CD44H expression in reactive mesothelium, pleural mesothelioma and pulmonary adenocarcinoma

Our plain-English summary of CD44H expression in reactive mesothelium, pleural mesothelioma and pulmonary adenocarcinoma, by R.L. Attanoos, R. Webb, A.R. Gibbs (Histopathology, 1997).

The study

• Authors: R.L. Attanoos, R. Webb, A.R. Gibbs
• Journal: Histopathology
• Published: 1997;30(3):260-3
• Cited by: 40 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Malignant mesotheliomas are known to produce hyaluronic acid, in contrast to most pulmonary adenocarcinomas which produce neutral mucin. CD44H is the major cell surface receptor for hyaluronic acid. The aim of this study was to investigate immunohistochemically the expression of this antigen in reactive mesothelium, pleural mesothelioma and pulmonary adenocarcinoma and to assess its diagnostic utility in distinguishing the two tumours. Diffuse and intense membranous CD44H immunoreactivity was seen in 15 of 20 (75%) mesotheliomas and in all 20 biopsies of reactive mesothelium. In contrast, focal (< 10% tumour) expression of CD44H was seen in only three of 20 (15%) pulmonary adenocarcinomas. We advocate the use of CD44H as a positive mesothelial marker for incorporation alongside other established immunohistochemical markers used to distinguish mesothelioma from adenocarcinoma.

In plain English

This laboratory study tested whether staining tissue for CD44H, a cell-surface receptor for hyaluronic acid, could help pathologists tell pleural mesothelioma apart from lung adenocarcinoma. The authors stained stored tissue samples from Llandough Hospital, UK: 20 pleural mesotheliomas (11 epithelial, 6 biphasic, 3 sarcomatous), 20 lung adenocarcinomas, and 20 pleural biopsies showing reactive, non-cancerous overgrowth of mesothelial cells. The article does not report on asbestos exposure. All 20 reactive biopsies stained strongly and widely for CD44H. CD44H was found in 15 of 20 mesotheliomas, including 9 of 11 epithelial ones and the epithelial part of 5 of 6 biphasic ones. Staining in sarcomatous areas was mild and very patchy. Only 3 of 20 adenocarcinomas stained, and in each of these fewer than 10% of tumour cells were positive. The authors calculated that CD44H was 75% sensitive and 85% specific for mesothelioma. They warned that lymphocytes, macrophages and reactive lung cells also stain, which can lead to misreading. The authors concluded that CD44H, together with thrombomodulin, should be added to the standard panel of markers used to diagnose pleural mesothelioma.

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 (immunohistochemistry) study of archived tissue samples, assessing a diagnostic marker
• Who was studied: Paraffin-embedded surgical tissue from the histopathology files of Llandough Hospital (Penarth, UK). The samples were 20 pleural mesotheliomas (11 epithelial, 6 biphasic, 3 sarcomatous), 20 pulmonary adenocarcinomas, and 20 pleural biopsies showing reactive mesothelial hyperplasia. Dates of the cases were not given.
• Main results:
  • All 20 reactive mesothelium biopsies showed strong and diffuse CD44H expression.
  • CD44H expression was seen in 15 of 20 mesotheliomas (75%). Staining covered 10 to 50% of cells and was intense in 9 of 11 (82%) epithelial mesotheliomas and in the epithelial component of 5 of 6 (83%) biphasic mesotheliomas.
  • In sarcomatous tissue, CD44H was seen in 1 of 3 (33%) purely sarcomatous mesotheliomas and in the sarcomatous component of 1 of 6 (17%) biphasic tumours. In all sarcomatous areas the staining was mild and very focal.
  • CD44H was seen in only 3 of 20 (15%) pulmonary adenocarcinomas: two acinar and one bronchiolo-alveolar. In each, fewer than 10% of tumour cells stained.
  • Overall, the authors calculated CD44H to be 75% sensitive and 85% specific for mesothelioma.
  • In mucin staining, acid mucin was seen in 13 of 20 (65%) mesotheliomas. Among adenocarcinomas, 7 of 20 (35%) produced acid mucin and 18 of 20 (90%) produced neutral mucin. The authors found no apparent correlation between CD44H expression and acid mucin production.
  • Comparing with their own earlier study, the authors reported higher sensitivity for CD44H than for thrombomodulin (75% vs 52%) but lower specificity (85% vs 94%).
• The authors' conclusion: The authors advocated including CD44H with thrombomodulin, as two positive mesothelial markers, alongside the standard panel of antibodies used to diagnose pleural mesothelioma.
• Limitations the authors state:
  • The authors described interpretation of staining as potentially problematic. Lymphocytes, macrophages and reactive alveolar pneumocytes also express CD44H, so tumours with heavy lymphocyte reactions or surrounding obstructive pneumonitis need careful examination.
  • The authors stated that CD44H, like thrombomodulin, had little use in identifying sarcomatous mesotheliomas.

Topics

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

Medical terms in this study, explained in our Lexicon: Mesothelium, Pleural Mesothelioma, Adenocarcinoma, Malignant Mesothelioma, Hyaluronic Acid, Mesothelioma.

Related studies

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• Calretinin, thrombomodulin, CEA, and CD15: a useful combination of immunohistochemical markers for differentiating pleural epithelial mesothelioma from peripheral pulmonary adenocarcinoma — C.E. Comin, L. Novelli, et al. (2001)
• Ber-EP4 for differentiating adenocarcinoma from reactive and neoplastic mesothelial cells in serous effusions. Comparison with carcinoembryonic antigen, B72.3 and Leu-M1 — M.E. Bailey, R.W. Brown, et al. (1996)
• Cytological differential diagnosis among adenocarcinoma, epithelial mesothelioma, and reactive mesothelial cells in serous effusions by immunocytochemistry — X.Y. Su, G.D. Li, et al. (2011)
• Ribonucleotide reductase immunoreactivity in adenocarcinoma cells and malignant or reactive mesothelial cells in serous effusions — H. Okamura, T. Kamei, et al. (2003)
• Value of the mesothelium-associated antibodies thrombomodulin, cytokeratin 5/6, calretinin, and CD44H in distinguishing epithelioid pleural mesothelioma from adenocarcinoma metastatic to the pleura — P.M. Cury, D.N. Butcher, et al. (2000)

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