Correlation of cell proliferation marker (TPS), natural killer (NK) activity and tumor load serotest (PSA) in untreated and treated prostatic tumors.

Tissue polypeptide specific antigen (TPS) is a new tumor proliferation serotest marker. The respective radioimmunodetective procedure is based on the application of monoclonal antibodies raised against one the principle epitopes of tissue polypeptide antigen (TPA). TPS is useful tool for the identification of proliferative epithelial cells and is negative in all non-epithelial tissues such as lymph nodes, bone marrow, carcino-sarcomic and neuroendocrine prostatic tumors. In previous studies we have shown the clinical usefulness of this serotest in serial measurements during prostate cancer monitoring. In this study serum prostatic specific antigen (PSA) concentrations and natural killer (NK) cell activity data were compared with serum TPS values in a wide spectrum of prostate cancer condition (99 patients), benign prostatic hypertrophy (BPH, 40 patients), atypical prostate (12 subjects) and in 8 healthy men. Measured parameters reflect different aspects of the disease. Blood PSA concentrations and TPS serotest values were found to denote the status of disseminated prostate cancer with nearly equal significance, while PSA appears to be a more appropriate tumor marker in early stages of the disease. In atypical prostate a nonsignificant elevation of both PSA and TPA values were recorded when compared with BPH. In parallel, a pronounced and sharp drop in NK activity data was assessed resembling closely respective data in progressive Stage D2 patients. TPS serotest clearly detects cancer progression in treated and untreated patients (P < 0.01) while being less efficient in distinguishing between tumor stabilization and partial remission (p > 0.05). In this respect NK activity data serve as a sensitive probe for the presence of epithelial tumor cells in the circulation even during stabilization of the disease. According to the reported results we advocate the application of the TPS serotest as a useful addition in monitoring progressive patients with advanced prostatic carcinoma.