prostate specific antigen: a protein, produced by the prostate, elevated levels of which may indicate the presence of cancer.
Examples from the web for PSA
This problem especially applies to prostate cancer and PSA screening.
British Dictionary definitions for PSA
PSA
abbreviation
1.
prostatic specific antigen: an enzyme secreted by the prostate gland, increased levels of which are found in the blood of patients with cancer of the prostate