Association between X-ray repair cross-complementing group 1 gene polymorphisms and glioma risk: a systematic review and meta-analysis based on 22 case-control studies.

OBJECTIVES Glioma is the most common central nervous system tumor. This systematic review and meta-analysis is aimed to systematically assess the association of XRCC1 polymorphisms with the risk of glioma. METHODS Such databases as EMbase, PubMed, The Cochrane Library, the China National Knowledge Infrastructure (CNKI) platforms, VIP and WanFang were searched up to April 2015 to collect case-control studies of association between XRCC1 polymorphisms and glioma. Data were extracted and meta-analysis was conducted by using Stata 12.0 softwares. RESULTS A total of 22 studies were included in the meta-analysis, including 18503 glioma patients and 24367 controls. The overall data indicated that XRCC1 Arg194Trp (C>T) polymorphism significantly increased glioma risk (allele C versus T: OR=0.72, 95% CI=0.55-0.93, CC versus TT: OR=0.55, 95% CI=0.46-0.67; CC versus CT+TT: OR=0.64, 95% CI=0.45-0.91 and CC+CT vs. TT: OR=0.61, 95% CI=0.51-0.74), especially in Asia ethnicity. XRCC1 Arg280His (G>A) polymorphism has no association with glioma (allele G versus A: OR=1.01, 95% CI=0.83-1.22; GG versus AA: OR=1.07, 95% CI=0.66-1.75; GA versus AA: OR=1.01, 95% CI=0.77-1.32; GG versus GA+AA: OR=1.01, 95% CI=0.84-1.22 and GG+GT versus AA: OR=1.06, 95% CI=0.67-1.69). XRCC1 Arg399Gln (G>A) polymorphism will significantly increase glioma risk in Asian (allele G versus A: OR=0.78, 95% CI= 0.72-0.84; GG versus AA: OR=0.56, 95% CI=0.47-0.66; GA versus AA OR=0.71, 95% CI=0.59-0.84; GG versus GA+AA: OR=0.76, 95% CI=0.68-0.84 and GG+GA vs. AA: OR=0.62, 95% CI=0.53-0.73) but not Caucasian ethnicity. XRCC1 Pro161Leu (C>T), Leu387Leu (G>A), Pro602Thr (C>A), Ser593Arg (C>G) and Glu491Lys (G>A) polymorphisms increased glioma risk in different degrees. CONCLUSION This meta-analysis suggested that XRCC1 Arg194Trp and XRCC1 Arg399Gln (G>A) polymorphisms led to susceptibility to glioma in Asian but not Caucasian population. XRCC1 Glu491Lys (G>A), Pro161Leu (C>T), Leu387Leu (G>A), Pro602Thr (C>A), Thr304Ala (A>G) and Ser593Arg (C>G) polymorphisms will increase glioma risk. However, XRCC1 Arg280His (G>A) is irrelevant to the increased or decreased glioma risk.