Diagnostic and Therapeutic Applications of PSMA in Prostate Cancer

Neal Shore, MD: Interestingly, to think about PSMA [prostate-specific membrane antigen] now as an antigenic expression, we have to go back and look historically at how we were wedded to acid phosphatase as the key expressive assay back in the 1970s and 1980s, and even arguably in the 1960s. Then we developed PSA, prostate-specific antigen, and PSA has been key to evaluating not just diagnosis, but more importantly, responses to therapy. PSMA is prostate-specific membrane antigen, and it’s perhaps a bit of a misnomer because it presents on many other areas within the body, not just the prostate. There’s PSMA expression in vascular tissue, it presents in the kidney and salivary glands, as well as clearly in the prostate and metastatic deposits from prostate cancer. 

PSMA is a transmembrane antigen, being both extra and intracellular, and has the advantages of demonstrating areas of disease. Now, with the new improved next-generation imaging, the PSMA PET [positron emission tomography] scans, we can pick up or assess disease that heretofore on a lower macroscopic level we could not discern with conventional imaging, traditionally CT scan and technetium bone scan. Thus, with PSMA now we’re able to identify areas of disease that heretofore we could not appreciate. Then, because of its transmembrane facilitation, we’re able to use therapeutic payloads to create apoptotic effects, and that’s a really important area. In addition to the diagnostic imaging capability, we now have the ability to attach antibody to the PSMA with associated payloads, traditionally now in the form of radiopharmaceuticals, which can have a therapeutic effect where prostate cancer cells exist. 

TRANSCRIPT EDITED FOR CLARITY