Systematic review of the relationship between genetic polymorphism of cytochrome P450 2E1 at Ras I/Pst I loci and the susceptibility to lung cancer

Objective:To evaluate relationship between polymorphisms of cytochrome P4502E1 at RasⅠ/PstⅠ loci and susceptibity to lung cancer by means of Meta-analysis. Methods:Studies from 1991-2007 were retrieved through Cochrane Library,Medline,Elsevier,Ovid,Highwire Press,EMCC,CNKI,CBMdisk and VIP database without language limitation to collect relevant papers. Odds ratio of CYP2E1 genotype distributions in the group of patients with lung cancer and the group of healthy control was calculated. The Meta-analysis was applied with RevMan 4.2 software for heterogereity test and pooled OR calculation. Results:Nine case-control studies with 1 123 cases and 1 434 controls were analysed by fixed-effect meta-analysis method. The pooled odds ratio of CYP2E1 genotype c1/c1 vs c1/c2 +c2/c2 was 1.55(95%CI:1.30～1.86),Z statistics were 4.84. An association between CYP2E1 c1/c1 genotype and smoking was not found among cases. The pooled OR of interaction was 0.73(95%CI:0.45～1.15). Z statistics were 1.37. Conclusion:There was enough evidence currently to prove the relationship between CYP2E1 genetic polymorphism and susceptibility to lung cancer. It was demonstrated that the genetic polymorphism of CYP2E1 at RasⅠ/PstⅠ loci was the important risk factor for the susceptibility to human lung cancer, but there was not a definite interaction between the effects of smoking and CYP2E1 c1/c1 genotype on lung cancer risk.