title: HER2 gene amplification and protein expression in pancreatic ductal adenocarcinomas.
abstract: BACKGROUND
  Despite advances in combination therapies, the prognosis of pancreatic ductal adenocarcinoma (PDAC) remains extremely poor. Blocking of overexpressed HER2 oncogene improves survival in breast and gastroesophageal cancer and might be also a therapeutic option in PDAC. The purpose of this study was to evaluate HER2 gene amplification and protein expression in PDAC.
  
  
  METHODS
  HER2 protein expression was investigated using a FDA-approved antibody in 87 formalin-fixed and paraffin-embedded cases of PDAC with complete follow-up. HER2 gene amplification was assessed on tissue microarrays using dual color silver in situ hybridization (DISH).
  
  
  RESULTS
  Generally, HER2 immunostaining showed considerable heterogeneity. In 19 cases, ≥10 of tumor cells showed some positive reaction. In no case, complete membranous staining was observed. Using the scoring system developed for assessment of HER2 status in gastroesophageal cancer, 9 cases showed positive immunohistologic staining (score 2+ to 3+). After performing DISH, 6 (7%) immunohistochemically 2+ or 3+ cases were found to have HER2 gene amplification, whereas none of these cases showed polyploidy. No association of HER2 status and clinicopathologic parameters or survival was observed (P>0.05).
  
  
  CONCLUSIONS
  HER2 is overexpressed in a subset of PDACs, identifying them as possible candidates for a targeted therapy. For assessment of HER2 status in PDAC, the scoring system originally developed for gastric cancer is recommend.
authors.affiliation: *Clinical Institute of Pathology ‡Department of Surgery, Medical University of Vienna, Vienna †Pathologie and Zytodiagnostik, Schweygerstraße 7a, Hall in Tirol, Austria.
authors.forename: Klaus
authors.initials: K
authors.lastname: Aumayr
authors.forename: Afschin
authors.initials: A
authors.lastname: Soleiman
authors.forename: Klaus
authors.initials: K
authors.lastname: Sahora
authors.forename: Martin
authors.initials: M
authors.lastname: Schindl
authors.forename: Gregor
authors.initials: G
authors.lastname: Werba
authors.forename: Sebastian F
authors.initials: SF
authors.lastname: Schoppmann
authors.forename: Peter
authors.initials: P
authors.lastname: Birner
mesh_terms: D000368:Aged; D021441:Carcinoma, Pancreatic Ductal / Q000175:diagnosis* / Q000401:mortality; D005260:Female; D005784:Gene Amplification; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000175:diagnosis* / Q000401:mortality; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D012834:Silver; D016019:Survival Analysis; D046888:Tissue Array Analysis
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases; D012834:Silver; C508053:ERBB2 protein, human