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

Abstract

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.