Clinical and pathologic characteristics of breast cancer patients carrying the c.3481_3491del11 mutation

Tumor characteristics are used today to evaluate the possibility of mutation and to target mutation screening in families with high risk of breast and/or ovarian cancer. We studied the breast tumor profile associated to the c.3481_3491del11 French founder effect mutation on the BRCA1 gene to an attempt to identify any particularity or difference when comparing it to that related to other BRCA1 mutations. Within the population who were referred to our oncogenetic clinic at the Lorraine Oncology Institute in France and who underwent genetic testing between 1994 and 2012, we identified 404 women carrying a BRCA1 mutation. Interestingly, 45% (180/404) women had the germline c.3481_3491del11 mutation. These included 91 patients affected by first breast cancer. Clinical and pathologic data were retrieved from medical files. Descriptive statistics were conducted using the SPSS software (version 20.0). For the entire cohort of 91 women, the mean age was 43.64 years (SD 10.04). Tumors were identified in 37.4% of cases aged < 40 years. Estrogen receptor status and progesterone receptor status were reported to 67 patients. Seventy-four percent were ER negative. Hormonal receptors status was negative in 68.6% of tumors. HER2 status was available for 32 tumors. The triple-negative subtype was found in 21 cases, which accounts for 65.6% of the patients. High tumor grade was found in 81% of triple negative breast cancer patients. Based on our results compared to those of previous international studies, we concluded that the breast cancer associated to the c.3481_3491del11 is not different from that associated to other BRCA1 mutations. A larger cohort with complete information on the breast cancer pathologic characteristics and including other BRCA1 mutations would allow us to statistically compare the breast tumor profile associated to the c.3481_3491del11 to that related to other BRCA1 mutations.