No evidence of association between the synonymous polymorphisms in XRCC1 and ERCC2 and breast cancer susceptibility among nonsmoking Chinese

DNA repair proficiency has also been proposed as a potential susceptibility factor for breast cancer. Synonymous polymorphism roles of the DNA repair genes in relation to breast cancer remain largely unknown. Nonsmokers are a good model in which to investigate genetic susceptibility to cancer because they are at low-dose carcinogen exposure. To validate genetic biomarkers of the disease, we explored the effects of the two synonymous polymorphisms [Pro206Pro (rs915927) and Arg156Arg (rs238406)] in the DNA repair genes XRCC1 and ERCC2 at chromosome 19q13.2-3 on breast cancer susceptibility among nonsmoking Chinese. The study recruited 243 patients with breast cancer and 234 cancer-free controls matched to the cases by age (± 3 years), gender, nonsmoking status and ethnicity. Genotypes were determined using polymerase chain reaction-restriction fragment length polymorphism. No associations were observed between both individual single nucleotide polymorphisms or haplotypes and breast cancer susceptibility. After stratification, no effects were detected for age-dependent effects or menopause status in relation to breast cancer occurrence. No evidence of gene-gene interaction in breast cancer susceptibility was revealed. The two loci were at weak linkage disequilibrium (D′ value = 0.244, P = 0.07). The present data suggest that XRCC1 Pro206Pro and ERCC2 Arg156Arg do not substantially influence breast cancer susceptibility among nonsmoking Chinese.

► We explored the effects of XRCC1 rs915927 and ERCC2 rs238406 on breast cancer. ► No evidence was observed between both single SNPs or haplotypes and the disease. ► No evidence was found between age-dependent or menopause status and the disease. ► No evidence of gene-gene interaction in breast cancer risk was revealed. ► The two synonymous polymorphisms do not influence breast cancer risk in nonsmokers.