These preliminary findings indicate that the c.1471G>A genetic polymorphism of XRCC1 has the potential to influence glioma susceptibility, and might be used as molecular marker for assessing glioma risk.
This study provides evidence that DNA repair genes ERCC1, ERCC2, and XRCC1 might be low-penetrance glioma-risk genes, while MGMT and PARP1 polymorphisms may confer protection against glioma.
To further evaluate gene-gene and gene-environment interactions on XRCC1 polymorphisms and glioma risk, thousands of subjects and tissue-specific biochemical characterizations are required.
Genetic variants found in DNA repair genes (ERCC1, rs3212986; ERCC2, rs13181; ERCC4, rs1800067; ERCC5, rs17655; XRCC1, rs1799782, rs25487, rs25489; XRCC3, rs861539) have been reported to have an ambivalent association with the development of glioma.
Nevertheless, large-scale, well-designed and population-based studies are needed to further evaluate gene-gene and gene-environment interactions, as well as to measure the combined effects of these XRCC1 variants on glioma risk.
The combined genotypes of XRCC1 AG or GG with PARP1 VA or AA, and XRCC1 AG or GG with PARP1 VV were more represented in the glioma patients (p = 0.001 and 0.003, respectively).
Yet, it is necessary to conduct future prospective explorations to gain a better insight into the impact of XRCC1Arg399Gln polymorphism on glioma risk.
This meta-analysis suggests that glioma susceptibility is associated with rs1799782 and rs25487 of X-ray repair complementing defective repair in Chinese hamster cells 1 (XRCC1), rs1805377 of XRCC4, rs1800067 of excision repair cross-complementing rodent repair deficiency complementation group 4 (ERCC4) and rs3212986 of ERCC1 in Asian population, and rs12917 of O-6-methylguanine-DNA methyltransferase (MGMT) and rs1136410 of poly(ADP-ribose) polymerase 1 (PARP1) in Caucasian population.
Odds ratios as well as their 95 % confidence intervals in three genetic models were used to estimate the strength of the association between XRCC1 genotypes and glioma risk.
A total of 11 studies (3,810 cases and 6,079 controls), 7 studies (2,928 cases and 5,048 controls), and 4 studies (1,461 cases and 2,593 controls) were finally included in the analyses of the association between XRCC1Arg399Gln, Arg194Trp, and Arg280His polymorphisms and glioma risk, respectively.
However, in pair-wise comparisons a few SNP combinations were associated with the risk of brain tumors: Among others, carriers of both homozygous variant genotypes, i.e., XRCC1 Gln399Gln and XRCC3 Met241Met, were associated with a three-fold increased risk of glioma (OR = 3.18; 95% CI, 1.26-8.04) and meningioma (OR = 2.99; 95% CI, 1.16-7.72).
In summary, we suggest that the XRCC1Arg194Trp genetic polymorphism could be a predictive biomarker for the susceptibility to glioma in a Chinese population.
When stratified by the grade of glioma, patients with WHO IV glioma had a significantly higher frequency of XRCC1 194 TT (OR = 1.60, 95 % CI = 1.02, 2.51; P = 0.04) and XRCC1 399 AA genotype (OR = 1.59, 95 % CI = 1.04, 2.42; P = 0.03).
Our comprehensive analysis of nine SNPs in eight genes suggests that the rs730437 and rs1468727 in ERGF, rs1799782 in XRCC1 gene, and rs861539 in XRCC3 gene are associated with glioma risk.
This study demonstrates that the rs25489 (Arg280His) and Arg399Gln (rs25487) polymorphisms in XRCC1 gene might influence the risk of developing glioma in Chinese population.
This meta-analysis was performed to derive a more precise estimation between XRCC1 polymorphisms (Arg399Gln, Arg194Trp, and Arg280His) and glioma risk.