title: Comparison of HER2 status in primary and paired metastatic sites of gastric carcinoma.
abstract: BACKGROUND
  Trastuzumab has recently shown efficacy in the treatment of HER2-positive advanced gastric adenocarcinoma. Although antibody-based therapies target the metastatic disease, HER2 status is usually evaluated in the primary tumour because metastatic sites are rarely biopsied. The aim of this study was to compare HER2 status in primary and paired metastatic sites of gastric adenocarcinoma.
  
  
  METHODS
  The HER2 status was assessed by fluorescence in situ hybridisation (FISH) and immunohistochemistry (IHC) in 72 secondary lesions of gastric adenocarcinoma and in the corresponding primary tumours.
  
  
  RESULTS
  Concordance of FISH results, evaluable in 68 primary and matched metastatic sites, was 98.5%. Concordance of IHC results, available in 39 of the 72 paired cases, was 94.9%. Only one case showed discordance between primary tumour and metastasis, being negative by both IHC and FISH in the primary and showing HER2 overexpression and amplification in the corresponding pancreatic lymph node metastasis.
  
  
  CONCLUSIONS
  The high concordance observed between HER2 results obtained by both IHC and FISH on primary tumours and corresponding metastases suggests that in gastric cancer HER2 status is maintained in most cases unchanged during the metastatic process.
authors.affiliation: Medical Oncology Unit, Azienda Ospedaliero-Universitaria, Via Gramsci 14, Parma 43126, Italy. cbozzetti@ao.pr.it
authors.forename: C
authors.initials: C
authors.lastname: Bozzetti
authors.forename: F V
authors.initials: FV
authors.lastname: Negri
authors.forename: C A
authors.initials: CA
authors.lastname: Lagrasta
authors.forename: P
authors.initials: P
authors.lastname: Crafa
authors.forename: C
authors.initials: C
authors.lastname: Bassano
authors.forename: I
authors.initials: I
authors.lastname: Tamagnini
authors.forename: G
authors.initials: G
authors.lastname: Gardini
authors.forename: R
authors.initials: R
authors.lastname: Nizzoli
authors.forename: F
authors.initials: F
authors.lastname: Leonardi
authors.forename: D
authors.initials: D
authors.lastname: Gasparro
authors.forename: R
authors.initials: R
authors.lastname: Camisa
authors.forename: S
authors.initials: S
authors.lastname: Cavalli
authors.forename: S
authors.initials: S
authors.lastname: Capelli
authors.forename: E M
authors.initials: EM
authors.lastname: Silini
authors.forename: A
authors.initials: A
authors.lastname: Ardizzoni
mesh_terms: D000230:Adenocarcinoma / Q000737:chemistry* / Q000188:drug therapy / Q000473:pathology*; D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal / Q000627:therapeutic use; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents / Q000627:therapeutic use; D001202:Ascitic Fluid / Q000737:chemistry; D014408:Biomarkers, Tumor / Q000032:analysis*; D002986:Clinical Trials as Topic; D004943:Esophagogastric Junction; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008113:Liver Neoplasms / Q000737:chemistry / Q000556:secondary; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D010534:Peritoneal Neoplasms / Q000737:chemistry / Q000556:secondary; D016066:Pleural Effusion, Malignant / Q000737:chemistry; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis*; D012878:Skin Neoplasms / Q000737:chemistry / Q000556:secondary; D013274:Stomach Neoplasms / Q000737:chemistry* / Q000188:drug therapy / Q000473:pathology*; D000068878:Trastuzumab; D015854:Up-Regulation
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab; C508053:ERBB2 protein, human