[Prostate-specific antigen (PSA): diagnostic and prognostic implications in the evaluation of carcinoma of the...

Prostatic specific antigen (PSA), glycoprotein with molecular weight of 34000, was first identified by Wang and Coll. in prostatic tissue initially; then Papsidero and Wang purified PSA in the sera of patients with prostatic cancer. We determined PSA concentration in 132 serum samples obtained from 111 patients affected by prostatic carcinoma: of these 61 had untreated prostatic cancer (6 had a stage A disease, 10 stage B, 19 stage C and 26 stage D) and 50 were variously treated (17 with cyproterone acetate, 11 with estramustine phosphate, 10 with LH-RH analogues, 9 underwent radical prostatectomy and 3 radiation therapy alone). Each patients was assigned a histological grade according to Gaeta, by means of a perineal transrectally guided prostatic biopsy. At periodical follow-ups of treated subjects, patients' state and neoplastic evolution were considered. Serum PSA has been measured by a competitive radioimmunoassay (PSA-Double antibody, Diagnostic Product Corporation) in which 125-I-labeled PSA competes with PSA in the samples for antibody sites. The antibody-bound fraction is then precipitated and counted. Since manipulation of the prostate gland may lead to elevated PSA levels, patients' samples were obtained prior to rectal examination, biopsy or surgical procedures. On the basis of a preliminary study of samples from healthy blood donors, we fixed the cut-off value at 2.9 ng/ml. In patients with untreated prostatic carcinoma PSA serum mean value was 26.33 ng/ml (range 0.5-100), resulting elevated in 56/61 (90,16%) patients.(ABSTRACT TRUNCATED AT 250 WORDS)