Glutathione S-transferase and multidrug-resistant phenotype in transitional cell carcinoma of the bladder.

Abstract

To asses the role of expression of resistance phenotypes in treatment failure in patients with invasive transitional cell carcinoma of the urinary bladder, since P-glycoprotein and glutathione S-transferase pi (GST) expression are implicated in resistance to various chemotherapy agents in different tumors. Tumor samples from P-glycoprotein and GST-pi were analyzed by immunohistochemistry. 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 expression of both proteins. No significant impact on prediction of tumor behavior was evident on statistical analysis by any one of the protein expressions. 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-glycoprotein or GST-pi expression appears to be of little value as a predictor of response to chemotherapy in this group of tumors.