GLUTATHIONE-S-TRANSFERASE-PI EXPRESSION IN TRANSITIONAL-CELL CARCINOMA OF THE BLADDER

Glutathione-S-transferase pi (GSTpi) is a multifunctional protein that acts as an enzyme, involved in the detoxification of drugs and carcin ogens. It has been implicated both in drug resistance and malignant tr ansformation of epithelium. Using an indirect immunohistochemical tech nique, we have evaluated cytoplasmic and nuclear staining in normal ur othelium, 23 superficial bladder tumours and 26 invasive tumours. All 26 invasive tumours had been treated with platinum-based chemotherapy. Cytoplasmic staining was seen in normal urothelium and all bladder tu mours. Nuclear staining was seen in 1 superficial tumour and in 13 inv asive tumours. There was no association between nuclear staining and r esponse to chemotherapy. Nuclear staining was seen in 1 area of dyspla sia and in 2 of 3 areas of carcinoma in situ. GSTpi expression is not a predictor of response to chemotherapy. Increased intra-nuclear expre ssion of GSTpi may be associated with progression of transitional cell carcinoma of the bladder.