Response to neoadyavant chemotherapy with platinum-based drugs in breast cancer patients with BRCA1 deletion in tumor

Currently, the presence of the germinal mutation BRCA1 5382insC in breast cancer patients is one of the determining factors for prescribing platinum-based drugs. However, this type of mutation is found in no more than 10 % of patients, thus limiting the feasibility of administering platinum-based drugs. Various somatic changes in the BRCA1 gene in breast tumors, in particular the deletions of this gene, can play an important role in the tumor sensitivity to platinum drugs. Case description. We present the case of a 42-year-old woman diagnosed with breast cancer. the deletion of the BRCA1 gene was detected in the tumor. the patient had a complete response to preoperative chemotherapy according to the CP regimen. Conclusion. the frequency of the germline mutation of the BRCA1 gene does not exceed 10 %, and the deletion frequency of this gene can vary from 30 to 45 %, thus greatly increasing the feasibility of using platinum-based drugs in mutationnegative patients to achieve complete pathologic response and high survival rates.