BRCA1 and breast cancer: However, RRBM-RRBSO or just RRBSO was the most effective risk-reducing strategy in patients with TN breast cancer aged over 40 years with the BRCA1 pathogenic variant in exons 12-24 in stage II and in patients aged over 35 years with the BRCA2 pathogenic variant in exons 12-24 in stage II.