Malignant mesothelioma does not demonstrate overexpression or gene amplification despite cytoplasmic immunohistochemical staining for c-Erb-B2.
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.
Horvai
Andrew E
AE
Department of Pathology, University of California, San Francisco 94143, USA.
Li
Li
L
Xu
Zhidong
Z
Kramer
Miranda J
MJ
Jablons
David M
DM
Treseler
Patrick A
PA
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
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab