HER-2 amplification is highly homogenous in gastric cancer

Hum Pathol. 2009 Jun;40(6):769-77. doi: 10.1016/j.humpath.2008.11.014. Epub 2009 Mar 9.

Abstract

Her-2 is the molecular target for antibody-based treatment of breast cancer (trastuzumab). The potential benefit of anti-Her-2 therapy is currently investigated in several other HER-2-amplified cancers including gastric cancer. Although HER-2 amplification occurs in more than 10% of gastric cancers, potential heterogeneity of HER-2 amplification and overexpression could represent a major drawback for anti-Her-2 therapy. To address the potential applicability of trastuzumab in gastric cancer, tissue microarray sections of 166 gastric adenocarcinomas and 69 lymph node metastases were analyzed for Her-2 overexpression and amplification using Food and Drug Administration-approved reagents for immunohistochemistry and fluorescence in situ hybridization. HER-2 amplification was seen in 27 (16%) of 166 gastric adenocarcinomas. Amplification was typically high level with more than 20 HER-2 copies per tumor cell and a HER-2/centromere 17 ratio >3. Amplification was associated with intestinal tumor phenotype but unrelated to survival, grading, pT, pN, or pM. Identical HER-2 status was found in primary tumor and their matched lymph node metastases. Moreover, HER-2 and Topoisomerase IIalpha coamplification analysis of 3 to 16 large sections from 8 Her-2-positive gastric cancers did not reveal any heterogeneity of the amplicon site. The high level of HER-2 amplification in combination with the homogeneity of its expression in primary and metastatic tumors argues for a possible therapeutic utility of trastuzumab in HER-2-amplified gastric adenocarcinomas.

MeSH terms

  • Adenocarcinoma / genetics*
  • Adult
  • Aged
  • Aged, 80 and over
  • Antibodies, Monoclonal / therapeutic use
  • Antibodies, Monoclonal, Humanized
  • Antigens, Neoplasm / genetics
  • DNA Topoisomerases, Type II / genetics
  • DNA-Binding Proteins / genetics
  • Female
  • Gene Amplification
  • Genes, erbB-2 / genetics*
  • Humans
  • In Situ Hybridization, Fluorescence
  • Lymphatic Metastasis
  • Male
  • Middle Aged
  • Receptor, ErbB-2 / immunology
  • Stomach Neoplasms / drug therapy
  • Stomach Neoplasms / genetics*
  • Stomach Neoplasms / pathology
  • Tissue Array Analysis
  • Trastuzumab

Substances

  • Antibodies, Monoclonal
  • Antibodies, Monoclonal, Humanized
  • Antigens, Neoplasm
  • DNA-Binding Proteins
  • ERBB2 protein, human
  • Receptor, ErbB-2
  • DNA Topoisomerases, Type II
  • Trastuzumab