Breast cancer is one of the most widespread forms of solid tumors. By analyzing the traits of breast cancer pathogenesis at the molecular level using modern genetic analysis techniques and at different stages of the disease new data can be obtained to be further utilized in clinical practice. Molecular profiling based on next-generation sequencing is being increasingly applied as a clinical test to select target drugs for treating breast cancer patients with tumors highly resistant to therapy. In this study, we performed targeted sequencing of BRCA1 and BRCA2 oncogenes. In the total of 66 DNA samples from patients with breast tumors, BRCA1/2 mutations were found in 39 patients. There were 78 unique genetic variants, including 30 mutations in BRCA1 and 48 mutations in BRCA2. We identified 33 mutations affecting the sites of post-translational modification in proteins (PMT mutations).