Her-2/neu expression in breast cancer--A comparison of different diagnostic methods.

BACKGROUND Determination of Her-2/neu overexpression in breast cancer has previously been shown to be of prognostic significance. In this study, Her-2/neu expression in breast cancer was characterised by real-time PCR (RLT-PCR) based LightCycler-HER-2/neu DNA Quantification with immunohistochemistry (IHC) and fluorescence in situ hybridisation (FISH). MATERIAL AND METHODS Fifteen specimens of invasive breast cancer - whole tissue sections as well as microdissected tumour cells - were subjected to RLT-PCR. Additionally, IHC and FISH were performed. RESULTS Her-2/neu overexpression was detected by FISH and by real-time PCR in the same tumours. In contrast, IHC revealed discordant results. CONCLUSION Determination of Her-2/neu amplification by real-time PCR is a sensitive and specific method with some advantages over FISH. This method is simple and reliable and has the potential of categorizing those tumours with borderline Her-2/neu overexpression as determined by IHC.