Project description:gBRCA1/2 mutations increase the incidence of breast cancer (BC) by interrupting the homologous recombination repair (HRR) pathway. Although gBRCA1 and gBRCA2 BC have similar clinical profiles, different molecular characteristics have been observed. In this study, we conducted comprehensive genomic analyses and compared gBRCA1/2 BC. Sanger sequencing to identify gBRCA1/2 mutations was conducted in 2,720 patients, and gBRCA1 (n=128) and gBRCA2 (n=126) mutations were analyzed. Within that population, deep target sequencing (TS) and matched whole transcriptome sequencing (WTS) results were available for 46 and 34 patients, respectively. An internal database of breast-cancer patients with wildtype gBRCA was used to compile a TS (n=195) and WTS (n=137) reference dataset. Three specific mutation sites, p.Y130X (n=14) and p.1210Afs (n=13) in gBRCA1 and p.R294X (n=22) in gBRCA2, were comparably frequent. Immunohistochemistry subtyping determined that the incidence of triple negative BC was higher among those with a gBRCA1 mutation (71.9%), and estrogen receptor (ER)-positive BC was dominant in those with a gBRCA2 mutation (76.2%). gBRCA1/2 mutations were mutually exclusive with PIK3CA somatic mutations (P<0.05), and gBRCA1 frequently co-occurred with TP53 somatic mutations (P<0.05). The median tumor mutation burden was 6.53 per megabase (MB) in gBRCA1 and 6.44 per MB in gBRCA2. The expression of AR, ESR1, and PGR was significantly upregulated with gBRCA2 mutation compared with gBRCA1 mutation. gBRCA1 and gBRCA2 BC have similar clinical characteristics, but they have different molecular subtypes, co-altered somatic mutations, and gene expression patterns. Implications: Even though gBRCA1 and gBRCA2 mutations both alter HRR pathways, our results suggest that they generate different molecular characteristics and different mechanisms of carcinogenesis.
Project description:BackgroundBreast cancer is the most common cancer diagnosed among Latinas in the United States and the leading cause of cancer-related death among this population. Latinas tend to be diagnosed at a later stage and have worse prognostic features than their non-Hispanic white counterparts. Genetic and genomic factors may contribute to observed breast cancer health disparities in Latinas.MethodsWe provide a landscape of our current understanding and the existing gaps that need to be filled across the cancer prevention and control continuum.ResultsWe summarize available data on mutations in high and moderate penetrance genes for inherited risk of breast cancer and the associated literature on disparities in awareness of and uptake of genetic counseling and testing in Latina populations. We also discuss common genetic polymorphisms and risk of breast cancer in Latinas. In the treatment setting, we examine tumor genomics and pharmacogenomics in Latina patients with breast cancer.ConclusionsAs the US population continues to diversify, extending genetic and genomic research into this underserved and understudied population is critical. By understanding the risk of breast cancer among ethnically diverse populations, we will be better positioned to make treatment advancements for earlier stages of cancer, identify more effective and ideally less toxic treatment regimens, and increase rates of survival.
Project description:Background:This study was a hypothesis generating exploration of genomic data collected at diagnosis for 19 patients, who later participated in a clinical trial. BRCA1/2 germline mutation related hereditary cancers are candidates for new immune therapeutic interventions. However, contrary to what is expected of tumors with compromised DNA repair, a prominent tumor mutation burden (TMB) in hereditary breast and ovarian cancers in this cohort, was not correlated with high global immune activity in their microenvironments. More information is needed about the relationship between genomic instability, phenotypes and immune microenvironments of BRCA1/2 related hereditary tumors in order to find appropriate markers of immune activity and the most effective anticancer immune strategies. Methods:Mining and statistical analyses of the original DNA and RNA sequencing data and data available from The Cancer Genome Atlas (TCGA) were performed using the R computing environment. To interpret the data, we have used published literature and web available resources such as Gene Ontology Tools, The Cancer immunome Atlas (TCIA) and the Cancer Research Institute iAtlas. Results: We found that BRCA1/2 germline related breast and ovarian cancers do not represent a unique phenotypic identity, but that they express a range of phenotypes similar to sporadic cancers. Importantly, BRCA2 germline mutation related breast tumors have a different profile of genomic instability compared to those related to BRCA1. However, all breast and ovarian BRCA1/2 related tumors are characterized by high homologous recombination deficiency (HRD) and low aneuploidy. Interestingly, all sporadic high grade serous ovarian cancers (HGSOC) and most of the subtypes of triple negative breast cancers (TNBC), but not other types of breast cancer, also express a high degree of HRD. Conclusion: : Tumor mutation burdon (TMB) is not associated with the magnitude of the immune response in hereditary BRCA1/2 related breast and ovarian cancers or in sporadic TNBC and sporadic HGSOC. Hereditary tumors express phenotypes as heterogenous as sporadic tumors with various degree of “BRCAness” and various characteristics of the immune microenvironments. The subtyping criteria developed for sporadic tumors can be applied for the classification of hereditary tumors and possibly also characterization of their immune microenvironment. A high HRD score may be a good candidate biomarker for response to platinum, and potentially PARP-inhibition.