Association between CYP2E1 polymorphisms and colorectal cancer risk: a systematic review and meta-analysis

CYP2E1 encodes an enzyme that participates in the activation of several carcinogenic substances. Thus, numerous studies have investigated the association between CYP2E1 polymorphisms and colorectal cancer (CRC) risk, but inconclusive results have been obtained. We performed a meta-analysis to precisely evaluate the relationship of CYP2E1 rs2031920, rs3813867, and rs6413432 polymorphisms with the susceptibility to CRC. Scopus, Web of Science and PubMed databases were searched to identify eligible studies, and the association between the polymorphisms and CRC risk was then quantitatively synthesized using different genetic models. Eighteen studies with 23,598 subjects were selected for inclusion into the analysis. Significant association between rs2031920 and an increased CRC risk was observed in homozygous (OR = 1.496, 95% CI 1.177-1.901, P = 0.001), recessive (OR = 1.467, 95% CI  1.160-1.857, P = 0.001) and allele (OR = 1.162, 95% CI  1.001-1.349, P = 0.048) models. Significant association was not found for rs3813867 and rs6413432 (P > 0.05). In conclusion, our results suggest that rs2031920, but not rs3813867 and rs6413432, is associated with the risk of CRC.