Frequencies of Diagnostically Significant Polymorphisms of Hereditary Breast Cancer Forms in BRCA1 and BRCA2 Genes in the Kazakh Population.

Objective: Breast cancer is the most common form of cancer in women in the world with more than 400,000 deaths each year worldwide. The aim of this study is to compare population frequencies of alleles and genotypes of polymorphic variants of BRCA1 and BRCA2 genes associated with breast cancer risk in an ethnically homogenous Kazakh population with previously studied world populations. The material of the study was DNA isolated from peripheral blood of the enrolled population control group, represented by 1800 conditionally healthy individuals of Kazakh ethnicity.

Methods: The DNA extraction was possible with the use of M-PVA magnetic particle separation method on the Prepito (PerkinElmer) automatic analyser for extraction of Chemagic Prepito (Wallac, Finland) nucleic acids using the PrepitoDNACytoPure reagent kit. Statistical calculations of allele and genotype frequencies, significance tests, and non-parametric χ2 analysis were carried out using PLINK software.

Results: The results favour for the high genetic heterogeneity of the studied polymorphisms, which reflects the specifics of the Kazakh population structure resulted from complex evolutionary and migration processes, as well as the median geographic location between the populations of Asia and Europe.

Conclusion: Knowledge of the spectrum and frequency of mutations in BRCA1 and BRCA2 genes predisposing to breast cancer, which are present in varying frequencies in the Kazakh population, will provide a more effective approach to the screening protocol and allow for a faster, less expensive and more accessible genetic testing strategy for the Kazakhstan citizens.