title: Dual-colour chromogenic in-situ hybridization is a potential alternative to fluorescence in-situ hybridization in HER2 testing.
abstract: OBJECTIVE
  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.
  
  
  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%.
authors.affiliation: Department of Pathology, Chang Gung Memorial Hospital, Keelung, Taiwan.
authors.forename: Cheng-Cheng
authors.initials: CC
authors.lastname: Hwang
authors.forename: Mariann
authors.initials: M
authors.lastname: Pintye
authors.forename: Liang-Che
authors.initials: LC
authors.lastname: Chang
authors.forename: Huang-Yang
authors.initials: HY
authors.lastname: Chen
authors.forename: Kun-Yan
authors.initials: KY
authors.lastname: Yeh
authors.forename: Hui-Ping
authors.initials: HP
authors.lastname: Chein
authors.forename: Nin
authors.initials: N
authors.lastname: Lee
authors.forename: Jim-Ray
authors.initials: JR
authors.lastname: Chen
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism*; D002863:Chromogenic Compounds; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization / Q000379:methods*; D017404:In Situ Hybridization, Fluorescence; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis* / Q000096:biosynthesis / Q000235:genetics; D015203:Reproducibility of Results; D046888:Tissue Array Analysis
chemical_list: D014408:Biomarkers, Tumor; D002863:Chromogenic Compounds; D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human