CYP1A1 MspI polymorphism and susceptibility to lung cancer in the Chinese population: an updated meta-analysis and review

Background: Although many epidemiologic studies have investigated the CYP1A1 MspI gene polymorphisms and their associations with lung cancer (LC), definite conclusions cannot be drawn. Objective: To clarify the effects of CYP1A1 MspI polymorphisms on the risk of LC, an update meta-analysis was performed in only Chinese population. Methods: Related studies were identified from PubMed, Springer Link, Ovid, Chinese Wanfang Data Knowledge Service Platform, Chinese National Knowledge Infrastructure (CNKI), and Chinese Biology Medicine (CBM) till October 2014. Pooled ORs and 95% CIs were used to assess the strength of the associations. Results: A total of 22 studies including 3016 LC cases and 3932 controls were involved in this meta-analysis. Overall, significant association was found between CYP1A1 MspI polymorphism and LC risk when all studies in the Chinese population pooled into this meta-analysis (CC vs. TT: OR = 1.42, 95% CI = 1.11-1.80; CT + CC vs. TT: OR = 1.26, 95% CI = 1.06-1.50; CC vs. CT + TT: OR = 1.30, 95% CI = 1.04-1.61; C vs. T: OR = 1.21, 95% CI = 1.07-1.37). In subgroup analyses stratified by ethnicity and source of controls, significantly increased risk was found in Chinese Han people and in population-based studies. Conclusions: This meta-analysis provides the evidence that CYP1A1 MspI polymorphism may contribute to the LC development in the Chinese population and studies with large sample size and wider spectrum of population are warranted to verify this finding.