Polymorphisms of DNA repair genes, XRCC1 and XRCC3, and susceptibility to familial prostate cancer in a Japanese population

Aim: DNA repair systems play an important role in protecting the genome damaged by endogeneous and exogeneous mutagens. Deficiency in these systems has been reported to increase the risk of various types of cancer. We investigated two DNA repair genes, X‐ray repair cross‐complementing group 1 (XRCC1) and X‐ray repair cross‐complementing group 3 (XRCC3), to assess the association between DNA repair genes and familial prostate cancer susceptibility in the Japanese population. Methods: We performed a case‐control study consisting of 142 familial prostate cancer cases and 119 normal control subjects. The genetic polymorphism was analyzed by the polymerase chain reaction‐restriction fragment length polymorphism method. Results: Of the three polymorphisms investigated, the frequency of the XRCC1 codon 194 Arg/Trp genotype, was significantly observed in cases (odds ratio [OR] = 2.19, 95% confidence interval [CI] = 1.28–3.73, P = 0.0058) and the Arg/Trp and Trp/Trp genotypes were also significantly observed in cases (OR = 2.03, 95% CI = 1.23–3.36, P = 0.0080). For the Arg399Gln genotype in XRCC1 and the Thr241Met genotype in XRCC3, no significant differences were observed between cases and controls. Stratification of cases according to clinical stages and pathological grades showed no significant difference among clinical parameters and genotypes. Conclusion: The Trp allele in the XRCC1 codon 194 was significantly associated with individuals in the Japanese population with a family history of prostate cancer.