Efforts are increasing to identify and evaluate diagnostic and therapeutic markers for prostate cancer patients. One of these, prostate-specific membrane antigen (PSMA), a transmembrane protein highly expressed in all types of prostatic tissue (eg, benign epithelium, benign prostatic hyperplasia, prostatic intra-epithelial neoplasia and adenocarcinomas, with increased binding affinity for malignant cells), is becoming an increasingly important diagnostic and therapeutic marker, not only for prostate cancer, but possibly for other malignant lesions. Recent studies have demonstrated PSMA expression in endothelial cells of tumor-associated neovasculature (including carcinoma of the colon, breast, bladder, pancreas, kidney and melanoma), thus greatly expanding its possible beneficial role, especially as new anti-PSMA mAbs continue to be developed and refined. Future diagnostic and therapeutic interventions utilizing these antibodies will become increasingly important in not only prostate cancer but perhaps many other different malignancy types.