Association between polymorphisms in the DNA repair genes XRCC1 and APE1, and the risk of prostate cancer in white and black Americans

Purpose: XRCC1 and APEI are enzymes involved in the repair of DNA strand breaks and base damage that arise from various endogenous and exogenous oxidants. We determined whether polymorphisms in XRCC1 and APE1 increase the risk of prostate cancer. Materials and Methods: We performed a case-control study in 228 white American men, 124 black American men, and 335 age, sex and race matched controls. Polymorphisms at codon 399 in XRCC1, and at codons 51 and 148 in APE1 were determined using an restriction fragment length polymorphism method. Frequencies were compared between cases and controls. Results: A significantly increased risk of prostate cancer was observed in white men with the XRCC1(399Gln) allele (OR 1.6, 95% C1 1.1 to 2.4). When APE1 and XRCC1 polymorphisms were evaluated together, we found an increased risk of the XRCC1(399Arg/Gln+Gln/Gln)/ApE1(51Gln/Gln) (OR 4.0, 95% CI 1.3 to 12.5) and XRCC1(399Arg/Gln+Gln/Gln)/ApE1(148Asp)/(Asp) (OR 2.9, 95% CI 1.4 to 6.1) genotypes in white men. Significant associations were found between combined genotypes and prostate cancer risk with a dose-effect relationship in white men (trend test p = 0.035 and 0.039, respectively). No significant associations were observed between polymorphisms in these genes and prostate cancer risk in black men. Conclusions: Our results suggest that inherited variability in DNA repair capacity, as reflected by polymorphisms in XRCC1 and APE1, is a risk factor for prostate cancer.