Serial measurements of tissue polypeptide specific antigen (TPS), PSA, PAP and CEA serotest values in treated patients with primary and metastatic prostate cancer.

Blood tissue polypeptide specific antigen (TPS) concentration was serially measured by IRMA radioimmunodetective procedure in hormonally treated prostate cancer patients with Stage Do-D1 tumor (20 subjects free of bone lesions) and Stage D2 disease (20 subjects with bone metastases). Monoclonal antibody against the principle M3-TPA epitope was used in this TPS assay. Serum TPS values were compared with respective blood prostate specific antigen (PSA), prostatic acid phosphatase (PAP), carcinoembryonic antigen (CEA) and testosterone levels in a retrospective manner. A control group included healthy men, patients with benign prostatic hypertrophy (BPH), subjects with inflammation of the prostate, and men with diabetes. PSA is reported to be a quantitative calibration for prostate cancer load in untreated patients, especially during early stages of the disease. In hormonally treated, advanced, and dedifferentiated prostatic carcinoma this serotest fails to reflect properly both tumor status and response to treatment. In Stage Do-D1 patients TPS concentrations remain normal or become slightly elevated even during local tumor progression. This finding is in accord with the slow proliferation of nonaggressive primary tumors. Circulating TPS concentrations are elevated in progressive metastatic patients, in the majority of Stage D2 subjects with stable disease and even in some of these patients during partial tumor remission. This latter result may be attributed not only to the heterogeneity of the advanced prostatic cancer but also to the actual tumor response to treatment, since serum PSA level fails to reflect properly the outcome of hormonal treatment. There is some evidence that an abrupt elevation in serum TPA level in such patients is a consequence of NK cell-mediated lysis of circulating tumor cells, thus giving rise to a simultaneous and rapid delivery of intracellular TPS into the bloodstream. Prostatic inflammation elevates TPS concentrations only slightly, while diabetes, even during a proper treatment, raises TPS concentration more intensely. In patients with BPH normal or slightly increased TPS values were measured. The results ot these preliminary investigations seem to open the way for further prospective studies.