Effects of glutathione S-transferase (GST) M1 and GSTT1 genotypes on urothelial cancer risk

The M1 member of the mu class of the glutathione S-transferase (GSTM1) gene is present in about 50% of individuals. GSTT1, a member of the theta class , which has been recently shown to be polymorphic, is expressed in 35-90% o f individuals. In this study, 145 Japanese patients with urothelial transit ional cell carcinoma and 145 healthy controls, frequency matched for age an d gender, were compared for frequencies of GSTM1 and GSTT1 genotypes. The u rothelial cancer risk increased due to the GSTM1 null genotype (odds ratio (OR) 1.71, 95% confidence interval (CI) 1.05-2.79). On the other hand, the OR tended to decrease due to the GSTT1 null genotype, although nor signific antly. Among individuals of the GSTM1 null genotype, those of the GSTT1 pos itive genotype had a two-fold risk (OR 2.62, 95% CI 1.36-5.05) compared wit h the GSTT1 null genotype (OR 1.25, 95% CI 0.62-2.51). A significant intera ction between the GSTM1 genotype and smoking status was found; the GSTM1 nu ll genotype was associated with an increased risk of urothelial cancer amon g smokers (OR 1.98, 95% CI 1.10-3.57). (C) 1998 Elsevier Science Ireland Lt d. All rights reserved.