The expression of Prostate-specific membrane antigen (PSMA) mRNA was assessed in the normal bladder urothelium (n = 9), transitional cell carcinoma (TCC) specimens (n = 52), TCC-derived cell lines (n = 3), and preoperative blood 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 detected in normal (n = 3) and malignant tissues (n = 4). Using a PSMA-specific substrate, PSMA enzymatic activity was found in two bladder cell lines and correlated with immunostaining. Seven of the 27 TCC preoperative blood samples were positive by reverse transcription-PCR. These preliminary results, obtained on a nonrandomized cohort of patients, correlated with tumor invasion (positive RT-PCR: 0% for pT < or = 2 versus 41% for pT > or = 3) and 2-year survival rate (81% in the PSMA-negative group versus 29% in the PSMA-positive group). Although the clinical usefulness of this assay requires confirmation in larger prospective randomized 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.
Gala, Jean-Luc ; Loric, S ; Guiot, Yves ; Denmeade, S R ; Gady, A ; et. al. Expression of prostate-specific membrane antigen in transitional cell carcinoma of the bladder: prognostic value?. In: Clinical cancer research : an official journal of the American Association for Cancer Research, Vol. 6, no. 10, p. 4049-54 (2000)