title: Comparison of HER2 immunohistochemical results using a monoclonal antibody (SV2-61γ) and a polyclonal antibody (for Dako HercepTest) in advanced gastric cancer.
abstract: We compared a monoclonal antibody (SV2-61γ) and a polyclonal antibody (Dako HercepTest) in immunohistochemical assessments of human epidermal growth factor receptor 2 (HER2) expression in 73 samples of advanced gastric cancer. Results were scored as 0 to 3+, and equivocal or discordant (SV2-61γ/Dako HercepTest = 0/2+, 0/3+, 1+/3+ or 2+/3+) cases were subjected to fluorescence in situ hybridization (FISH) analysis. The frequencies of HER2 scores of 2+ or 3+ were 15.1% (11/73) using SV2-61γ and 38.4% (28/73) using Dako HercepTest. All of the equivocal or discordant cases with a HER2 score of 3+ using Dako HercepTest exhibited amplification of the HER2 gene regardless of the HER2 score determined with SV2-61γ. The results of the HER2 tests differed according to the antibodies used for immunohistochemistry that preceded FISH analysis, being 15.1% (11/73) using SV2-61γ and 23.3% (17/73) using Dako HercepTest. Thus, therapeutic decisions might be markedly influenced by the selection of antibody used in the HER2 test.
authors: Department of Pathology and Laboratory Medicine, Yamagata Prefectural Central Hospital, Yamagata, Japan. gtamura@ypch.gr.jp
authors: Gen
authors: G
authors: Tamura
authors: Mitsumasa
authors: M
authors: Osakabe
authors: Naoki
authors: N
authors: Yanagawa
authors: Shin-ya
authors: SY
authors: Ogata
authors: Takashi
authors: T
authors: Nomura
authors: Norimasa
authors: N
authors: Fukushima
authors: Yoshimasa
authors: Y
authors: Ito
authors: Minori
authors: M
authors: Tabuchi
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D014408:Biomarkers, Tumor / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D017404:In Situ Hybridization, Fluorescence; D011933:Reagent Kits, Diagnostic; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D013194:Staining and Labeling; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology
chemical_list: D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor; D011933:Reagent Kits, Diagnostic; D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human