DETERMINATION OF THE FREQUENCY OF POLYMORPHISM (RS1799796) IN THE XRCC3 GENE IN BREAST CANCER PATIENTS AND HEALTHY INDIVIDUALS, AND COMPARING THEM WITH EACH OTHER IN A POPULATION OF IRANIAN WOMEN

Breast cancer is the most prevalent type of cancer in women worldwide. Biological research indicates that damages caused by genetic and environmental factors to the DNA structure are linked to an increased risk of developing breast cancer. Single nucleotide polymorphisms in DNA repair genes can be associated with differences in the repair efficiency of DNA damage and may affect breast cancer. The XRCC3 protein participates in DNA double-strand breaks and recombination repair, in other words, the product of the XRCC3 gene, plays a key role in homologous recombination repair of DNA double-strand breaks. The polymorphism of AluI plays critical roles in breast cancer development. The aim of the present study was to evaluate associations between the risk of breast cancer and AluI polymorphism in the XRCC3 gene.

In the present case-control study, the polymorphism (rs1799796) of the XRCC3 gene and the risk of breast cancer were evaluated in a population consisting of 100 patients and 100 healthy women residing in the Central Province. The genotypes of the samples were determined using the PCR-RFLP technique. Ultimately, SPSS software version 20 was used for statistical analysis, and the final results were utilized. A significance level of less than P < 0.05 was considered statistically significant.

The average age (age range) in the patient group and the healthy individuals was respectively 52.27 ± 12 (27-90) and 48.08 ± 10 (28-75). Comparison of the age categories between the two groups did not show any significant difference (P = 0.429, χ2 = 0.625). The frequency of allele A was 63.5% in the control group and 70% in the patient group, and the frequency of allele G was 36.5% in the control group and 30% in the patient group. Statistical analyses did not show a significant association between allele frequencies and the risk of breast cancer (P = 0.168). The genotypes had the following frequencies in the two groups: genotype AA was observed in 38% of the control group and 48% of the patient group, genotype AG was 50% and 44% respectively, and genotype GG was 12% in the control group and 8% in the patient group. No significant differences were observed between the patient and control groups for the three genotypes at the rs1799796 locus (P > 0.05).

No significant association was found between polymorphism (rs1799796) in the XRCC3 gene and the risk of breast cancer. Consequently, it is suggested that the rs1799796 polymorphism of the XRCC3 gene cannot be used as a biological marker in predictive clinical studies related to breast cancer risk. Further studies in different populations with a larger statistical sample are required.