Genetic Variant Arg399Gln G>A of XRCC1 DNA Repair Gene Enhanced Cancer Risk Among Indian Population: Evidence from Meta-analysis and Trial Sequence Analyses.

The X-ray repair cross-complementation group 1 (XRCC1) gene plays an important role in base excision repair pathway. Several studies have reported contradictory results for XRCC1 exon 10 (Arg399Gln, G23990A, rs25487) gene polymorphism and cancer risk in Indian population, making it difficult to interpret them. Therefore, we have conducted a meta-analysis to evaluate the more precise association between XRCC1 exon 10 G>A gene polymorphism and risk of cancer by published studies. We searched PubMed (Medline) and Google scholar web databases to cover all studies published on association between XRCC1 exon 10 G>A gene polymorphism and cancer risk until August 2016. Pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) were used to appraise the strength of association. Heterogeneity, publication bias and sensitivity analysis were also assessed. Twenty-five published studies had fulfilled the inclusion criteria comprising 4131 confirmed cancer cases and 5013 controls. When all studies were polled together, overall significant association was found between XRCC1 exon 10 G>A polymorphism and cancer risk in variant allele carrier (A vs. G: OR 1.217, 95% CI 1.056-1.402, p = 0.007), homozygous (AA vs. GG: OR 1.359, 95% CI 1.036-1.783, p = 0.027), dominant (AA+AG vs. GG OR 1.208, 95% CI 1.006-1.450, p = 0.043) and recessive (AA vs. AG+GG: OR 1.315, 95% CI 1.029-1.680, p = 0.029) genetic models. Further sensitivity analysis supported the stability of our result by showing similar ORs before and after removal of a single study. The present meta-analysis suggested that the XRCC1 exon 10 G>A polymorphism contribute cancer risk in Indian population, and supports that individuals with risk allele A and AA genotype are at higher risk of developing cancer.