Introduction: Prostate specific membrane antigen (PSMA) has become a target for radionuclide imaging and therapy. Previous studies have shown that the expression of PSMA is not specific to prostate tissue. In this study we examine the expression of PSMA in urothelial cell carcinoma (UCC).
Methods: Immunhistochemical PSMA-staining was performed in 89 UCC samples. PSMA expression in tumor tissue, adjacent healthy tissue and blood vessels was examined. We furthermore analyzed PSMA-mRNA expression in nine human UCC cell lines. We correlated our findings with clinical data regarding recurrence and progression of UCC.
Results: UCC tissue showed a significantly higher PSMA expression compared to healthy urothelial tissue (p < 0.001). Non muscle invasive bladder cancer revealed significantly higher PSMA expression compared to muscle invasive bladder cancer (p < 0.05). PSMA expression significantly differed between various T-stages (p < 0.05) and tumor differentiation (p < 0.001). In four human UCC cell lines PSMA-mRNA was detectable. Those patients who suffered recurrence showed a higher rate of PSMA expression but no correlation to recurrence-free survival was evident. Progression of disease correlated significantly with a higher PSMA expression (p = 0.036).
Conclusions: Both UCC tissue and healthy urothelial tissue express PSMA, with significantly higher levels in UCC. We confirmed these findings in human UCC cell lines. In this small first cohort expression of PSMA correlates significant with progression of disease but not with recurrence and recurrence-free survival. These first results make PSMA a promising target for future diagnosis and therapy of UCC.
Keywords: Prostate specific membrane antigen; Tumor marker; Urothelial cell carcinoma.