CURRENT EVALUATION OF THE TISSUE LOCALIZATION AND DIAGNOSTIC UTILITY OF PROSTATE-SPECIFIC MEMBRANE ANTIGEN

BACKGROUND. Current statistics indicate that prostate carcinoma is the most common form of cancer diagnosed in American men, resulting in th e second highest cancer death rate. Early diagnosis and accurate stagi ng are imperative given that there is little effective treatment for m etastatic disease, especially after androgen deprivation therapy fails . Identification of new biochemical markers for disease progression wi ll provide important tools for diagnosis and monitoring. One such pote ntial marker is prostate specific membrane antigen (PSMA). METHODS. A review was conducted to identify reports concerning evaluation of diag nostic applications of PSMA. RESULTS. PSMA is a membrane-bound glycopr otein that is highly restricted to the prostate. Immunohistochemical f indings indicate that PSMA is a marker of epithelial cells of the pros tate. This expression is increased in association with prostate carcin oma, particularly in hormone-refractory disease. Given its membrane-bo und character, PSMA has been exploited as a marker for tumor detection by immunoscintiscanning with the In-111-labeled anti-PSMA monoclonal antibody 7E11.C5. Increased concentrations of 7E11.C5-reactive antigen are present in the serum of prostate carcinoma patients compared with healthy individuals; also, hematogenous circulating prostate carcinom a cells are detectable with reverse transcriptase-polymerase chain rea ction analysis with primers specific for PSMA. New monoclonal antibodi es specific for extracellular portions of the PSMA molecule currently are being utilized in applied studies. CONCLUSIONS. PSMA is a widely u sed marker for prostate epithelial cells. Its up-regulation in associa tion with cancer, particularly in advanced cancer, is ideal for applic ation as a prognostic marker. A variety of promising clinical applicat ions utilizing PSMA have been or are being developed. In the future, t hese promise to have an important impact on cancer diagnosis and patie nt treatment. (C) 1998 American Cancer Society.