title: Instant-quality fluorescence in-situ hybridization as a new tool for HER2 testing in breast cancer: a comparative study.
abstract: OBJECTIVE
  HER2 instant-quality fluorescence in-situ hybridization (IQFISH) is a new fluorescence in-situ hybridization (FISH) assay developed with a non-toxic buffer that reduces the hybridization time to 1-2 h, enabling a turnaround time of 3 h 30 min from dewax to counting. The aim of this study was to compare assessment of HER2 status using IQFISH and assessment using standard FISH.
  
  
  RESULTS
  We selected 160 breast cancer samples according to their HER2 status as determined by immunohistochemistry (IHC) in a retrospective multicentre cohort (40 cases in each scoring category, i.e. 0/1+/2+/3+). Each participating site (n = 5) constructed its tissue microarray (TMA) of 32 archival cases and sent it to the central site (site 1). HER2 IHC, HER2 FISH and HER2 IQFISH were performed blindly at site 1. IQFISH provided excellent quality signals without any background staining, thus allowing excellent reading conditions even on TMA. Statistical analysis showed almost perfect agreement between IQFISH and FISH (99.3%, κ = 0.98). The only discordant case was an equivocal one with an HER2/CEP17 ratio near the ASCO/CAP cut-off.
  
  
  CONCLUSIONS
  The highly concordant data support IQFISH as a useful alternative to FISH, allowing reliable assessment of HER2 status. Use of this method could lead to reporting of HER status to the oncologist within a day.
authors.affiliation: Pathology Department, Institut Claudius Regaud, Toulouse, France.
authors.forename: Camille
authors.initials: C
authors.lastname: Franchet
authors.forename: Thomas
authors.initials: T
authors.lastname: Filleron
authors.forename: Anne
authors.initials: A
authors.lastname: Cayre
authors.forename: Eveline
authors.initials: E
authors.lastname: Mounié
authors.forename: Frédérique
authors.initials: F
authors.lastname: Penault-Llorca
authors.forename: Jocelyne
authors.initials: J
authors.lastname: Jacquemier
authors.forename: Gaëtan
authors.initials: G
authors.lastname: Macgrogan
authors.forename: Laurent
authors.initials: L
authors.lastname: Arnould
authors.forename: Magali
authors.initials: M
authors.lastname: Lacroix-Triki
mesh_terms: D001943:Breast Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D012189:Retrospective Studies; D046888:Tissue Array Analysis
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human
keywords: biomarker; breast cancer; gene amplification; immunohistochemistry; in-situ hybridization; predictive marker