GSTP1 and urinary bladder cancer: However, inconclusive results have been reported on the association between GSTP1 gene polymorphisms and the risk of bladder cancer: while a number of studies identified an obvious association between GSTP1 polymorphisms Ile105Val and bladder carcinoma risk [26–28], other studies illustrated that there are no association between GSTP1 Ile105Val polymorphism and bladder cancer [29, 30].