A comparison of epidermal growth factor receptor expression in malignant peritoneal and pleural mesothelioma

Our plain-English summary of A comparison of epidermal growth factor receptor expression in malignant peritoneal and pleural mesothelioma, by Y. Enomoto, T. Kasai, M. Takeda, et al (Pathology International, 2012).

The study

• Authors: Y. Enomoto, T. Kasai, M. Takeda, M. Takano, K. Morita, E. Kadota, N. Iizuka, H. Maruyama, J. Haratake, Y. Kojima, N. Ikeda, A. Nonomura
• Journal: Pathology International
• Published: 2012;62(4):226-31
• Cited by: 11 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

An evaluation of epidermal growth factor receptor (EGFR) phenotypic expression in malignant pleural and peritoneal mesothelioma was undertaken, using immunohistochemical (IHC) and fluorescence in situ hybridization (FISH) analysis. Thirty-eight malignant mesothelioma (MM) specimens were subjected to IHC staining and FISH to evaluate the expression of EGFR protein and gene status. Overall positive IHC reaction was detected in 20/38 (53%) cases, in 11/22 (50%) pleural MM, and in 9/16 (56%) peritoneal MM. Our study confirmed that EGFR membranous expression is a common feature in MM, but not in benign mesothelial lesion. Thirty-seven cases did not show a gene copy number gain. Only one case showed a copy number gain. The protein overexpression of EGFR was not related to a gene copy number gain.

© 2012 The Authors. Pathology International © 2012 Japanese Society of Pathology and Blackwell Publishing Asia Pty Ltd.

In plain English

This was a laboratory study of archived tumor tissue from 38 Japanese patients with malignant mesothelioma: 22 pleural and 16 peritoneal. The authors measured a cell-surface protein called epidermal growth factor receptor (EGFR) by tissue staining. They also counted copies of the EGFR gene using a fluorescence technique (FISH). A tumor counted as EGFR-positive only at the highest staining score (3+). Some EGFR staining appeared in 37 of 38 tumors, and 20 of 38 (53%) were positive. That was 11 of 22 (50%) pleural and 9 of 16 (56%) peritoneal tumors, a difference the authors found not significant. Positivity was more common in epithelioid than non-epithelioid tumors (67% vs. 21%). Benign mesothelial lesions and pleuritis (inflamed pleura) showed EGFR inside cells but none on the cell membrane. Only one tumor showed a gain in EGFR gene copies. Protein level was not significantly related to gene copy gain. The authors concluded that EGFR overexpression is common in mesothelioma, especially the epithelial subtype. The article did not report the patients' asbestos exposure.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Laboratory (pathology) study of archived tumor tissue using immunohistochemistry (protein staining) and fluorescence in situ hybridization (gene copy counting)
• Who was studied: 38 cases of malignant mesothelioma (22 pleural, 16 peritoneal; median age 63, range 41 to 81) from the archives of five hospital or university pathology departments in Japan. Benign mesothelial lesions and pleuritis cases were examined for comparison.
• Exposure: Not reported: the study measured EGFR protein and gene copy number in tumor tissue and gives no information on the patients' asbestos exposure
• Main results:
  • Method definition: a tumor was counted as EGFR-positive only if it scored 3+, meaning strong staining in more than 50% of cells
  • All 38 mesotheliomas: some EGFR staining in 37 of 38 (97%); EGFR-positive (3+) in 20 of 38 (53%)
  • By site: EGFR-positive in 11 of 22 (50%) pleural and 9 of 16 (56%) peritoneal mesotheliomas
  • The authors found no significant difference in EGFR positivity between pleural and peritoneal mesothelioma
  • EGFR positivity was more common in epithelioid than in non-epithelioid mesothelioma (67% vs. 21%), P less than 0.01
  • Benign mesothelial lesions and pleuritis cases showed EGFR in the cell interior (cytoplasm) but no membranous staining; the difference from mesothelioma was statistically significant (P less than 0.01)
  • EGFR gene copy number in the 38 mesotheliomas: normal two-copy pattern (disomy) in 29/38 (76%), low polysomy in 8/38 (21%), and copy number gain (high polysomy) in only one case
  • No significant correlation between EGFR protein expression and EGFR gene copy number gain in the mesotheliomas
  • All benign mesothelial lesions and pleuritis cases showed a disomic pattern with no gene copy number gain
• The authors' conclusion: The authors concluded that EGFR overexpression is a common feature of malignant mesothelioma, especially the epithelial subtype, and that it was not related to EGFR gene copy number gain
• Limitations the authors state:
  • The authors did not examine whether EGFR expression is linked to survival and said they would do so in the future
  • The authors said further and larger studies, including EGFR mutation analysis, are needed

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma, Peritoneal mesothelioma.

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, EGFR, Peritoneal Mesothelioma, Fluorescence In Situ Hybridization (FISH), Malignant Mesothelioma.

Related studies

• Epidermal growth factor receptor mutations in malignant pleural and peritoneal mesothelioma — Y. Enomoto, T. Kasai, et al. (2012)
• Patients with peritoneal mesothelioma lack epidermal growth factor receptor tyrosine kinase mutations that would make them sensitive to tyrosine kinase inhibitors — N. Kalra, A. Ashai, et al. (2012)
• Epidermal growth factor receptor overexpression in malignant pleural mesothelioma: prognostic correlations — O. Rena, L.R. Boldorini, et al. (2011)
• Increased expression of epidermal growth factor receptor in rat pleural mesothelial cells correlates with carcinogenicity of mineral fibres — S.P. Faux, C.E. Houghton, et al. (2000)
• Malignant pleural mesothelioma and epidermal growth factor receptor (EGF-R). Relationship of EGF-R with histology and survival using fixed paraffin embedded tissue and the F4, monoclonal antibody — H. Dazzi, P.S. Hasleton, et al. (1990)
• Increased epidermal growth factor-receptor protein in a human mesothelial cell line in response to long asbestos fibers — J.C. Pache, Y.M. Janssen, et al. (1998)

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