Cytochrome P450 2E1 RsaI/PstI polymorphism is associated with urologic cancer risk: evidence from a meta-analysis

Cytochrome P450 2E1 (CYP2E1) is involved in the metabolic activation of various carcinogens. CYP2E1 RsaI/PstI polymorphism has been identified in urologic cancer patients, while studies of the polymorphism have shown inconclusive trends in the risk of urologic cancers. Therefore, we performed this systematic review to provide a complete picture and conducted a meta-analysis to derive a precise estimation. We searched PubMed, Embase and Web of Science to identify eligible studies up to December 15, 2014. 12 studies with 2712 cases and 2977 controls were included in the meta-analysis. The odds ratio with a 95% confidence interval was used to assess the strength of associations. We observed that the c2 allele of CYP2E1 RsaI/PstI polymorphism was associated with a decreased risk of urologic cancer under all genetic models (c2 vs. c1: OR = 0.742, 95% CI = 0.659-0.835); c2c2 vs. c1c1: OR = 0.516, 95% CI = 0.357-0.745; c1c2 vs. c1c1: OR = 0.748, 95% CI = 0.748 (0.648-0.863; c2c2 + c1c2 vs. c1c1: OR = 0.722, 95% CI = 0.629-0.829; c2c2 vs. c1c1 + c1c2: OR = 0.578, 95% CI = 0.401-0.832). In the subgroup analysis by cancer type, statistically significant associations were found in urothelial cancer in all genetic models. When stratified by ethnicity, a same trend was also indicated in Asians in all genetic models. To conclude, our results support the conclusion that the CYP2E1 RsaI/PstI polymorphism may be associated with urologic cancer susceptibility. The c2 allele is a low-penetrance risk factor for urologic cancer development.