title: Evaluation of HER-2/neu overexpression in gastric carcinoma using a tissue microarray.
abstract: BACKGROUND
  Amplification and overexpression of human epidermal growth factor receptor 2 (HER2 / neu) oncogene has considerable prognostic value in breast and gastric cancers. This study aimed to evaluate the frequency, overexpression pattern, clinical significance, and concordance between the results for protein expression and gene amplification of HER-2/neu in gastric and gastro-esophageal junction carcinomas.
  
  
  METHODS
  In this study, 101 gastric tissue samples which were included in tissue microarray were immunohistochemically examined for overexpression of HER2/neu. Chromogenic in situ hybridization (CISH) was used for HER-2/neu amplification. The correlation of HER2/neu amplification with clinicopathological parameters was also assessed. In addition, concordance between CISH and IHC was detected.
  
  
  RESULTS
  This study demonstrated a significant difference in the overexpression of HER2/neu in gastric tumors. The overexpression of HER2/neu was significantly higher in intestinal type, poorly differentiated grade, large size (5 cm≤) and positive nodal involvement tumors (p-value=0.041, 0.015, 0.038 and 0.071, respectively). Also, amplification of HER2/neu according to CISH test, had a significant positive correlation with tumor size and tumor type (p-value=0.018 and 0.058, respectively).Concordance between CISH and IHC was 76.9% in 101 evaluable samples.
  
  
  CONCLUSIONS
  IHC/CISH differences were attributed to basolateral membranous immunoreactivity of glandular cells resulting in incomplete membranous reactivity and/or a higher rate of tumor heterogeneity in gastric cancers compared to breast cancers. Therefore, this can be a potential marker for targeted therapy of malignant gastric tumors.
authors.affiliation: Department of Pathology, Firoozgar Hospital, School of Medicine, Iran University of Medical Sciences, Tehran, Iran E-mail mitmehr@yahoo.com.
authors.forename: Nasser
authors.initials: N
authors.lastname: Rakhshani
authors.forename: Elham
authors.initials: E
authors.lastname: Kalantari
authors.forename: Hadi
authors.initials: H
authors.lastname: Bakhti
authors.forename: Masoud Reza
authors.initials: MR
authors.lastname: Sohrabi
authors.forename: Mitra
authors.initials: M
authors.lastname: Mehrazma
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005500:Follow-Up Studies; D005784:Gene Amplification; D006801:Humans; D007124:Immunoenzyme Techniques; D017403:In Situ Hybridization; D007414:Intestinal Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D046888:Tissue Array Analysis
chemical_list: D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human