title: Her-2/neu assessment for gastric carcinoma: validation of scoring system.
abstract: OBJECTIVE
  Gastric cancer is the second leading cause of cancer mortality in the world. Amplification of HER-2/neu oncogene has become an important biomarker for identifying patients who respond to HER-2 targeting therapy. A number of studies have analyzed HER-2/neu overexpression in gastric carcinoma, and the rate of HER2 positivity is variable, ranging from 6% to 35%.
  
  
  METHODS
  In our study HER-2/neu expression was assessed on 73 samples of primary gastric cancer, using immunohistochemistry. For 19 patients preoperative biopsy samples and resected specimens were available. Additionally, internal ring study was performed to estimate intraobserver variability of IHC scoring among pathologists at our department.
  
  
  RESULTS
  HER-2/neu overexpression was found in 10 (13.6%) of the tested samples, and it was more common in intestinal (22.5%) than the diffuse type (3.7%). Not one of the 6 analyzed mixed type tumors showed HER-2/neu expression. For the paired samples (preoperative biopsy samples and resected specimens) the concordance rate for HER-2/neu expression was 94.7%.
  
  
  CONCLUSIONS
  According to high concordance rate in paired samples we consider it appropriate to evaluate HER2 expression on biopsy specimens, especially in unresectable cases, and to re-evaluate it on resected specimens if available, due to high heterogeneity of a gastric cancer.
authors.affiliation: Department of Pathology, University of Split, School of Medicine, Croatia. ivana.mrklic@mefst.hr
authors.forename: Ivana
authors.initials: I
authors.lastname: Mrklic
authors.forename: Antonia
authors.initials: A
authors.lastname: Bendic
authors.forename: Nenad
authors.initials: N
authors.lastname: Kunac
authors.forename: Josko
authors.initials: J
authors.lastname: Bezic
authors.forename: Gea
authors.initials: G
authors.lastname: Forempoher
authors.forename: Merica Glavina
authors.initials: MG
authors.lastname: Durdov
authors.forename: Ivana
authors.initials: I
authors.lastname: Karaman
authors.forename: Ivana Kuzmic
authors.initials: IK
authors.lastname: Prusac
authors.forename: Valdi Pesutic
authors.initials: VP
authors.lastname: Pisac
authors.forename: Katarina
authors.initials: K
authors.lastname: Vilovic
authors.forename: Snjezana
authors.initials: S
authors.lastname: Tomic
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis* / Q000235:genetics; D001706:Biopsy; D002277:Carcinoma / Q000737:chemistry / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D017523:Croatia; D005784:Gene Amplification; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D015588:Observer Variation; D011237:Predictive Value of Tests; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis* / Q000235:genetics; D015203:Reproducibility of Results; D013274:Stomach Neoplasms / Q000737:chemistry / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D015854:Up-Regulation
chemical_list: D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human