title: [Intratumoral heterogeneity of HER2 status in breast carcinoma].
abstract: Intratumoral heterogeneity of HER2 protein expression and HER2 gene amplification can negatively affect determination of HER2 status in a subset of invasive breast carcinomas. The frequency and clinical significance of HER2 genetic heterogeneity are unknown due to the lack of uniform criteria for diagnosis. Recent ASCO/CAP guidelines (2009) define HER2 genetic heterogeneity as the presence of between 5% and 50% of tumor cells with a HER2/CEP17 ratio >2.2. We describe a tool (a customized Excel spreadsheet) for easy and reproducible diagnosis of HER2 genetic heterogeneity according to ASCO/CAP criteria. Our tool may be useful for routine HER2 diagnostics and for studies to analyse the hitherto unknown predictive significance of HER2 genetic heterogeneity.
authors.affiliation: Institut für Pathologie, Kantonsspital St. Gallen, St. Gallen, Schweiz.
authors.forename: C
authors.initials: C
authors.lastname: Ohlschlegel
authors.forename: K
authors.initials: K
authors.lastname: Zahel
authors.forename: D
authors.initials: D
authors.lastname: Kradolfer
authors.forename: M
authors.initials: M
authors.lastname: Hell
authors.forename: W
authors.initials: W
authors.lastname: Jochum
mesh_terms: D014408:Biomarkers, Tumor / Q000235:genetics*; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology*; D002886:Chromosomes, Human, Pair 17 / Q000235:genetics; D005260:Female; D005784:Gene Amplification / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics; D018740:Genetic Heterogeneity; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods; D009361:Neoplasm Invasiveness / Q000235:genetics / Q000473:pathology; D017410:Practice Guidelines as Topic; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics*
chemical_list: D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human