Aims: Polymorphisms in DNA damage repair genes may affect DNA repair capacity and modulate breast cancer susceptibility. In this study, we aimed to analyze two polymorphisms for each of the DNA repair genes X-ray repair cross-complementing group 1 (XRCC1) rs25487 and rs1799782 and excision repair cross-complementing group 1 (ERCC1) rs3212964 and rs11615, to evaluate their associations with the risk of sporadic breast cancer in Han women in the Gansu Province of China.
Methods: Genotypes were determined by a polymerase chain reaction-based approach for 101 patients with breast cancer and in 101 disease-free controls.
Results: We found that individuals with the AA genotype at XRCC1 rs25487 had a significantly increased risk of breast cancer compared with GG genotype (p<0.001, odds ratio [OR]=6.39, 95% confidence interval [CI]: 2.18-18.65). The dominant model showed that the combined rs25487 genotypes (AA+AG) increased the disease risk (p<0.001, OR=3.17, 95% CI: 1.76-5.72). However, no statistical associations were found between rs1799782 in XRCC1, or rs3212964 and rs11615 in ERCC1 and the risk of disease. In haplotype analysis, the GC haplotype in XRCC1 conferred an increased risk (p<0.001) with a 4.78-fold increase for each copy (95% CI: 2.52-8.72). Significant associations were also shown between the single nucleotide polymorphisms (SNPs) and the status of estrogen receptor (ER), progesterone receptor (PR), and HER-2.
Conclusions: The results suggest that the XRCC1 rs25487 polymorphism may increase the risk of breast cancer.