Prevalence of BRCA2 mutations and other clinical characteristics in women with triple-negative breast cancer.

Abstract

160 Background: Triple-negative breast cancers (TNBC) represent 10%–20% of invasive breast cancers. Current guidelines recommend genetic testing for women who are diagnosed with TNBC. Studies have shown that BRCA1 mutations are associated with TNBC, but there is little information on the relationship of BRCA2 mutations and TNBC. The purpose of this study was to look at the clinical characteristics of TNBC compared to non-TNBC in a cohort of women with newly diagnosed breast cancer. Methods: The Breast Cancer Database at our institution was queried for patients with invasive breast cancer. We included the following variables: age, race, BRCA1,2, tumor characteristics, and personal history of breast cancer (PHBC). Statistical analyses included Pearson’s Chi-Square and Fisher’s Exact Tests. Results: Out of a total of 1,332 women, 125 (9%) had TNBC. The median age for both TNBC and non-TNBC was 59 years. Majority of women had early stage breast cancer (92%) with ductal carcinoma (80%). There was a significantly higher proportion of Blacks and Asians with TNBC (p < 0.0001). Women with TNBC had higher Ki-67 (p < 0.0001). Within the TNBC group, there were 12 (29%) patients who tested positive for BRCA1,2 mutation and 23 (8%) who tested positive for BRCA 1,2 mutations in the non-TNBC group. Interestingly, BRCA1 was not associated with TNBC (p = 0.40) and BRCA2 was significantly associated with TNBC (p < 0.0001). We also found a higher proportion of TNBC in women who had a PHBC (p = 0.01). Conclusions: In our study, women with TNBC were similar in age to women who did not have TNBC. We found that the women with TNBC in our cohort had elevated rates of BRCA2 mutations. We also found that women with a personal history of breast cancer were at risk for developing TNBC. This may be related to the use of hormonal therapy that reduces the risk of ER/PR-positive tumors. Women of all ages are at risk for developing TNBC and older age at TNBC should not deter from genetic testing.