Evaluation of c-erbB-2 Expression, Amplification, and Prognostic Value in Primary and Metastatic Prostate Adenocarcinomas

Objective: The c-erbB-2 gene codes for a membrane receptor protein that is homologous to the epidermal growth factor receptor. It has been established as a prognostic factor in breast and other cancers. The prognostic role of c-erbB-2 expression and gene amplification in prostate carcinoma is still controversial. In this study, we searched for c-erbB-2 overexpression and gene amplification in primary and metastatic prostate carcinomas and their correlation with tumor grade, age, and survival. Material and Methods: c-erbB-2 protein overexpression was analyzed on 59 prostate carcinomas, including 44 primary and 15 metastatic prostate carcinomas, by immunohistochemistry and fluorescence in situ hybridization analysis. Results: When divided into two Gleason grade categories, there were 20 low-grade and 24 high-grade cases in the primary prostate carcinoma cases. C-erbB-2 overexpression was detected in 13.6% of primary and in 60% of metastatic prostate carcinomas. The overexpression was correlated with Gleason score (p=0.001) and clinical outcome but not with age (p 0.05). None of the cases showed HER-2 amplification by FISH. Conclusion: In this study, c-erbB-2 protein overexpression was associated with high grade and advanced pathological stage. Additionally, it was also associated with metastatic prostate tumors. These findings support that this marker indicates a potentially aggressive clinical course and metastasis. Therefore, this marker may be helpful for planning therapy.