PURIFICATION AND ENZYME IMMUNOASSAY OF TUMOR MARKERS FOR PROSTATE CANCER: PROSTATIC ACID PHOSPHATASE, PROSTATESPECIFIC ANTIGEN AND CREATINE KINASE BB

Abstract

Prostatic acid phosphatase (PAP), prostate-specific antigen (PA) and creatine kinase BB (CK-BB) were purified from human prostate, and single components with molecular weights of about 50K, 35K and 40K daltons were shown on SDS-polyacrylamide gel electrophoresis. Prostate homogenate gave a single precipitin arc with each antisera on immunoelectrophoresis. By indirect immunofluorescent technique all of these antigens were present in the cytoplasm of prostatic epithelial cells. Fibronectin (FN) was isolated from normal plasma and its antisera were obtained. Enzyme immunoassays for PAP, PA, CK-BB and FN were established.
Prostate homogenate contained 83.7% of CK-BB in activity, and the antibody against the purified CK-BB cross-reacted to CK-MB from prostate homogenate. High levels of CK-BB were detected in sera from patients with hormone-controlled prostate cancer and benign prostatic hyperplasia after transurethral resection, despite normal PAP and PA concentrations. No correlation was seen among the three in serum levels of patients with prostate cancer.
Hormone-chemotherapy (vincristine, Ifosfamide and peplomycin) brought about normalization of CK-BB levels in sera from patients with stage D prostate cancer, and CK-BB, therefore, seemed to be a useful follow-up marker.
Prostate-specific antigen had two peaks (100K and 35K) in gel chromatography of prostate homogenate.
Radioimmunoassay (RIA), solid-phase immunoadsorbent assay (SPIA) or EIA for _PAP showed a different profile from one another in ion-exchange and and gel chromatography of some patient's serum with advanced prostate cancer. RIA also detected immuno-reactive substances which were not measured by SPIA and EIA, and the stabilization effect of PAP activity by antisera was suggested to increase the sensitivity in SPIA.