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Human epidermal growth factor receptor 2 testing in gastric carcinoma: issues related to heterogeneity in biopsies and resections *
Author(s) -
Lee Stephen,
de Boer Willem Bastiaan,
Fermoyle Soraya,
Platten Michael,
Kumarasinghe Marian Priyanthi
Publication year - 2011
Publication title -
histopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.626
H-Index - 124
eISSN - 1365-2559
pISSN - 0309-0167
DOI - 10.1111/j.1365-2559.2011.04017.x
Subject(s) - immunohistochemistry , pathology , dysplasia , concordance , carcinoma , biopsy , medicine , cancer , epidermal growth factor receptor , human epidermal growth factor receptor 2 , breast cancer
Lee S, de Boer W B, Fermoyle S, Platten M & Kumarasinghe M P
(2011) Histopathology 59 , 832–840 Human epidermal growth factor receptor 2 testing in gastric carcinoma: issues related to heterogeneity in biopsies and resections Aims: To assess human epidermal growth factor receptor 2 (HER2) status and heterogeneity using immunohistochemistry (IHC) and silver in‐situ hybridization (SISH) in gastric carcinoma and dysplasia, and to correlate HER2 status between biopsy and resection specimens of gastric carcinoma. Methods and results: Immunohistochemistry for HER2 was performed in 178 cases of gastric carcinoma, and SISH in cases showing at least 1+ reaction. HER2 positivity [European Medicines Agency (EMA) guidelines] was identified in 20.2% of carcinomas and 12.9% of high‐grade dysplasia, and HER2 heterogeneity noted in 50% and 33% of these cases, respectively. IHC negative/positive reactivity and SISH results were concordant in 96.2%. SISH amplification was seen in 35.3% of IHC 2+ and in a case with previously unrecognized staining pattern. Concordance of IHC HER2 status on biopsies and gastrectomies was seen in 74.1%. False negative IHC results on either the biopsy or gastrectomy were seen in 19.4% of HER2 amplified cases. Conclusions: Human epidermal growth factor receptor 2 status in gastric carcinoma is comparable to previous studies with good concordance between IHC and SISH; all IHC 2+ and unusual patterns should be assessed with ISH studies; heterogeneity of tumour HER2 overexpression/amplification is common with possible implications for HER2 testing; and HER2 overexpression appears sufficiently specific to be considered a potential diagnostic biomarker of dysplasia.