| Abstract: | Hwang C‐C, Pintye M, Chang L‐C, Chen H‐Y, Yeh K‐Y, Chein H‐P, Lee N & Chen J‐R
(2011) Histopathology 59 , 984–992 Dual‐colour chromogenic in‐situ hybridization is a potential alternative to fluorescence in‐situ hybridization in HER2 testing Aim: Dual‐colour chromogenic in‐situ hybridization (dc‐CISH) is an emerging methodology for characterizing genomic alterations. This study was aimed at evaluating the performance of a dc‐CISH kit (ZytoVision) in determining human epidermal growth factor receptor 2 (HER2) status in breast cancer. Methods and results: Two hundred and twenty‐eight invasive breast carcinomas arranged in tissue microarrays were analysed in parallel with dc‐CISH, fluorescence in‐situ hybridization (FISH), and immunohistochemistry. Of 227 tumours with available FISH and dc‐CISH results, HER2 amplification and non‐amplification were detected in 49 (21.6%) and 178 (78.4%) tumours, respectively, by both assays. The concordance between dc‐CISH and FISH results showed 100% agreement (κ‐coefficient = 1.00). Immunohistochemically, 162 (71%), 25 (11.0%) and 41 (18%) tumours were scored 0/1+, 2+, and 3+, respectively. The corresponding results with both FISH and dc‐CISH demonstrated HER2 amplification in two (3.2%), nine (36%) and 38 (93%) tumours, respectively. Complete consensus among these three methods was observed in 197 cases, representing 98% of all 3+ and 0/1+ tumours (κ‐coefficient = 0.92). Confirmatory testing of 25 2+ tumours showed complete consensus between FISH and dc‐CISH. Conclusions: dc‐CISH is a promising alternative to FISH in HER2 testing, and the single‐institute incidence of HER2 amplification in breast cancer in Taiwan is 21.2%. |
