and receptors in both normal and cancer cells. We demonstrate through chromatin immunoprecipitation assays that BRCA1 is localized to a conserved intronic enhancer region within the Notch ligand Jagged-1 (JAG1) gene, an event requiring ΔNp63. We propose that this BRCA1/ΔNp63-mediated induction of JAG1 may be important the regulation of breast stem/precursor cells, as knockdown of all three proteins resulted in increased tumoursphere growth and increased activity of stem cell markers such as Aldehyde Dehydrogenase 1 (ALDH1). Knockdown of Notch1 and JAG1 phenocopied BRCA1 knockdown resulting in the loss of Estrogen Receptor-α (ER-α) expression and other luminal markers. A Notch mimetic peptide could activate an ER-α promoter reporter in a BRCA1-dependent manner, whereas Notch inhibition using a γ-secretase inhibitor reversed this process. We demonstrate that inhibition of Notch signalling resulted in decreased sensitivity to the anti-estrogen drug Tamoxifen but increased expression of markers associated with basal-like breast cancer. Together, these findings suggest that BRCA1 transcriptional upregulation of Notch signalling is a key event in the normal differentiation process in breast tissue.

Screening-detected non-symptomatic breast cancer: a case history

Alice is a 65 year-old woman who was recalled for further investigations following a routine screening mammogram, which showed a 25 mm mass in her left breast. This case history will report on the further investigations and surgery required to manage this infiltrating ductal carcinoma. The histopathology report will be analysed to provide a rationale for future treatment with radiotherapy, and Alice's expected prognosis will be presented using the Nottingham Prognostic Index. Alice's psychological support needs will identified and the appropriate interventions will be discussed with a particular focus on Alice's history of depression. The supportive and educational role of the breast care nurse and the multidisciplinary team will be highlighted throughout the study.

Breast cancer survival and stage at diagnosis in Australia, Canada, Denmark, Norway, Sweden and the UK, 2000-2007:A population-based study

Background: We investigate whether differences in breast cancer survival in six high-income countries can be explained by differences in stage at diagnosis using routine data from population-based cancer registries. Methods: We analysed the data on 257 362 women diagnosed with breast cancer during 2000-7 and registered in 13 population-based cancer registries in Australia, Canada, Denmark, Norway, Sweden and the UK. Flexible parametric hazard models were used to estimate net survival and the excess hazard of dying from breast cancer up to 3 years after diagnosis.Results:Age-standardised 3-year net survival was 87-89% in the UK and Denmark, and 91-94% in the other four countries. Stage at diagnosis was relatively advanced in Denmark: only 30% of women had Tumour, Nodes, Metastasis (TNM) stage I disease, compared with 42-45% elsewhere. Women in the UK had low survival for TNM stage III-IV disease compared with other countries. Conclusion: International differences in breast cancer survival are partly explained by differences in stage at diagnosis, and partly by differences in stage-specific survival. Low overall survival arises if the stage distribution is adverse (e.g. Denmark) but stage-specific survival is normal; or if the stage distribution is typical but stage-specific survival is low (e.g. UK). International differences in staging diagnostics and stage-specific cancer therapies should be investigated. © 2013 Cancer Research UK. All rights reserved.

Predictions of survival up to 10 years after diagnosis for European women with breast cancer in 2000-2002

Few studies have addressed longer-term survival for breast cancer in European women. We have made predictions of 10-year survival for European women diagnosed with breast cancer in 2000-2002. Data for 114,312 adult women (15-99 years) diagnosed with a first primary malignant cancer of the breast during 2000-2002 were collected in the EUROCARE-4 study from 24 population-based cancer registries in 14 European countries. We estimated relative survival at 1, 5, and 10 years after diagnosis for women who were alive at some point during 2000-2002, using the period approach. We also estimated 10-year survival conditional on survival to 1 and 5 years after diagnosis. Ten-year survival exceeded 70% in most regions, but was only 54% in Eastern Europe, with the highest value in Northern Europe (about 75%). Ten-year survival conditional on survival for 1 year was 2-6% higher than 10-year survival in all European regions, and geographic differences were smaller. Ten-year survival for women who survived at least 5 years was 88% overall, with the lowest figure in Eastern Europe (79%) and the highest in the UK (91%). Women aged 50-69 years had higher overall survival than older and younger women (79%). Six cancer registries had adequate information on stage at diagnosis; in these jurisdictions, 10-year survival was 89% for local, 62% for regional and 10% for metastatic disease. Data on stage are not collected routinely or consistently, yet these data are essential for meaningful comparison of population-based survival, which provides vital information for improving breast cancer control. What's new? Policy-makers and health-care planners need accurate data on long-term survival to improve cancer control. This Europe-wide study of 10-year survival identified low survival in Eastern Europe for women with breast cancer in 2000-2002, and wide variation by age at diagnosis. Data on stage at diagnosis are crucial for meaningful comparison of population-based survival, and fundamental for improving breast cancer control, but our analyses confirmed that stage data are not collected routinely or consistently Copyright © 2012 UICC.

Model selection for prognostic time-to-event gene signature discovery with applications in early breast cancer data

Model selection between competing models is a key consideration in the discovery of prognostic multigene signatures. The use of appropriate statistical performance measures as well as verification of biological significance of the signatures is imperative to maximise the chance of external validation of the generated signatures. Current approaches in time-to-event studies often use only a single measure of performance in model selection, such as logrank test p-values, or dichotomise the follow-up times at some phase of the study to facilitate signature discovery. In this study we improve the prognostic signature discovery process through the application of the multivariate partial Cox model combined with the concordance index, hazard ratio of predictions, independence from available clinical covariates and biological enrichment as measures of signature performance. The proposed framework was applied to discover prognostic multigene signatures from early breast cancer data. The partial Cox model combined with the multiple performance measures were used in both guiding the selection of the optimal panel of prognostic genes and prediction of risk within cross validation without dichotomising the follow-up times at any stage. The signatures were successfully externally cross validated in independent breast cancer datasets, yielding a hazard ratio of 2.55 [1.44, 4.51] for the top ranking signature.