Risk of having BRCA1 mutation in high-risk women with triple-negative breast cancer: a meta-analysis.

Testing for BRCA1 mutation has important clinical implications such as identifying risk of second primary cancers and risk of cancer in the family. This study seeks to quantify the risk of having BRCA1 mutation in female breast cancer patients with triple-negative phenotype compared with those with other phenotypes. We undertook a search of MEDLINE and EMBASE databases for relevant studies through 10 May 2013. Outcomes were calculated and reported as risk ratio and risk difference. 12 studies comprising 2533 breast cancer patients were included in the analysis. It was found that almost all eligible studies were performed on high-risk population with breast cancer. By analyzing the incidence rates of BRCA1 mutation in patients with triple-negative breast cancer (TNBC) and non-TNBC, our meta-analysis provides a relative risk of 5.65 [95% confidence interval (CI), 4.15-7.69] and risk difference of 0.22 (95% CI, 0.15-0.29). This implies that, in selected population with high-risk features, women with TNBC are approximately five and a half times more likely to have BRCA1 mutation compared with non-TNBC phenotype, and approximately two in nine women with TNBC harbor BRCA1 mutation. Triple-negative phenotype significantly increases the risk of having BRCA1 mutation in high-risk breast cancer patients compared with non-TNBC.