Prognostic value of immunohistochemical expression of the c-erbB-2 oncoprotein in metastasic prostate cancer

It is well established that the activation of proto-oncogenes could trigger uncontrolled cell growth and cancer development. Although this correlation has already been evidenced in several human tumors, no conclusive studies have related oncogene activation with the development of prostatic neoplasi a, Nevertheless, some reports suggest that c-erbB-2, which is a prognostic marker in breast cancer, could be implicated in the development of prostati c adenocarcinoma. We have studied the expression of the c-erbB-2 oncoprotei n in primary prostatic tissue in a series of 70 patients with metastasic di sease, by means of immunohistochemistry. The NCL-B 11 anti-c-erbB-2 monoclo nal antibody was used, and the immunoreactivity was quantified by image ana lysis. The overall rate of prostatic-tissue sections presenting positive c- erbB-2 immunostaining was 64.3%. No significant relation was observed betwe en histological grade and c-erbB-2 overexpression or severity of the diseas e, based on the extent of metastases. The average specific survival in pati ents with c-erbB-2 over-expression was 33 months, while it was 54 in patien ts with c-erbB-2 negativity; p < 0.034. These results, as well as the logis tic-regression analysis, suggest that expression of c-erbB-2 oncoprotein wo uld be considered as an independent prognostic factor of metastatic prostat e cancer. Moreover, it could discriminate between the prognosis of patients with Gleason score 2 to 7 and those with score 8 to 10. Our results sugges t that the expression of c-erbB-2 oncoprotein in primary prostatic tissue c ould have a prognostic value in patients with metastatic prostate cancer. I nt. J. Cancer(Pred. Oncol.) 84:421-425, 1999. (C) 1999 Wiley-Liss, Inc.