On December 1, 2020, the U.S. Food and Drug Administration approved Gallium 68 PSMA-11 (Ga 69 PSMA-11) as the first drug for positron emission tomography (PET) imaging of PSMA-positive lesions in men with suspected metastatic disease or biochemical recurrence based on prostate-specific antigen elevation following prostate surgery or RT. Here, KLK3 is linked to metastatic neoplasm.