The present invention is directed to the use of antibodies or binding portions thereof, probes, ligands, or other biological agents which either recognize an extracellular domain of prostate specific membrane antigen or bind to and are internalized with prostate specific membrane antigen. These biological agents can be labeled and used for detection of normal, benign hyperplastic, and cancerous prostate epithelial cells or portions thereof. They also can be used alone or bound to a substance effective to ablate or kill such cells as a therapy for prostate cancer. Also disclosed are four hybridoma cell lines, each of which produces a monoclonal antibody recognizing extracellular domains of prostate specific membrane antigens of normal, benign hyperplastic, and cancerous prostate epithelial cells or portions thereof.