title: Targeted next-generation sequencing enables reliable detection of HER2 (ERBB2) status in breast cancer and provides ancillary information of clinical relevance.
abstract: HER2-positive breast cancers are a heterogeneous group of tumors, which share amplification and overexpression of HER2. In routine diagnostics, the HER2 (ERBB2) status is currently assessed by immunohistochemistry (IHC) and in situ hybridization (ISH). Data on targeted next-generation sequencing (NGS) approaches that could be used to determine the HER2 status are sparse. Employing two breast cancer-related gene panels, we performed targeted NGS of 41 FFPE breast cancers for which full pathological work-up including ISH and IHC results was available. Selected cases were analyzed by qPCR. Of the 41 cases, the HER2 status of the 4 HER2-positive and 6 HER2-negative tumors was independently detected by our NGS approach achieving a concordance rate of 100%. The remaining 31 cases were equivocal HER2 cases by IHC of which 5 showed amplification of HER2 by ISH. Our NGS approach classified all non-amplified cases correctly as HER2 negative and corroborated all but one of the 5 cases with amplified HER2 as detected by ISH. For the overall cohort, concordance between the gold standard and NGS was 97.6% (sensitivity 88.9% and specificity 100%). Additionally, we observed mutations in PIK3CA (44%), HER2 (8%), and CDH1 (6%) among others. Amplifications were found in CCND1 (12%), followed by MYC (10%) and EGFR (2%) and deletions in CDKN2A (10%), MAP2K4 and PIK3R1 (2% each). We here show that targeted NGS data can be used to interrogate the HER2 status with high specificity and high concordance with gold standard methods. Moreover, this approach identifies additional genetic events that may be clinically exploitable. © 2016 Wiley Periodicals, Inc.
authors: Institute of Pathology University Hospital Heidelberg, Heidelberg, Germany.|Institute of Pathology Technical University Munich (TUM), Munich, Germany.
authors: Nicole
authors: N
authors: Pfarr
authors: Institute of Pathology University Hospital Heidelberg, Heidelberg, Germany.
authors: Roland
authors: R
authors: Penzel
authors: Institute of Pathology University Hospital Heidelberg, Heidelberg, Germany.
authors: Volker
authors: V
authors: Endris
authors: Institute of Pathology University Hospital Heidelberg, Heidelberg, Germany.
authors: Clemens
authors: C
authors: Lier
authors: Institute of Pathology University Hospital Heidelberg, Heidelberg, Germany.
authors: Christa
authors: C
authors: Flechtenmacher
authors: Institute of Pathology University Hospital Heidelberg, Heidelberg, Germany.
authors: Anna-Lena
authors: AL
authors: Volckmar
authors: Institute of Pathology University Hospital Heidelberg, Heidelberg, Germany.
authors: Martina
authors: M
authors: Kirchner
authors: Institute of Pathology Charité University Hospital, Berlin, Germany.
authors: Jan
authors: J
authors: Budczies
authors: Institute of Pathology University Hospital Heidelberg, Heidelberg, Germany.
authors: Jonas
authors: J
authors: Leichsenring
authors: Institute of Pathology University Hospital Heidelberg, Heidelberg, Germany.|Tissue Bank of the National Center for Tumor Diseases (NCT), Heidelberg, Germany.
authors: Esther
authors: E
authors: Herpel
authors: Institute of Pathology Technical University Munich (TUM), Munich, Germany.
authors: Aurelia
authors: A
authors: Noske
authors: Institute of Pathology Technical University Munich (TUM), Munich, Germany.|German Cancer Consortium (DKTK), Germany.
authors: Wilko
authors: W
authors: Weichert
authors: German Cancer Consortium (DKTK), Germany.|National Center for Tumor Diseases University Hospital, Heidelberg, Germany.
authors: Andreas
authors: A
authors: Schneeweiss
authors: Institute of Pathology University Hospital Heidelberg, Heidelberg, Germany.|German Cancer Consortium (DKTK), Germany.
authors: Peter
authors: P
authors: Schirmacher
authors: Institute of Pathology University Hospital Heidelberg, Heidelberg, Germany.|German Cancer Consortium (DKTK), Germany.
authors: Hans-Peter
authors: HP
authors: Sinn
authors: Institute of Pathology University Hospital Heidelberg, Heidelberg, Germany.|German Cancer Consortium (DKTK), Germany.
authors: Albrecht
authors: A
authors: Stenzinger
mesh_terms: D014408:Biomarkers, Tumor / Q000235:genetics*; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D005260:Female; D005784:Gene Amplification; D059014:High-Throughput Nucleotide Sequencing / Q000379:methods*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D009154:Mutation / Q000235:genetics*; D009367:Neoplasm Staging; 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