title: Application of the 2013 ASCO/CAP guideline and the SISH technique for HER2 testing of breast cancer selects more patients for anti-HER2 treatment.
abstract: The aim of this study is to assess the impact of changes of the 2013 ASCO/CAP guideline on the results of HER2 testing in breast cancer. A series of 916 primary invasive breast cancer cases, assessed as HER2 2+ by IHC in part using the 2007 and in part the 2013 ASCO/CAP criteria, was evaluated for HER2 amplification status by SISH and classified according to both 2007 and 2013 ASCO/CAP ISH guideline criteria. We observed a significant increase of HER2-positive cases (12.4 to 16.8%) and a decrease of HER2-equivocal cases (3.6 to 0.7%). Of the cases studied, 52.1% fulfilled both criteria of HER2/CEP17 ratio and average HER2 copy number per cell to be classified as HER2-positive. Reclassification of the cases from before the introduction of the new ASCO/CAP guideline with the 2013 ISH criteria resulted in an increase of cases with a HER2-positive status (12.4 to 14.2%) and in a decrease of HER2-equivocal cases (3.6 to 1.6%). The 2013 ASCO/CAP guideline selects more patients for anti-HER2 targeted therapy, mostly based on the modifications of criteria to evaluate ISH-HER2.
authors.affiliation: Department of Pathology, Ipatimup Diagnostics, Ipatimup, Porto, Portugal.|Faculty of Medicine, University of Porto, Porto, Portugal.
authors.forename: António
authors.initials: A
authors.lastname: Polónia
authors.affiliation: Department of Pathology, Ipatimup Diagnostics, Ipatimup, Porto, Portugal.|Faculty of Medicine, University of Porto, Porto, Portugal.
authors.forename: Dina
authors.initials: D
authors.lastname: Leitão
authors.affiliation: Department of Pathology, Ipatimup Diagnostics, Ipatimup, Porto, Portugal. fernando.schmitt@ipatimup.pt.|Faculty of Medicine, University of Porto, Porto, Portugal. fernando.schmitt@ipatimup.pt.|Laboratoire national de santé, 1, rue Louis Rech, L-3555, Dudelange, Luxembourg. fernando.schmitt@ipatimup.pt.
authors.forename: Fernando
authors.initials: F
authors.lastname: Schmitt
mesh_terms: D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000032:analysis* / Q000235:genetics; D001943:Breast Neoplasms / Q000145:classification* / Q000188:drug therapy / Q000235:genetics; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization / Q000379:methods*; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D017410:Practice Guidelines as Topic; D057285:Precision Medicine; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis* / Q000235:genetics; D000068878:Trastuzumab / Q000627:therapeutic use
chemical_list: D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab; C508053:ERBB2 protein, human
keywords: ASCO/CAP; Breast cancer; HER2; SISH