BACKGROUNDLung cancer is the leading cause of malignant tumor death among Chinese population. It has been known that the development of lung cancer may be associated with genetic po-lymorphism of some lung cancer related genes. The aim of this study is to evaluate the relationship between genetic polymorphism of metabolizing enzymes and susceptibility of lung cancer in Chinese population.

METHODSPolymorphism of CYP2E1 RsaI/PstI and GSTM1 was detected in 99 patients with lung cancer and 66 patients with benign pulmonary disease by PCR-RFLP and PCR. The association between genetic polymorphism and susceptibility of lung cancer was analyzed.

RESULTSNo significant difference in three RsaI/PstI genotype distribution of CYP2E1 was found between lung cancer group and control group (Chi-Square=1.374, P=0.241). (2) The frequency of GSTM1-null genotype in lung cancer group was significantly higher than that in control group (57.6% vs 40.9%, Chi-Square=4.401, P=0.036). (3) The individuals who carried with GSTM1-null genotype had a 1.96 fold increased risk of lung cancer (OR=1.96, 95%CI=1.042-3.689, P=0.037) than those who carried with GSTM1-present genotype. (4) When data were stratified by smoking status, the smokers who carried with c1/c1 genotype had a significantly higher risk of lung cancer (OR=3.525, 95%CI=1.168- 10.638, P=0.025) than those never-smokers who carried with at least one c2 allel. (5) When combination of polymorphism of CYP2E1 RsaI/PstI genotype and GSTM1 genotype was analyzed, compared with individuals who had concurrent present of GSTM1 and at least one c2 allel genotype, the risk of lung cancer for combination of GSTM1 null and c1/c1 genotype was increased significantly (OR=3.449, 95%CI=1.001- 11.886, P=0.050). Considering smoking status, compared with never-smokers who had concurrent present of GSTM1 and at least one c2 allel genotype, the risk of lung cancer for combination of GSTM1 null and c1/c1 genotype was remarkably increased (OR=11.553, 95%CI=1.068-124.944, P=0.044), as well as that for combination of GSTM1 null and at least one c2 allel genotype (OR=13.374, 95%CI=1.258-142.166, P= 0.032).

CONCLUSIONS(1)GSTM1 null genotype is an important factor associated with increased risk of lung cancer. (2) The combination of c1/c1 and GSTM1-null genotype can remarkably increase risk of lung cancer both in smokers and non-smokers.