TP53 GENE POLYMORPHISM AND BREAST CANCER RISK IN RADIATION-EXPOSED KAZAKH WOMEN

Abstract

Background. TP53 rs1042522 (Arg72Pro) is a functionally significant polymorphism that alters the apoptotic activity of the p53 protein and is potentially associated with cancer susceptibility. Its contribution to cancer risk in radiation-exposed populations remains insufficiently explored. This study aimed to analyze the frequency of this polymorphism in women with breast cancer residing near the former Semipalatinsk nuclear test site, considering both hereditary and environmental risk factors. Materials and methods. A case-control study was conducted involving 250 Kazakh women aged 40 to 79 years. Participants were categorized into groups based on cancer diagnosis, family history, and radiation exposure. Genotyping of the TP53 rs1042522 polymorphism was performed using real-time PCR. Statistical analysis included calculation of odds ratios (OR) with 95% confidence intervals (CIs), with Bonferroni correction applied where necessary. Results. The frequency of GC/CC genotypes was significantly higher among breast cancer patients with both a family history and documented radiation exposure (OR = 6.91; 95% CI: 1.89–25.21; p = 0.0020). A meaningful association was also observed in sporadic breast cancer cases – women with no known familial or radiation-related predisposition (OR = 4.30; 95% CI: 1.15–16.09; p = 0.0269). Genotype distribution in the control group was consistent with Hardy-Weinberg equilibrium, supporting the validity of sampling and genotyping procedures. Conclusion. The findings of this study suggest that the TP53 rs1042522 polymorphism may contribute to increased susceptibility to breast cancer in women exposed to ionizing radiation. These results highlight the importance of an integrated approach to cancer risk assessment that includes both genetic and environmental factors, and emphasize the need for further investigation of TP53 as a potential biomarker in vulnerable populations.