| Amplification of the HER2 gene in breast cancers testing 2+ weak positive by HercepTest immunohistochemistry: false-positive or false-negative immunohistochemistry? | |
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MedLine Citation:
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PMID: 16822876 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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BACKGROUND: The majority of cases of breast cancer scoring HER2 weak positive (2+) on immunohistochemistry (IHC) using the HercepTest are not associated with amplification of the HER2/neu gene. AIM: To examine the reproducibility of IHC in cases scoring 2+ subsequently shown to have gene amplification by fluorescence in-situ hybridisation (FISH). METHODS: A retrospective analysis of 153 cases referred for FISH confirmation of a weak positive HercepTest (2+) result was performed. Repeat IHC was undertaken in cases with weak positive (2+) referral IHC and amplification of the HER2 gene by FISH. RESULTS: Amplification of the HER2 gene was confirmed in 29/153 cases (19%) scoring 2+ on IHC. Repeat IHC was carried out on 25 IHC 2+ cases: 7 (28%) scored 2+ on repeat IHC, 18 (72%) scored 3+ and were reclassified as strong positive. A heterogeneous expression pattern was present in 3/17 cases scoring 3+. CONCLUSIONS: The majority of HercepTest 2+ results are not accompanied by gene amplification and represent "false positive" IHC in terms of prognostic or therapeutic relevance. A small proportion of HercepTest 2+ scores represent true 2+ IHC positive cases accompanied by gene amplification: a category probably biologically related to 3+ IHC cases. The remainder of cases of HercepTest 2+ accompanied by gene amplification represent a category of referral IHC 2+ weak positive, FISH amplified, repeat IHC 3+ strong positive, best described as "false negative 2+ IHC". This has implications for selection of cases for FISH analysis where weak positive (2+) IHC score is used as a triage for FISH testing, and for testing strategies in referral laboratories undertaking FISH analysis. |
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Authors:
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Ciara Barrett; Hilary Magee; Denise O'Toole; Sinead Daly; Michael Jeffers |
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Publication Detail:
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Type: Journal Article Date: 2006-07-05 |
Journal Detail:
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Title: Journal of clinical pathology Volume: 60 ISSN: 0021-9746 ISO Abbreviation: J. Clin. Pathol. Publication Date: 2007 Jun |
Date Detail:
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Created Date: 2007-06-11 Completed Date: 2007-07-26 Revised Date: 2010-09-14 |
Medline Journal Info:
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Nlm Unique ID: 0376601 Medline TA: J Clin Pathol Country: England |
Other Details:
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Languages: eng Pagination: 690-3 Citation Subset: AIM; IM |
Affiliation:
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Department of Cellular Pathology, The Adelaide and Meath Hospital, Tallaght, Dublin 24, Ireland. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Breast Neoplasms
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genetics*,
metabolism,
pathology False Negative Reactions False Positive Reactions Female Genes, erbB-2 Humans Immunohistochemistry In Situ Hybridization, Fluorescence Neoplasm Invasiveness Neoplasm Proteins / metabolism Receptor, erbB-2 / metabolism* Retrospective Studies Tumor Markers, Biological / metabolism* |
| Chemical | |
Reg. No./Substance:
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0/Neoplasm Proteins; 0/Tumor Markers, Biological; EC 2.7.10.1/Receptor, erbB-2 |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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