Among the group of women with BRCA1 and BRCA2 mutations, there was a statistically nonsignificant decrease in the risk of breast cancer with a hazard ratio of 0.86 (95% CI = 0.45 to 1.67), without any statistically significant differences noted when stratified by BRCA1 vs BRCA2, menopausal status, or a previous history of breast cancer. This evidence concerns the gene BRCA2 and breast cancer.