Genetic polymorphism of xenobiotic metabolizing enzymes among Chinese lungcancer patients

Polymorphisms in xenobiotic metabolizing enzymes have been implicated in in ter individual and inter-ethnic differences in cancer susceptibilty, Severa l studies have indicated an association between variant alleles of the huma n CYP1A1, CYP2E1 and GSTM1 genes and lung cancer. Activity of micro somal e poxide hydrolase (HYL1) has also been associated with lung cancer, and 2 va riant alleles causing amino acid substitutions have been described. We have investigated genetic polymorphisms of the CYP1A1, CYP2E1, GSTM1 and HYL1 g enes in 76 Chinese lung cancer patients and 122 healthy Chinese subjects. T he allele frequency of the CYP1A1*2B allele was 0.21 among lung cancer pati ents and 0.20 in the reference group, whereas the corresponding values for the CYP1A1*2A allele were 0.34 and 0.36, The CYP2E1*5B and CYP2E1*6 alleles were less frequent among the cancer patients (0.20 and 0.22) compared with healthy subjects (0.25 and 0.26), The frequency distribution of the HYL1*2 allele was 0.49 among lung cancer patients and 0.42 in the reference group , and the corresponding frequencies for the HYL1*3 allele were 0.13 and 0.1 0, The homozygous GSTM1*0 genotype was found in 64% of lung cancer patients and in 66% of healthy subjects. Among heavy smokers, the frequency was 73% . The differences in the distribution of variant CYP1A1, CYPZEI and GSTM1 a lleles in lung cancer patients and healthy controls were not statistically significant, Our results indicate that the polymorphisms investigated are o f minor importance as genetic susceptibility markers for lung cancer in thi s population. An increased risk for lung cancer in subjects carrying the HY L*3 allele was observed and suggests that polymorphism in this gene might p ossibly be a susceptibility factor in the Chinese population. (C) 1999 Wile y-Liss, Inc.