Answer:
PSA: Prostate-specific antigen, also known as gamma-seminoprotein or kallikrein-3, P-30 antigen, is a glycoprotein enzyme encoded in humans by the KLK3 gene. PSA is a member of the kallikrein-related peptidase family and is secreted by the epithelial cells of the prostate gland.
THATS THE KNOLEDGE I FOUND IN MY ENCYLOPIDEA.