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Comparison of different commercial kits for HER2 testing in breast cancer: looking for the accurate cutoff for amplification

INTRODUCTION: Accurate determination of human epidermal growth factor receptor 2 (HER2) status is essential for optimal patient management with trastuzumab (Herceptin). However, standard guidelines do not specify a particular commercial kit, antibody or probe for testing, and discrepancies arise fro...

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Autores principales: Cayre, Anne, Mishellany, Florence, Lagarde, Nicole, Penault-Llorca, Frédérique
Formato: Texto
Lenguaje:English
Publicado: BioMed Central 2007
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2242659/
https://www.ncbi.nlm.nih.gov/pubmed/17908324
http://dx.doi.org/10.1186/bcr1770
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author Cayre, Anne
Mishellany, Florence
Lagarde, Nicole
Penault-Llorca, Frédérique
author_facet Cayre, Anne
Mishellany, Florence
Lagarde, Nicole
Penault-Llorca, Frédérique
author_sort Cayre, Anne
collection PubMed
description INTRODUCTION: Accurate determination of human epidermal growth factor receptor 2 (HER2) status is essential for optimal patient management with trastuzumab (Herceptin). However, standard guidelines do not specify a particular commercial kit, antibody or probe for testing, and discrepancies arise from variability between kits. The aim of this study was to compare the accuracy of four commercially available fluorescence/chromogenic in situ hybridisation (FISH/CISH) kits and validate one for the resolution of borderline immunohistochemistry (IHC) cases. The interpretation pitfalls, optimal threshold values, assay duration and complexity of each kit were also considered. METHODS: The Food and Drug Administration (FDA)-approved dual-probe FISH assay PathVysion was chosen as the 'gold standard' against which pharmDx (dual-probe) and INFORM (mono-probe) FDA-approved FISH kits and the SPoT-Light CISH kit were compared. Tumours were also evaluated by IHC with the FDA-approved HercepTest kit and a validated in-house IHC protocol. Fifty-five patients with invasive breast carcinoma were selected as a representative proportion of HER2 IHC 2+ cases. RESULTS: HER2 amplification was observed in 31% of tumours by PathVysion compared with 33% with pharmDx. The number of amplified tumours detected by INFORM and CISH varied with the threshold applied. Agreement was excellent between PathVysion and pharmDx (100%), good with SPoT-Light (89%; cutoff at least five signals per nucleus) and moderate with INFORM (76%; cutoff more than four signals per nucleus). Agreement with INFORM improved to 98% with a cutoff of at least six signals per nucleus. CONCLUSION: With an appropriate cutoff, the INFORM kit was comparable to dual-probe FISH kits for evaluating HER2 status. We validate and recommend CISH as an appropriate assay for HER2 scoring that is easy to interpret and requires equipment readily found in, or that can be adapted to, all pathology laboratories. For borderline IHC cases, dual-probe FISH analysis remains the most useful protocol to apply.
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spelling pubmed-22426592008-02-14 Comparison of different commercial kits for HER2 testing in breast cancer: looking for the accurate cutoff for amplification Cayre, Anne Mishellany, Florence Lagarde, Nicole Penault-Llorca, Frédérique Breast Cancer Res Research Article INTRODUCTION: Accurate determination of human epidermal growth factor receptor 2 (HER2) status is essential for optimal patient management with trastuzumab (Herceptin). However, standard guidelines do not specify a particular commercial kit, antibody or probe for testing, and discrepancies arise from variability between kits. The aim of this study was to compare the accuracy of four commercially available fluorescence/chromogenic in situ hybridisation (FISH/CISH) kits and validate one for the resolution of borderline immunohistochemistry (IHC) cases. The interpretation pitfalls, optimal threshold values, assay duration and complexity of each kit were also considered. METHODS: The Food and Drug Administration (FDA)-approved dual-probe FISH assay PathVysion was chosen as the 'gold standard' against which pharmDx (dual-probe) and INFORM (mono-probe) FDA-approved FISH kits and the SPoT-Light CISH kit were compared. Tumours were also evaluated by IHC with the FDA-approved HercepTest kit and a validated in-house IHC protocol. Fifty-five patients with invasive breast carcinoma were selected as a representative proportion of HER2 IHC 2+ cases. RESULTS: HER2 amplification was observed in 31% of tumours by PathVysion compared with 33% with pharmDx. The number of amplified tumours detected by INFORM and CISH varied with the threshold applied. Agreement was excellent between PathVysion and pharmDx (100%), good with SPoT-Light (89%; cutoff at least five signals per nucleus) and moderate with INFORM (76%; cutoff more than four signals per nucleus). Agreement with INFORM improved to 98% with a cutoff of at least six signals per nucleus. CONCLUSION: With an appropriate cutoff, the INFORM kit was comparable to dual-probe FISH kits for evaluating HER2 status. We validate and recommend CISH as an appropriate assay for HER2 scoring that is easy to interpret and requires equipment readily found in, or that can be adapted to, all pathology laboratories. For borderline IHC cases, dual-probe FISH analysis remains the most useful protocol to apply. BioMed Central 2007 2007-10-01 /pmc/articles/PMC2242659/ /pubmed/17908324 http://dx.doi.org/10.1186/bcr1770 Text en Copyright © 2007 Cayre et al; licensee BioMed Central Ltd. http://creativecommons.org/licenses/by/2.0 This is an open access article distributed under the terms of the Creative Commons Attribution License ( (http://creativecommons.org/licenses/by/2.0) ), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research Article
Cayre, Anne
Mishellany, Florence
Lagarde, Nicole
Penault-Llorca, Frédérique
Comparison of different commercial kits for HER2 testing in breast cancer: looking for the accurate cutoff for amplification
title Comparison of different commercial kits for HER2 testing in breast cancer: looking for the accurate cutoff for amplification
title_full Comparison of different commercial kits for HER2 testing in breast cancer: looking for the accurate cutoff for amplification
title_fullStr Comparison of different commercial kits for HER2 testing in breast cancer: looking for the accurate cutoff for amplification
title_full_unstemmed Comparison of different commercial kits for HER2 testing in breast cancer: looking for the accurate cutoff for amplification
title_short Comparison of different commercial kits for HER2 testing in breast cancer: looking for the accurate cutoff for amplification
title_sort comparison of different commercial kits for her2 testing in breast cancer: looking for the accurate cutoff for amplification
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2242659/
https://www.ncbi.nlm.nih.gov/pubmed/17908324
http://dx.doi.org/10.1186/bcr1770
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