Analysis of GSTM1, GSTT1, GSTP1, and TP53 polymorphisms as genetic risk factors for bladder cancer in the Turkish population

Abstract

The effect of the GSTM1 and GSTT1 null genotypes, the GSTP1 Ile105Val, and TP53 Arg72Pro polymorphism on bladder cancer susceptibility was investigated in a case control study of 121 bladder cancer patients, and 121 age-sex matched controls in the Turkish population. The adjusted odds ratio (for age, sex, and smoking status) for the GSTM1 null genotype is 1.94 (95% CI 1.15- 3.26) and for the GSTP1 105 Ile/Val or Val/Val genotypes is 1.75 (95% CI 1.03- 2.99). GSTT1, and TP53 loci was not shown to be associated with bladder cancer. Combination of the two high risk genotypes, GSTM1 null and GSTP1 105 Ile/Val or Val/Val, revealed that the risk increases by 3.91 times (95% CI 1.88-8.13) when compared with the combination of the low risk genotypes of these loci. In individuals with a combined risk of cigarette smoking and the GSTM1 null genotype, bladder cancer risk is 2.81 (95% CI 1.23-6.35) relative to persons who do not smoke and carry the GSTM1 present genotype. The same risk for the GSTP1 105 Ile/Val or Val/Val genotypes is 2.38 (95% CI 1.12-4.95). These findings support the role for the GSTM1 null and the GSTP1 105 Ile/Val or Val/Val genotypes in the development of bladder cancer. Furthermore, gene-gene (GSTM1- GSTP1) and gene-environment (GSTM1-smoking, GSTP1-smoking) interactions increase this risk substantially.