[Purification and determination of human prostate specific antigen in the serum]

A human prostate specific antigen (PA) has been purified from an extract of prostatic tissue obtained during operation for benign prostatic hypertrophy (BPH). The antigen, which can be demonstrated a single component by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), has an apparent molecular weight of about 34,000 and has lower mobility for the positive pole than prostatic acid phosphatase (PAP). Double antibody radioimmunoassay (RIA) for PA in serum was developed with the antiserum raised in rabbit against partially purified PA. In normal serum of 30 controls the concentration were studied by the RIA. The normal upper limit of the serum PA levels in assay was set at 2.5 ng/ml. Elevated levels were observed in serum from 19 out of 21 untreated patients with prostatic carcinoma and 9 out of 23 patients with BPH, but latter less than 10 ng/ml. The results indicate that the PA is a potentially useful marker as well as PAP for prostatic cancer.