Value of thrombomodulin immunostaining in the diagnosis of mesothelioma

Our plain-English summary of Value of thrombomodulin immunostaining in the diagnosis of mesothelioma, by N.G. Ordóñez (Histopathology, 1997).

The study

• Author: N.G. Ordóñez
• Journal: Histopathology
• Published: 1997;31(1):25-30
• Cited by: 60 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Aims: Even with the benefit of immunohistochemistry and electron microscopy, the differential diagnosis between epithelial mesothelioma and pulmonary adenocarcinoma is often difficult. In most instances, the diagnosis of mesothelioma must be reached by the use of immunohistochemical markers that react with adenocarcinomas, but not with mesotheliomas. The purpose of this study is to determine the value of thrombomodulin (TM) as a positive marker for mesothelioma when distinguishing epithelial pleural mesothelioma from pulmonary adenocarcinoma.

Methods And Results: TM was expressed in 28 (80%) of 35 epithelial pleural mesotheliomas, but only five (10.9%) of 46 pulmonary adenocarcinomas had appreciable reactivity for this marker.

Conclusion: It is concluded that TM can be useful in separating pulmonary adenocarcinoma from epithelial mesothelioma, but it should be used only in conjunction with other immunohistochemical markers that are currently employed in distinguishing between these two types of malignancies.

In plain English

This study, by a single author at The University of Texas M.D. Anderson Cancer Center, tested whether a laboratory stain for the protein thrombomodulin could help pathologists tell epithelial pleural mesothelioma apart from lung adenocarcinoma, two cancers that can be hard to distinguish. Stored tissue from 42 pleural mesotheliomas and 106 primary lung carcinomas was stained. Thrombomodulin was found in 28 (80%) of 35 epithelial pleural mesotheliomas, mainly along the cell membrane. It was found in 7 (15.2%) of 46 lung adenocarcinomas; two of those seven showed only trace staining, leaving five (10.9%) with significant staining. It was also found in 21 (77.7%) of 27 squamous cell lung carcinomas. Spindle cell tissue stained only focally, in one of four mixed tumours and one of three spindle cell mesotheliomas. The author concluded that the stain can assist in this distinction. Because 20% of the epithelial mesotheliomas were negative and about 15% of the adenocarcinomas stained, the author said it should always be used together with other markers. The article does not discuss 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 diagnostic study: immunohistochemical staining for thrombomodulin of archived tumour tissue
• Who was studied: Tissue from the pathology files of The University of Texas M.D. Anderson Cancer Center, Houston. There were 42 pleural mesotheliomas (35 epithelial, 4 biphasic, 3 spindle cell) and 106 primary lung carcinomas, including 46 adenocarcinomas and 27 squamous cell carcinomas. Dates of the cases are not given.
• Exposure: Not applicable. This was a diagnostic tissue-staining study, and the article does not discuss asbestos or any other exposure.
• Main results:
  • Epithelial pleural mesotheliomas: 28 (80%) of 35 stained for thrombomodulin along the cell membrane.
  • Mixed (biphasic) mesotheliomas: the epithelial component stained in 3 of 4 tumours.
  • Spindle cell tissue: focal (1+) staining in the spindle cell component of one mixed tumour and in 1 of 3 spindle cell mesotheliomas.
  • Lung adenocarcinomas: 7 (15.2%) of 46 stained for thrombomodulin.
  • Lung adenocarcinomas: only 5 (10.9%) of the 46 showed significant staining. The other two positive tumours showed only trace staining.
  • Squamous cell lung carcinomas: 21 (77.7%) of 27 stained for thrombomodulin.
  • Adenosquamous carcinomas: both stained in their squamous areas but not in their adenocarcinoma areas.
  • Other lung tumours: no staining in carcinoid tumours (0/16), large cell (0/6), small cell (0/8) or spindle cell (0/1) lung carcinomas.
  • Antigen retrieval methods did not enhance the staining.
  • All epithelial mesotheliomas showed a membranous staining pattern, but none showed the 'spiky' appearance previously described in fluid cytology specimens.
• The authors' conclusion: The author concluded that, although thrombomodulin is not specific for mesothelioma, staining for it can assist in distinguishing epithelial mesothelioma from lung adenocarcinoma, especially when a positive marker for mesothelioma is needed. The author also said it should always be used with other markers.
• Limitations the authors state:
  • Limited sensitivity and specificity: 20% of epithelial mesotheliomas were negative and about 15% of lung adenocarcinomas stained. For this reason the author said the stain should always be used with other markers.
  • Too few spindle cell mesotheliomas were studied to reach a definite conclusion about the stain's value for that type.

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: Mesothelioma, Immunohistochemistry, Differential Diagnosis, Adenocarcinoma, Pleural Mesothelioma.

Related studies

• Thrombomodulin expression in transitional cell carcinoma — N.G. Ordóñez (1998)
• Expression of calretinin, thrombomodulin, keratin 5, and mesothelin in lung carcinomas of different types: an immunohistochemical analysis of 596 tumors in comparison with epithelioid mesotheliomas of the pleura — M. Miettinen, M. Sarlomo-Rikala (2003)
• Expression of thrombomodulin, calretinin, cytokeratin 5/6, D2-40 and WT-1 in a series of primary carcinomas of the lung: an immunohistochemical study in comparison with epithelioid pleural mesothelioma — C.E. Comin, L. Novelli, et al. (2014)
• Value of claudin-4 immunostaining in the diagnosis of mesothelioma — N.G. Ordóñez (2013)
• Value of PAX8, PAX2, claudin-4, and h-caldesmon immunostaining in distinguishing peritoneal epithelioid mesotheliomas from serous carcinomas — N.G. Ordóñez (2013)
• 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)

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