Evaluation of HER-2/neu (erbB-2) status in breast cancer: From bench to bedside

Molecular alterations irm breast cancer are being incorporated into the dev elopment of new treatment strategies. The HER-2/neu oncogene has been exten sively investigated as a prognostic factor and recently as a predictor of r esponse to chemotherapy or endocrine therapy. The development of a humanize d anti-HER-2 monoclonal antibody (Herceptin) and the encouraging results ob tained in the treatment of patients with HER-2 overexpressing metastatic br east cancer with this antibody have resulted in renewed interest in HER-2/n eu. This article reviews the current knowledge of HER-2/neu both as a progn ostic and a predictive factor. Problems associated with the standardization of the methodology for assessing HER-2/neu status and clinically significa nt cut-off points are addressed.