Lung cancer risk and genetic polymorphism at the glutathione S-transferase P1 locus in male Japanese

The glutathione S-transferases (GSTs) are widely expressed in mammalian tissues and involved in Phase II detoxification reactions. The GSTs form a supergene family consisting of four distinct families, named alpha (GSTA), mu (GSTM) theta (GSTT) and pi (GSTP). Several of the GST genes are polymorphic in humans and are currently being investigated as possible cancer-risk modifiers. Among the GST genes, we examined GSTP1 polymorphism in exon 5 among male lung cancer patients (n = 86, male Japanese) and male healthy controls (n = 80, male Japanese) by restriction fragment length polymorphism-polymerase chain reaction method. The cancer patients showed frequency of the GSTP1 mutated genotype (individuals having at least one mutant allele, 29.1%) very similar to that of the control subjects (28.8%). After adjusting for smoking status, no association was found between the GSTP1 mutated genotype and lung cancer risk (odds ratio: 0.95; 95% confidence interval: 0.48-1.90). When study subjects were divided into two subgroups based on smoking status, the GSTP1 mutated genotype was not associated with an increased risk of lung cancer among smokers and non-smokers. These results suggest that GSTP1 polymorphism in exon 5 alone may not increase the risk of lung cancer in male Japanese.