A UK NEQAS ICC and ISH multicentre study using the Kreatech Poseidon HER2 FISH probe: intersite variation can be rigorously controlled using FISH.
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.
Bartlett
John M S
JM
Endocrine Cancer Group, Edinburgh University Cancer Research Centre, Western General Hospital, Edinburgh, UK. john.bartlett@ed.ac.uk
Campbell
Fiona M
FM
Ibrahim
Merdol
M
Thomas
Jeremy
J
Wencyk
Pete
P
Ellis
Ian
I
Kay
Elaine
E
Connolly
Yvonne
Y
O'Grady
Anthony
A
Barnett
Sarah
S
Starczynski
Jane
J
Cunningham
Paul
P
Miller
Keith
K
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