Assessment of the Frequency of BRCA1/2 Mutations Detection by Means of PCR in State Budgetary Healthcare Institution «Saint-Petersburg Clinical Scientific and Practical Center for Specialised Types of Medical Care (oncological) Named after N.P. Napalkov»

Background.BRCA1/2 germline testing allows us to optimize treatment strategy for patients with breast and ovarian cancer cases,to provide early diagnosis and also prophylactic measures for mutation carriers. Considering absence of large BRCA studies on Russian population, we do not have any clear understanding of approximate BRCA1/2 germline mutation frequency, a whole number of founder mutations and impact of non-founder BRCA1/2 mutations, which are not included in a standard PCR panel. Objective. Assessment of the frequency of BRCA1/2 mutations detection by means of PCR in breast and ovarian cancer patients in real clinical practice in St. Petersburg Clinical Scientific and Practical Center for Specialized Types of Medical Care (oncological) named after N.P. Napalkov. Analysis of a database for BRCA1/2-negative patients on a presence of risk factors associated with a probability of carrying a germline mutation in BRCA1/2 genes. Materials and methods. We retrospectively evaluated 335 ovarian and 1196 breast cancer patients, tested for germline BRCA1/2 by PCR in SPb CSPC(o) named after N.P. Napalkov from 01.01.2019 to 31.12.2021. For analysis was used patient’s blood plasma and a standard PCR panel detecting 8 mutation variants. A database for BRCA1/2-negative patients was retrospectively analyzed on a presence of risk factors associated with a high probability of hereditary cancer: an early onset and family history of cancer (BRCA associated). Statistical analysis was carried out using the SPSS software package (IBM® SPPS® Statistics v. 20), a number of graphs were carried out using Microsoft® Excel® 2016 programs. Results. BRCA1/2 germline mutations were detected in 6,4% (n= 98). Mean frequency of detection was 12,6% (n=45) for ovarian cancer patients, 4,3% (n=53) for breast cancer patients. Analysis of a database for BRCA1/2-negative patients demonstrated that 22,5% (n=346) BC and OC cases had an early onset. Family history of cancer was identified for 13,6% (n=195) patients with breast or ovarian cancer, including 3,8% (n=43) with 2 and more family cases of BRCA associated cancers. Conclusions. The frequency of detected BRCA1/2 germline mutations by PCR for breast and ovarian cancer patients in SPb CSPC(o) named after N.P. Napalkov is lower than the one described in international data. A large part of patients BRCA1/2 negative by PCR test has characteristics of hereditary breast cancer syndrome and requires further NGS.