According to high-risk groups in this study, mutation of BRCA1/2 genes were identified in 8.5% among early onset patients, in 17.7% among bilateral breast cancer, in 50.0% among patients with both breast and ovarian cancer, in 5.9% among male breast cancer patients, in 7.6% among patients with cancer of multiple organs, and in 27.1% among patients having two or more of these high-risk factors. The gene discussed is BRCA1; the disease is breast cancer.