Association of XRCC1 polymorphisms with thyroid cancer risk.

Due to the important role in the DNA repair pathways, numerous studies have been carried out to explore the relationship between the polymorphisms in the X-ray repair cross-complementing group 1 (XRCC1) gene and thyroid cancer risk. But previous reports have produced conflicting results. Thus, we performed an updated comprehensive meta-analysis to better investigate the association of the XRCC1 polymorphisms with thyroid cancer risk. There were a total of nine studies included with 1,621 cases and 3,669 controls examining the effects of the XRCC1 Arg280His, Arg399Gln, and Arg194Trp polymorphisms on the susceptibility of thyroid cancer. In our study, the XRCC1 Arg280His polymorphism was found to be associated with an increased thyroid cancer risk in the Caucasian population [allelic contrast: odds ratio (OR) = 1.38, 95% CI = 1.05-1.80, P(Z) = 0.02, P(Q) = 0.61; dominant model: OR = 1.43, 95% CI = 1.08-1.89, P(Z) = 0.01, P(Q) = 0.57]. The Arg399Gln polymorphism was associated with a significant decreased risk [allelic contrast: OR = 0.73, 95% CI = 0.59-0.92, P(Z) = 0.006, P(Q) = 0.31; dominant model: OR = 0.73, 95% CI = 0.55-0.97, P(Z) = 0.03, P(Q) = 0.33; recessive model: OR = 0.56, 95% CI = 0.34-0.93, P(Z) = 0.02, P(Q) = 0.59], while the Arg194Trp SNP conferred an increased risk for thyroid cancer in the mixed populations [allelic contrast: OR = 1.49, 95% CI = 1.02-2.17, P(Z) = 0.04]. To conclude, the present meta-analysis demonstrated that the polymorphisms in the XRCC1 gene may be associated with developing of thyroid cancer.