Expression of prostate-specific membrane antigen in transitional cell carcinoma of the bladder: Prognostic value?

The expression of Prostate-specific membrane antigen (PSMA) mRNA was assess ed in the normal bladder urothelium (n = 9), transitional cell carcinoma (T CC) specimens (n = 52), TCC-derived cell lines (n = 3), and preoperative bl ood samples from TCC patients (n = 27), Specific PSMA mRNA was found in 100 % of normal and malignant tissues and two cell lines. PSMA protein was dete cted in normal (It = 3) and malignant tissues (n = 4), Using a PSMA-specifi c substrate, PSMA enzymatic activity was found in two bladder cell lines an d correlated with immunostaining, Seven of the 27 TCC preoperative blood sa mples were positive by reverse transcription-PCR, These preliminary results , obtained on a nonrandomized cohort of patients, correlated with tumor inv asion (positive RT-PCR: 0% for pT less than or equal to 2 versus 41% for pT greater than or equal to 3) and 2-year survival rate (81% in the PSMA-nega tive group versus 29% in the PSMA-positive group). Although the clinical us efulness of this assay requires confirmation in larger prospective randomiz ed trials, current preliminary results suggest that a blood-borne PSMA mRNA PCR assay may be a useful tool to predict a poor outcome in TCC patients.