A Systematic Review of the Prevalence of Germline BRCA mutations in North Asia Breast Cancer Patients

The BRCA1/2 mutation status testing is the global standard of care for breast cancer patients with a family history of cancer. BRCA1/2 mutations are known to be ethno-specific. For some ethnic groups of the Northern Asia (Buryats, Yakuts, Altaians, Tuvans, Khakasses, etc.) the founder mutations in the BRCA1/2 genes have not been revealed. This systematic review was conducted to assess the prevalence of BRCA1/2 mutation in breast cancer patients inhabiting Eastern Europe and Northern Asia (or Siberia). A total of 23,561 studies published between 2014 and 2024 were analyzed, of which 55 were included in the review. The literature search was conducted using RusMed, Cyberleninka, Google Scholar, eLibrary, NCBI databases (n=5) and conference papers. The founder mutations (c.5266dupC and/or c.181T>G) of BRCA1 gene that were frequently observed in the Slav peoples were also identified in Chechens, Armenians, Bashkirs, Ukrainians, Mordovians, Mari, Kabardians, Tatars, Uzbeks, Kyrgyz, Ossetians, Khanty indigenous peoples and Adygs. For Chechens, Kabardians, Ingush, Buryats, Khakasses, Sakha, Tuvans and Armenians, rare pathogenic variants of the BRCA1/2, ATM, СНЕК2, BRIP1, NBN, PTEN, TP53, PMS1, XPA, LGR4, BRWD1 and PALB2 genes were found. No data are available about the frequency of pathogenic BRCA1/2 mutations for ethnic groups, such as the Udmurts, Komi, Tajiks, Tabasarans, and Nogais indigenous people. This is the first systematic review that provides the spectrum of BRCA mutations in ethnic groups of breast cancer patients inhabiting Eastern Europe and Northern Asia. It has been shown that the mutations are ethnospecific (varied widely within groups) and not all groups are equally well studied. Further studies on the ethnic specificity of BRCA gene mutations are required.