by Dana-Farber Cancer Institute Credit: Pixabay/CC0 Public Domain Like the better-known prostate-specific antigen (PSA), prostate-specific membrane antigen (PSMA) is a biomarker that can tell physicians much about a patient’s metastatic prostate cancer. PSMA is a protein on the cell surface of most prostate cancers; scanning for it with positron emission tomography (PET) can indicate where...