Publication Year: 2000 Visited: 48

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Her-2-Neu (HER2) Overexpression in Locally Advanced Breast Cancer (LABC) as Measured by Quantitative Immunohistochemical (IHC) Analysis. C Wallace, S Day, A Kallab, A Jillella, K Yeh, R Dalton, Medical Coll of Georgia, Augusta, GA.

Although treatment with a recombinant humanized monoclonal antibody (rhuMAb HER2, transtzumab) to the HER2 receptor has been shown to be beneficial in women with metastatic disease whose tumors overexpress HER2, the role of such therapy in the adjuvant or neoadjuvant setting has not been defined. We sought to determine the potential efficacy of such neoadjuvant therapy in women with LABC by retrospectively testing paraffin-embedded specimens from primary tumors with a commercially available quantitiative immunohistochemical test for overexpression of HER2 (HercepTest, Dako). 74 women with clinical or pathologic T3NOMO, T3 N1-2MO, or T4N1-2MO tumors were identified through the tumor registry. Sufficient material was available for testing in 61 women. Paraffin blocks from primary tumor were then stained. Intensity of immunostaing was scored 0-1+ (negative) or 2-3+ (positive) according the guidelines and using internal controls. Patients were group into Stages (IIB, IIIA, or IIIB) and by immunohistochemical staining (negative 0-1+, or positive 2-3+). Overall, 23% (14/61) tumors overexpressed HER2 oncogene as defined by 2-3+ immunostaining. This did not vary by stage. [table] Overexpression of HER2 does not appear to be more common in LABC than has been previously reported in primary or metastatic tumors. It appears unlikely that the HER2 oncogene is somehow uniquely involved in the pathogenesis of LABC and biological therapy directed at H2n is therefore unlikely to be more or less useful in such patients.