XPD Lys751Gln polymorphism is not associated with oral cancer risk: evidence from a meta-analysis.

Several studies have investigated the association between xeroderma pigmentosum group D (XPD) Lys751Gln polymorphism and oral cancer. However, the impact of XPD Lys751Gln polymorphism on oral cancer risk is unclear, owing to the obvious inconsistence among those studies. The aim of this study was to derive a more precise estimation of the association of XPD Lys751Gln polymorphism with oral cancer by performing a meta-analysis. Data were analyzed using Stata, and publication bias was estimated. We included seven study populations, comprising 1,093 cases and 2,637controls from seven publications. The pooled odds ratio (OR) with their 95 % confidence interval (95 % CI) was calculated to assess the association between XPD Lys751Gln polymorphism and risk of oral cancer. Overall, there was no association between XPD Lys751Gln polymorphism and oral cancer risk under all genetic models (Gln/Gln versus Lys/Lys: OR = 1.23, 95 % CI 0.78-1.96, p = 0.04; Lys/Gln + Gln/Gln versus Lys/Lys: OR = 1.13, 95 % CI 0.87-1.48, p = 0.03; Gln/Gln versus Lys/Gln + Lys/Lys: OR = 1.14, 95 % CI 0.79-1.63, p = 0.16; Lys/Gln versus Lys/Lys: OR = 1.12, 95 % CI 0.89-1.40, p = 0.131). Subgroup analysis by ethnicity suggested that there was no association between XPD Lys751Gln polymorphism and oral cancer risk in both Asians and Caucasians. These results suggest that XPD Lys751Gln polymorphism is not related to oral cancer risk. Further large and well-designed studies are required to confirm this conclusion.