BRCA1- and BRCA2-related metastatic breast cancers, with at least 1 prior chemotherapy regimen, treated by high-dose (n = 27) or low-dose (n = 27) olaparib. OR in 41% and 22%; SD in 44% and 44%; median PFS = 5.7 and 3.8 months. This evidence concerns the gene BRCA2 and breast cancer.