Variants in BRCA1 exon 14 were detected in 37 breast cancer patients and 16 ovarian cancer patients; this was the most frequently mutated exon of BRCA1. The next most common exon of BRCA1 with variants was exon 17 (27 breast cancer patients and 12 ovarian cancer patients) (Fig. 2A). This evidence concerns the gene BRCA1 and breast cancer.