Association between the XRCC3 Thr241Met Polymorphism and Risk of Colorectal Cancer: a Meta Analysis of 5,193 Cases and 6,645 Controls

Background: Many studies have reported associations of the X-ray repair cross-complementing group 3 (XRCC3) Thr241Met polymorphism with colorectal cancer (CRC) risk, but the results remained controversial. Hence, we performed the present meta-analysis with different inheritance models. Materials and Methods: We searched the PubMed and Google scholar databases for studies relating to associations between XRCC3 Thr241Met polymorphism and risk of CRC. 16 studies with 5,193 cases and 6,645 controls were finally included into the meta-analysis. Results: We found that the XRCC3 Thr241Met polymorphism was associated with increased CRC risk only under a dominant genetic model (CC+CT vs. TT: OR 0.575, 95%CI 0.498-1.665, p<0.001, $P_{heterogeneity}=0.00$, $I^2=83%$). There was a significant association between XRCC3 Thr241Met polymorphism and CRC risk in Caucasian in the overall 8 studies under only in the heterozygote genetic model (CT vs. TT: OR=0.929, 95%CI =0.806-1.070, P=0.308, $P_{heterogeneity}=0.002$, $I^2=57%$). Four studies evaluated the XRCC3 Thr241Met polymorphism and CRC risk in Asians. Two genetic models of the XRCC3 polymorphism were significantly correlated with increasing risk in Asians (dominant model: CC+CT vs. TT: OR= 0.609, 95%CI=411-0.902, P=0.013, $P_{heterogeneity}=0.54$, $I^2=0.00%$; Allele model: C vs. T: OR=0.708, 95 %=CI 0.605-0.829, p=0.000, $P_{heterogeneity}=0.000$, $I^2=92%$). The sensitivity analysis suggested stability of this meta-analysis and no publication bias was detected. Conclusions: In conclusion, this meta-analysis indicates that XRCC3 Thr241Met shows an increased CRC risk, particularly in Asians rather than Caucasians.