prostate-specific antigen n a protease that is secreted by the epithelial cells of the prostate and is used in the diagnosis of prostate cancer since its concentration in the blood serum tends to be proportional to the clinical stage of the disease abbr. PSA
* * *
(PSA) a serine endopeptidase secreted by the epithelial cells of the prostate gland; serum levels are elevated in benign prostatic hyperplasia and prostate cancer. Measurement of PSA serum levels is used as a screening test for prostate cancer.Medical dictionary. 2011.