Association between the CYP2E1 polymorphisms and lung cancer risk: a meta-analysis.

The previous, published data on the association between CYP2E1 RsaI (rs2031920), DraI (rs6413432) polymorphisms and lung cancer risk remained controversial. Hence, we performed a meta-analysis to investigate the association between lung cancer and CYP2E1 RsaI (5,074 cases and 6,828 controls from 34 studies), and CYP2E1 DraI (2,093 cases and 2,508 controls from 16 studies) in different inheritance models. Overall, significantly decreased lung cancer risk was observed (dominant model: odds ratio (OR) 0.80, 95 % confidence interval (95 % CI) 0.71-0.90; heterozygote model: OR 0.80, 95 % CI 0.70-0.90; additive model: OR 0.82, 95 % CI 0.72-0.94) when all the eligible studies were pooled into the meta-analysis of CYP2E1 RsaI polymorphism. In further stratified and sensitivity analyses, significantly decreased lung cancer risk was found among Asians (dominant model: OR 0.81, 95 % CI 0.71-0.93; heterozygous model: OR 0.81, 95 % CI 0.69-0.95), population-based studies (dominant model: OR 0.69, 95 % CI 0.54-0.88; recessive model: OR 0.39, 95 % CI 0.16-0.91; additive model: OR 0.67, 95 % CI 0.53-0.84; homozygous model: OR 0.34, 95 % CI 0.14-0.80; heterozygous model: OR 0.70, 95 % CI 0.54-0.91), hospital-based studies (dominant model: OR 0.80, 95 % CI 0.69-0.93; additive model: OR 0.84, 95 % CI 0.70-1.00; heterozygous model: OR 0.80, 95 % CI 0.68-0.95), lung AC (heterozygous model: OR 0.84, 95 % CI 0.71-1.00), smokers (dominant model: OR 0.72, 95 % CI 0.55-0.94), and non-smokers (dominant model: OR 0.74, 95 % CI 0.61-0.91). There was no significant association between CYP2E1 DraI polymorphism and the risk of lung cancer when all the eligible studies were pooled into the meta-analysis. However, in further stratified and sensitivity analyses, significant association was observed among smokers (dominant model: OR 0.49, 95 % CI 0.35-0.69). In summary, this meta-analysis indicates that CYP2E1 RsaI polymorphism is associated with lung cancer risk among Asians, CYP2E1 RsaI polymorphism may be associated with lung adenocarcinoma risk, and CYP2E1 RsaI and DraI polymorphisms may be associated with decreased lung cancer risk in smokers.