XPC Ala499Val and XPG Asp1104His polymorphisms and digestive system cancer risk: a meta-analysis based on model-free approach.

Many studies have reported the association between XPC Ala499Val and XPG Asp1104His polymorphisms and digestive system cancer susceptibility, but the results were inconclusive. We performed a meta-analysis, using a comprehensive strategy based on the allele model and a model-free approach, to derive a more precise estimation of the relationship between XPC Ala499Val and XPG Asp1104His polymorphisms with digestive system cancer risk. For XPC Ala499Val, no significant cancer risk was found in the allele model (OR = 0.98, 95% CI: 0.86-1.11) and with model-free approach (ORG = 0.97, 95% CI: 0.83-1.13). For XPG Asp1104His, there was also no association between this polymorphism and cancer risk in the allele model (OR = 1.03, 95% CI: 0.96-1.11) and with the model-free approach (ORG = 1.04, 95% CI: 0.95-1.14). Therefore, this meta-analysis suggests that the XPC Ala499Val and XPG Asp1104His polymorphisms were not associated with digestive system cancer risk. Further large and well-designed studies are needed to confirm these findings.