title: A UK NEQAS ICC and ISH multicentre study using the Kreatech Poseidon HER2 FISH probe: intersite variation can be rigorously controlled using FISH.
abstract: OBJECTIVE
  To assess a new HER2 fluorescence in situ hybridization (FISH) test and report on multicentre intrasite and intersite variation.
  
  
  RESULTS
  HER2 results were scored from 45 breast cancers in eight laboratories using the Kreatech Poseidon HER2 FISH probe (Kreatech Diagnostics, Amsterdam, the Netherlands). Overall, 80.9% of cores were successfully analysed. Mean intrasite variation for HER2 ratio assessment was low (4.74%). Intersite variation in ratio was in line with previous reports (11.9+/-0.8%) for both reference and non-reference laboratories; only one laboratory displayed significantly higher intersite variation (P=0.009) than the remaining seven laboratories. The overall incidence of misclassification of cores was <1.3%, demonstrating an excellent level of concordance (>98.7%) across all eight laboratories, irrespective of whether they were 'reference' or 'routine diagnostic' laboratories.
  
  
  CONCLUSIONS
  The Kreatech Poseidon HER2 FISH test is robust and reproducible. Highly quantitatively reproducible FISH results were obtained from eight 'diagnostic' and 'reference' laboratories; however, continued quality assessments are essential to good performance.
authors.affiliation: Endocrine Cancer Group, Edinburgh University Cancer Research Centre, Western General Hospital, Edinburgh, UK. john.bartlett@ed.ac.uk
authors.forename: John M S
authors.initials: JM
authors.lastname: Bartlett
authors.forename: Fiona M
authors.initials: FM
authors.lastname: Campbell
authors.forename: Merdol
authors.initials: M
authors.lastname: Ibrahim
authors.forename: Jeremy
authors.initials: J
authors.lastname: Thomas
authors.forename: Pete
authors.initials: P
authors.lastname: Wencyk
authors.forename: Ian
authors.initials: I
authors.lastname: Ellis
authors.forename: Elaine
authors.initials: E
authors.lastname: Kay
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Connolly
authors.forename: Anthony
authors.initials: A
authors.lastname: O'Grady
authors.forename: Sarah
authors.initials: S
authors.lastname: Barnett
authors.forename: Jane
authors.initials: J
authors.lastname: Starczynski
authors.forename: Paul
authors.initials: P
authors.lastname: Cunningham
authors.forename: Keith
authors.initials: K
authors.lastname: Miller
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics*; D005260:Female; D020869:Gene Expression Profiling / Q000379:methods / Q000592:standards*; D018734:Genes, erbB-2; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods / Q000592:standards*; D010338:Pathology, Clinical / Q000379:methods / Q000592:standards*; D015203:Reproducibility of Results; D046888:Tissue Array Analysis; D006113:United Kingdom