INTRODUCTION: The overexpression of human epidermal growth factor receptor (HER-2/neu) protein and the amplification of its gene are indicators of more aggressive behavior in breast cancer. The Food and Drug Administration (FDA) has approved HercepTest® with the goal of selecting patients to be elegible for treatment with the humanized murine monoclonal antibody anti-HER-2/neu (trastuzumab). AIMS: The aim of the present study was to compare the results of HER-2/neu expression using routine immunohistochemistry method LSAB®+ (Dakocytomation polyclonal antibody A0485) and HercepTest®. MATERIAL AND METHODS: 50 cases of breast carcinoma previously evaluated for HER-2/neu expression by routine immunohistochemistry using the LSAB+ method were included. These cases were also evaluated for HER-2/neu expression using HercepTest® for comparison. Results: 34 cases of breast carcinoma were negative for HER-2/neu expression by the two methods, with score 0 by HercepTest®. In 12 and 22 cases, respectively, score 1+ and 0 were observed by the LSAB®+ method. In eight cases, score 2+ was present by both methods. Score 3+ was found in eight cases also by both methods. DISCUSSION: The most common method used in routine clinical practice to determine HER-2/neu status is immunohistochemistry. Variability of HER-2/neu results can be caused by a number of variables including time of fixation, methods of epitope retrieval and type of primary antibodies used. CONCLUSION: The conclusion of the present study was that LSAB®+ and HercepTest® revealed equivalent results for HER-2/neu expression in breast carcinoma.
Carcinoma; Breast; C-erbB-2; HER-2/neu; Overexpression; Immunohistochemistry
