title: HER2 expression and its clinicopathological features in resectable gastric cancer.
abstract: BACKGROUND
  A recent randomized controlled trial (Trastuzumab for Gastric Cancer [ToGA] study) established standard scoring criteria of human epidermal growth factor receptor 2 (HER2) for gastric cancer and demonstrated the efficacy of trastuzumab for treating metastatic gastric cancer. The aim of the present study was to evaluate the frequency of HER2-positive cases by application of the standard criteria in patients with resectable gastric cancer and to examine the relationships between HER2 expression and prognosis, mucin phenotype, p53 status, and clinicopathological features.
  
  
  METHODS
  A total of 213 patients were included in this retrospective study. All tumor samples were examined for HER2 expression by immunohistochemistry (IHC), HER2 amplification by in situ hybridization, and mucin and p53 expression by staining for CD10, MUC2, MUC5AC, MUC6, and p53.
  
  
  RESULTS
  HER2-positive tumors were identified in 25 patients (11.7 %). HER2-positive cases were more frequently found in men, older patients, and in the intestinal histological type (P = 0.0048, 0.0309, and <0.0001, respectively). Although no association was found between HER2 overexpression and mucin phenotype, the expression of CD10 and p53 was significantly correlated with HER2 positivity (P = 0.0079 and 0.013). The overall survival of HER2-negative and -positive patients was not significantly different. However, in patients with stage III/IV, overall survival was worse in HER2-positive patients (P = 0.0149). In a comparison between dual-color in situ hybridization (DISH) and fluorescence in situ hybridization (FISH), four IHC2+/3+ cases that were DISH-positive were judged as negative by FISH.
  
  
  CONCLUSIONS
  Our study indicated that HER2 expression was less frequent in resectable gastric cancer than in metastatic gastric cancer. The impact of HER2 expression on survival was limited. DISH was superior to FISH for evaluating cases with limited HER2 expression.
authors.affiliation: Department of Surgery, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawahara-Cho, Sakyo-ku, Kyoto, 606-8507, Japan.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Kataoka
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Okabe
authors.forename: Akihiko
authors.initials: A
authors.lastname: Yoshizawa
authors.forename: Sachiko
authors.initials: S
authors.lastname: Minamiguchi
authors.forename: Kenichi
authors.initials: K
authors.lastname: Yoshimura
authors.forename: Hironori
authors.initials: H
authors.lastname: Haga
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Sakai
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D017403:In Situ Hybridization / Q000379:methods*; D017404:In Situ Hybridization, Fluorescence / Q000379:methods; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D015260:Neprilysin / Q000235:genetics; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics*; D012189:Retrospective Studies; D012737:Sex Factors; D013274:Stomach Neoplasms / Q000235:genetics / Q000473:pathology* / Q000601:surgery; D015996:Survival Rate; D016159:Tumor Suppressor Protein p53 / Q000235:genetics
chemical_list: D015260:Neprilysin; D018719:Erb-b2 Receptor Tyrosine Kinases; D016159:Tumor Suppressor Protein p53; C508053:ERBB2 protein, human