Resumen de Expression of prostate specific membrane antigen (PSMA) in prostatic adenocarcinoma and prostatic intraepithelial neoplasia

C. Marchal, M. Redondo, M. Padilla, J. Caballero, I. Rodrigo, J. García, J. Quian, D.G. Boswick

• The prostatic membrane antigen (PSMA) is a protein that is expressed in the prostatic epithelium. We studied the expression of PSMA in a series of 55 patients with different stages of prostate cancer and we compared the PSMA staining in prostate cancer cells, in high-grade prostatic intraepithelial neoplasia (PIN) and in histologically benign prostatic epithelium for the same specimen. For this purpose archival paraffin-embedded specimens were studied by immunohistochemistry with a monoclonal antibody 7E11-C5.3 against PSMA using the streptavidin-biotin method. The mean percentage of PSMA immunoreactivity was 56.67% in prostate cancer (CaP) cells, and 48.6% in PIN cells, which was significantly higher than benign-appearing prostatic epithelium (5.72%) (for each pair, p<0.001). PSMA expression was greater in CaP with a higher Gleason score (p=0.01), but no relationship was found with serum PSA value. We conclude that PSMA overexpression is detected in high-grade PIN and is associated with a higher Gleason score of prostate cancer. It is a potential marker for studying carcinogenesis and progression of prostate cancer.