Risk of having BRCA mutations in women with triple-negative breast cancer: A systematic review and meta-analysis.

Abstract

160 Background: Increased prevalence of BRCA1 mutations (BRCA1) has been associated with the occurrence of triple-negative breast cancer (TNBC) (estrogen receptor [ER]- and progesterone receptor [PR]-negative, HER2-negative) in independent clinical studies. However, BRCA2 mutation (BRCA2) has not been found to overrepresent in women with TNBC. We have performed a meta-analysis of these studies to provide further statistical evidence of the association between BRCA positivity and TNBC. Methods: A Medline search of the MeSH terms “BRCA”, “triple”, and “negative” yielded 37 articles. A search of ASCO abstracts yielded 18 relevant articles. Random effects model was used for analysis due to heterogeneity among the proportions of included studies (Cochran’s Q = 18.52 and 15.18, tau2 = 0.61 and 1.29, I2 = 73% and 80% for BRCA1 and BRCA2 respectively). Mantel-Haenszel method was applied to calculate the pooled event-based odds ratio (OR) with 95% confidence interval (CI). Results: 6 studies including 1,602 BC patients were eligible for analysis of BRCA1 and 4 studies including 1297 BC patients for BRCA2. 172 patients with BRCA1 mutations and 79 patients with BRCA2 mutations were analyzed. Among these 6 studies, 1 included Ashkenazi Jewish women exclusively and 1 included only women of Chinese descent. The overall prevalence of BRCA1 was 10.05% (172 out of 1,602), and for TNBC patients 21.94% (95 out of 433) with an odds ratio of 5.90 (CI: 2.75, 12.66, p < 0.00001). TNBC was not a risk for BRCA2 (OR = 0.67, CI: 0.19, 2.39, p = 0.53). Chinese women with TNBC did not have an elevated risk of BRCA1 (OR = 0.94, CI: 0.24, 3.66) in contrast to Jewish women with TNBC who had the highest risk of BRCA1 among the populations studied (OR = 21.79, CI: 9.03, 52.55). Conclusions: Women with TNBC carry a significantly high risk of having BRCA1 but not BRCA2 mutations. We recommend genetic testing for BRCA1 mutations in women with TNBC especially in Ashkenazi Jewish population. Further studies on Chinese population are needed to further establish the relationship between TNBC and BRCA1 mutations in this cohort.