title: Malignant mesothelioma does not demonstrate overexpression or gene amplification despite cytoplasmic immunohistochemical staining for c-Erb-B2.
abstract: BACKGROUND
  Previous studies have shown conflicting results regarding the expression of c-Erb-B2 in malignant mesothelioma. Overexpression of the c-erb-B2 gene product in a subset of mesothelioma may have prognostic or therapeutic implications.
  
  
  OBJECTIVE
  To determine whether malignant mesothelioma demonstrates c-Erb-B2 overexpression and, if so, whether such overexpression correlates with gene amplification.
  
  
  METHODS
  Immunohistochemistry, reverse transcription-polymerase chain reaction, and fluorescent in situ hybridization were used to analyze archived tissue from 37 cases of malignant mesothelioma.
  
  
  RESULTS
  Although immunohistochemical staining for c-Erb-B2 was detected in most mesotheliomas, the staining was cytoplasmic and was not consistent between the 2 different primary antibodies used. Moreover, even cases with strong cytoplasmic staining for c-Erb-B2 did not demonstrate increased messenger RNA levels or gene copy numbers compared to cases that demonstrated no staining.
  
  
  CONCLUSIONS
  Cytoplasmic immunoreactivity for c-Erb-B2 in mesothelioma does not represent gene overexpression or amplification and may be an immunohistochemical artifact.
authors.affiliation: Department of Pathology, University of California, San Francisco 94143, USA.
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Horvai
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.forename: Zhidong
authors.initials: Z
authors.lastname: Xu
authors.forename: Miranda J
authors.initials: MJ
authors.lastname: Kramer
authors.forename: David M
authors.initials: DM
authors.lastname: Jablons
authors.forename: Patrick A
authors.initials: PA
authors.lastname: Treseler
mesh_terms: D000911:Antibodies, Monoclonal / Q000378:metabolism; D061067:Antibodies, Monoclonal, Humanized; D016477:Artifacts; D003593:Cytoplasm / Q000737:chemistry* / Q000473:pathology; D005784:Gene Amplification / Q000235:genetics*; D018628:Gene Dosage; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics*; D018734:Genes, erbB-2 / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D008654:Mesothelioma / Q000737:chemistry / Q000235:genetics* / Q000473:pathology; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis* / Q000276:immunology; D012189:Retrospective Studies; D013194:Staining and Labeling; D000068878:Trastuzumab
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab