Lack of association between CYP1A1 polymorphisms and risk of bladder cancer: a meta-analysis.

The effects of CYP1A1 gene polymorphisms on the risk of bladder cancer (BC) remain controversial. We carried out a meta-analysis to clarify the role of CYP1A1 gene polymorphisms in BC. A comprehensive literature search was conducted up to November 20, 2013. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to estimate the strength of the association. Meta-regression, subgroup analysis, sensitivity analysis and publication bias were also performed. Eight studies involving 1,059 BC cases and 1,061 controls were included. The meta-analysis showed that there was no significant association between the two common mutations of CYP1A1 and BC risk. For the I1e462Val A/G polymorphism with GG vs. AA the OR was 1.47 (95 % CI= 0.70-3.07, P =0.308). For the MspI T/C polymorphism, though a slight trend was found this was not statistically nonsignificant (CC vs.TT, OR = 1.24, 95 % CI= 0.98-1.58, P =0.078). Subgroup analyses by ethnicity also found no obvious association between CYP1A1 and BC risk. The present meta-analysis suggests that CYP1A1 polymorphism is not associated with bladder cancer risk.