Limitations in the use of glutathione S-transferase P1 in urine as a marker for bladder cancer.

Background: GST pi (GSTPI) is overexpressed in bladder cancer and desquamation of the tumour may produce detectable levels of urinary GSTPI which could be used as a marker for the early diagnosis of bladder cancer. Materials and Methods: A preliminary study in 27 transitional cell carcinoma (TCC) patients and 20 controls, using an ELISA methodl is presented here. Results: 55.5% of TCC patients were positive for GSTPI, while all control samples were negative. Some of the GSTPI positive cases also gave positive results for haematuria, which indicates that a limitation of this marker involves the contamination of the urine with erythocyte GSTPI. In 5 cases (18.5%) without haematuria detectable levels of GST pi were found. Conclusions: Further studies would be required to assess the advantages of this technique over clas sical cytology or as a complement to it, especially in patients in a phase of temporary negative haematuria.