Approximately 3-5% of breast cancer patients are BRCA1- or BRCA2 germ-line mutation carriers. In this study we correlated the distribution of intrinsic molecular subtypes according to failure pattern in a Danish cohort of BRCA germ-line mutated breast cancer patients. Tumor tissue from 425 BRCA germ-line mutated breast cancer patients were analyzed by immunohistochemistry (IHC) for hormone receptor status, proliferation index (Ki67) and HER2. Surrogate intrinsic molecular subtypes were assigned according to approximated St. Gallen criteria. Annual hazard rates (AHR) were calculated for death and local- or distant relapse, contralateral breast cancer, new primary cancer other than breast cancer, or death as first event (disease-free event). Luminal A-like subtype was observed with a frequency of 9% and 35% for BRCA1 and BRCA2, respectively and, for both BRCA1 and BRCA2 patients, the luminal B-like subtype was more frequent than the luminal A-like subtype (BRCA1 21% and BRCA2 40% luminal B-like). No events or deaths were observed for luminal A-like subtype during the first 2.5years and 0-5years, respectively. AHR for luminal B-like tumors was 5.34% (95% CI=1.49-1.19) and 1.76% (95% CI=0.36-3.16) for disease-free event and death, respectively, and for basal-like 6.58% (95% CI=2.98-10.18) and 4.54% (95% CI=2.69-6.40). A substantial proportion of BRCA carriers had luminal A-like subtype, and these were mainly BRCA2 carriers. Luminal A-like subtype was significantly associated with low AHR the first five years after surgery. This study warrants further exploration of the impact of the molecular intrinsic subtypes on survival in BRCA-mutated breast cancer patients.
|Status||Udgivet - feb. 2019|