C-ERBB-2 ONCOPROTEIN - A POTENTIAL BIOMARKER OF ADVANCED PROSTATE-CANCER

BACKGROUND. Overexpression of the c-erbB-2 oncogene has been implicate d in the development and/or prognosis of several human carcinomas, inc luding that of the prostate. Recently, c-erbB-2 protein was found to b e released in the circulation. The present study was undertaken to stu dy the significance of serum c-erbB-2 protein determination in men wit h prostate cancer. METHODS. Serum c-erbB-2 protein determination was p erformed via immunoradiometric assay using two monoclonal antibodies t hat react with the extracellular domain of the protein. The study popu lation consisted of 71 untreated prostate cancer patients. Of those, 3 3 with stage D2 disease entered a follow-up study. As control, serum c -erbB-2 protein levels were determined in 92 patients with benign pros tatic hypertrophy. In addition, elevations of c-erbB-2 protein were ex amined in patients with various disease statuses: clinically well cont rolled (28 patients), disease progression (24 patients), and end-stage disease (17 patients). RESULTS. Elevation of serum c-erbB-2 protein l evel was observed in patients in advanced stages, such as stage D2 dis ease (30%), disease progression (42%), and end-stage disease (82.4%). In the follow-up study, patients with an elevated c-erbB-2 level had a significantly shorter interval to disease progression than did those with a normal level. CONCLUSIONS. The results suggest that c-erbB-2 ca n be used as a biomarker to identify a malignant subgroup in prostate cancer. (C) 1997 Wiley-Liss, Inc.