HER-2/neu evaluation by immunohistochemistry and fluorescence in situ hybridization in breast cancer: implications for daily laboratory practice.

BACKGROUND: HER-2/neu status was determined by immunohistochemistry (IHC) and fluorescence in situ hybridisation (FISH) methods in more than 300 paraffin-embedded primary breast cancer samples. MATERIALS AND METHODS: HER-2/neu status was determined by FISH using the PathVysion kit (Vysis) and by IHC using either a monoclonal antibody CB11 or a cocktail of antibodies: the monoclonal TAB250 and the polyclonal pAb1. RESULTS: Of the 324 cases evaluable by IHC, 65 out of 318 (20%) and 24 out of 324 (7%) were scored as positive when using the antibody cocktail and the CB11, respectively. HER-2/neu gene amplification occured in 64 out of 324 cases (20%). Concordance of FISH and IHC was found in 285 out of 318 cases (90%) and 278 out of 324 cases (86%) using the cocktail and the CB11, respectively. CONCLUSION: The cost-effectiveness analysis revealed that the use of a sensitive IHC method followed by confirmation of positive results by FISH considerably decreased the FISH costs and may become standard practice for HER-2/neu evaluation.

HER2: a 'predictive factor' ready to use in the daily management of breast cancer patients?

The past few years have witnessed an exponential increase in studies trying to identify molecular markers in patients with breast tumours that might predict for the success or failure of hormonal therapy or chemotherapy. HER2, a tyrosine kinase membrane receptor of the epidermal growth factor receptor family, has been the most widely studied marker in this respect. This paper attempts to critically review to what extent HER2 may improve 'treatment individualisation' for the breast cancer patient. Copyright (C) 2000.