Association between glutathione S-transferase M1 and T1 polymorphisms and increased risk for bladder cancer in Korean smokers.

We evaluated the relationship between polymorphisms in the GSTM1 and GSTT1 genes and smoking status in a case-controlled study of a Korean population. The GSTM1 and GSTT1 genotypes were determined using a polymerase chain reaction (PCR)-based method and prognostic factors, such as staging and grading were evaluated for 126 bladder cancer patients, and 204 control subjects. Smoking represented a high-risk factor (odds ratio (OR)=4.8, 95% confidence interval (CI)=2.9-8.0) for the patients with bladder cancer. The frequency of GSTM1 null individuals was higher than in the controls, but the differences were not statistically significant (OR=1.56, 95% CI=2.9-8.0). For Korean subjects who smoked more than 1 pack of cigarettes per year (PPY), the increased risk of bladder cancer was associated with the GSTM1 null genotype (OR=0.5, 95% CI=0.3-0.9). Low-stage bladder tumors were more common among the GSTM1 null genotypes (OR=2.3; 95% CI=1.1-5.5). This study suggests that in Korean subjects the GSTM1 null genotype may be associated with increased risk for bladder cancer, in a manner that appears to depend upon smoking status. And also, in bladder cancer patients the GSTM1 null genotype appears to be associated with a poorer prognosis with low stage bladder tumors.