ABSTRACT
HER-2/neu status is used as a marker for Herceptin\® therapy. The aim of this study was to evaluate the usefulness of quantitative real-time PCR (qPCR) in determining the HER-2/neu amplification status of breast cancer, by comparing qPCR, CISH, and chromogenic in-situ hybridization (CISH) and immunohistochemistry (IHC) results from the same samples. Thirty breast carcinomas were examined using the three methods. Twenty-two tumors were 2+ or 3+ positive with IHC, while eight samples were either completely negative or 1+. Fifteen positive and twelve negative cases were detected by both CISH and qPCR, which led to similar results. Comparison of CISH and qPCR together with IHC showed that qPCR was more sensitive in detecting HER-2/neu gene amplification in tumors scored as 2+ with IHC. In conclusion, qPCR may serve as useful alternative to CISH for detecting HER-2/neu gene amplification in breast-cancer patients. (Thai Cancer J 2010;30:104-111)