XRCC1 R399Q polymorphism and colorectal cancer risk in the Chinese Han population: a meta-analysis.

X-ray repair cross-complementing group 1 (XRCC1) plays a key role in DNA repair, genetic instability, and tumorigenesis. The XRCC1 R399Q polymorphism has been reported in some studies to influence the risk of colorectal cancer (CRC), though this remains controversial. We performed a meta-analysis to determine the association of XRCC1 R399Q polymorphisms with CRC risk in the Chinese Han population. A literature search was conducted using PubMed, EMBASE, and the China National Knowledge Infrastructure to identify eligible studies published before June 2014. The pooled odds ratio (OR) and corresponding 95% confidence interval (CI) were used to estimate the effect of XRCC1 R399Q polymorphisms on CRC risk. Eleven case-control studies with a total of 3194 CRC cases and 4472 controls were identified. No significant association between the XRCC1 R399Q polymorphism and CRC risk was observed in the Chinese Han population (Gln/Gln vs. Arg/Arg, OR = 1.26, 95% CI = 0.85-1.87, P OR = 0.242; Arg/Gln vs. Arg/Arg, OR = 0.95, 95% CI = 0.70-1.18, P OR = 0.651; dominant model, OR = 1.09, 95% CI = 0.86-1.38, P OR = 0.480; and recessive model, OR = 1.24, 95% CI = 0.91-1.70, P OR = 0.177). After excluding two studies that deviated from the Hardy-Weinberg equilibrium, there remained no significant association between XRCC1 R399Q and CRC risk. No publication bias was found using the funnel plot and Egger's test. Our meta-analysis results suggest that the XRCC1 R399Q polymorphism is not associated with increased risk of CRC in the Chinese Han population.