An immunohistochemical demonstration of C-erbB-2 oncoprotein expression in prostatic adenocarcinoma

Choi, Jong Bo; Cheon, Jun; Kim, Han Kyeum; Kim, Je Jong; Ko, Sung Kun

Abstract

The c-erbB-2 gene is located on q21 of chromosome 17. The c-erbB-2 oncoprotein exhibits tyrosine kinase activity, appears to be a receptor for to yet unidentified growth factor and has been demonstrated in a number of cancers by immunohistochemical as well as matrix blotting techniques. Breast and ovarian cancer patients, whose tumor cells have amplification or overexpression or this oncoprotein, have been suggested to have worse prognosis. But there were only a few reports on c-erbB-2 oncoprotein expression in prostatic carcinoma. The aim of this study was to ex- amine the c-erbB-2 oncoprotein expression in pnstatic adenocarcinoma to assess its potential as a useful prognostic marker in this disease. The samples were considered immunoreactive when distinct cell membrane was slained. These staining pattern was noted exclusively in neoplastic cells and was unirormly distributed throughout the neoplastic cell population. Incidence of c-erbB-2 oncoprotein expression in Gleason grade 4 and 5 prostatic adenocarcinoma is significantly higher than that in Gleason grade 1, 2 and 3(Chi-square test, p<0.05), and incidence in stage D prostatic adenocarcinoma is significantly higher than that in stage A, B and C(Chi-square test, p<0.25). But there is no significant difference of c-erbB-2 oncoprotein expression according to DNA ploidy or proliferation index by flow cytometry. High proliferating cell nuclear antigen(PCNA) expression rate is not associated with c-erbB-2 oncoprotein expression. The results of this study suggest that the c-erbB-2 oncoprotein together with other predictive parameters may serve to provide a phenotypic profile which permits more accurate forecasting of prostatic cancer behavior, and may prove useful in the future as an important guide for directing speciric anti-tumor therapy. To investigate these possibilities, further studies based on larger numbers or cases with complete follow up data will be needed.