ADH1C Ile350Val Polymorphism and Cancer Risk: Evidence from 35 Case-Control Studies

Background: Alcohol dehydrogenase 1C (ADH1C) is the key enzyme catalyze oxidation of alcohol to acetaldehyde, which plays vital roles in the etiology of various cancer. To date, studies investigated the association between a functional polymorphism in ADH1C, Ile350Val (rs698), and risk of cancer have shown inclusive results. Methods: A meta-analysis based on 35 case-control studies was performed to address this issue. Odds ratios (OR) with 95% confidence intervals (CIs) were used to assess the association. The statistical heterogeneity across studies was examined with chi 2-based Q-test. Results: Overall, no significant associations between ADH1C Ile350Val polymorphism and cancer risk were observed in any genetic models (P > 0.05). In the stratified analyses, there was a significantly increased cancer risk among African (Val/Val vs. Ile/Ile OR = 2.19, 95% CI = 1.29-3.73, P-heterogeneity = 0.989; Ile/Val + Val/Val vs. Ile/Ile: OR = 1.79, 95% CI = 1.18-2.71, P-heterogeneity = 0.761; Val/Val vs. Ile/Val + Ile/Ile: OR = 1.92, 95% CI = 1.16-3.17, P-heterogeneity = 0.981) and Asian ( Ile/ Val vs. Ile/ Ile: OR = 1.58, 95% CI = 1.32-1.90, P-heterogeneity = 0.375; Val/Val vs. Ile/Ile: OR = 3.84, 95% CI = 1.74-8.49, P-heterogeneity = 0.160; Ile/Val + Val/Val vs. Ile/Ile: OR = 1.65, 95% CI = 1.38-1.96, P-heterogeneity = 0.330; Val/Val vs. Ile/Val + Ile/Ile: OR = 3.54, 95% CI = 1.62-7.75, P-heterogeneity = 0.154) studies. Conclusions: The results indicate that ADH1C Ile350Val polymorphism may contribute to cancer risk among Africans and Asians. Additional comprehensive system analyses are required to validate this association combined with other related polymorphisms.