title: HER2 amplification in gastric cancer is a rare event restricted to the intestinal phenotype.
abstract: The objectives of this study were to identify HER2 prevalence in gastric cancer and correlate it with location, phenotype, and follow-up. Consecutive gastric cancer patients with tissue blocks, gross data, and follow-up data, were submitted to immunohistochemistry (IHC) with HercepTest. Chromogenic and fluorescence in situ hybridization was performed in IHC-positive tumors. A total of 269 patients were included with a median age of 61 years. In 172 gastrectomized patients, histotypes were diffuse (72, 41.8%), intestinal (63, 36.6%), and mixed (37, 21.5%). HER2 IHC expression was 0 in 167, 2+ in 2, and 3+ in 3 tumors. Only endoscopic biopsies were available in 97 patients and HER2 IHC expression was 0 in 88, 1+ in 3, 2+ in 4, and 3+ in 2 patients. In all, 10/269 (3.7%) had HER2 amplification. Amplified tumors were intestinal adenocarcinomas located throughout the different regions of the stomach. Heterogeneity was documented in 4 widely sampled tumors. HER2 amplification was restricted to the intestinal phenotype. It is a rare event and its screening should be driven by gastric cancer histotype.
authors.affiliation: Departamento de Patología, National Institute of Medical Sciences and Nutrition Salvador Zubiran, Mexico City, Mexico.
authors.forename: Carolina
authors.initials: C
authors.lastname: Cruz-Reyes
authors.forename: Armando
authors.initials: A
authors.lastname: Gamboa-Dominguez
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D004273:DNA, Neoplasm / Q000235:genetics*; D005260:Female; D005500:Follow-Up Studies; D005743:Gastrectomy; D005784:Gene Amplification / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D015995:Prevalence; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics* / Q000378:metabolism; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*
chemical_list: D004273:DNA, Neoplasm; D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human
keywords: HER2; Mexico; amplification; gastric cancer; intestinal phenotype; prevalence