GLUTATHIONE-S-TRANSFERASE AND MULTIDRUG-RESISTANT PHENOTYPE IN TRANSITIONAL-CELL CARCINOMA OF THE BLADDER

Objective: To asses the role of expression of resistance phenotypes in treatment failure in patients with invasive transitional cell carcino ma of the urinary bladder, since P-glycoprotein and glutathione S-tran sferase pi (GST) expression are implicated in resistance to various ch emotherapy agents in different tumors. Methods: Tumor samples from P-g lycoprotein and GST-pi were analyzed by immunohistochemistry. Results: P-glycoprotein and GST-pi were found in 35.7 and 42.9% of the samples , respectively, In 21.4% of the samples there was simultaneous express ion of both proteins, No significant impact on prediction of tumor beh avior was evident on statistical analysis by any one of the protein ex pressions, Conclusion: Drug resistance in transitional cell carcinoma may be through different mechanisms. Although the small sample size of this study precludes firm conclusions, the assessment of P-glycoprote in or GST-pi expression appears to be of little value as a predictor o f response to chemotherapy in this group of tumors.