Malignant mesothelioma: current status of histopathologic diagnosis and molecular profile

Our plain-English summary of Malignant mesothelioma: current status of histopathologic diagnosis and molecular profile, by S. Suster, C. Moran (Expert Review of Molecular Diagnostics, 2005).

The study

• Authors: S. Suster, C. Moran
• Journal: Expert Review of Molecular Diagnostics
• Published: 2005;5(5):715-23
• Type of article: Review
• Cited by: 7 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Malignant mesothelioma of the pleura is a relatively rare neoplasm that has been estimated to account for 20 deaths per million males per year in North America and Europe. A causative association has been well established with asbestos exposure. Paradoxically, the incidence of this tumor continues to rise despite public efforts to reduce, contain or eliminate exposure to asbestos fibers over the past few decades. Another paradoxical feature of the disease is that the majority of malignant mesotheliomas represent morphologically low-grade, well-differentiated neoplasms, yet they follow a relentlessly aggressive and virtually uniformly fatal outcome. For this reason, identification of clinical, morphologic, immunohistochemical or molecular genetic parameters is of extremely limited value for prognostication. Surprisingly, for a disease that currently has no known cure, one of the major problems still lies in establishing the correct diagnosis. Diagnosis acquires a particular relevance in light of the medicolegal ramifications of this disease, and diagnosis of malignant mesothelioma is still fraught with difficulties. Despite the advances in modern diagnostic techniques, no specific markers or morphologic features exist that are exclusive to these tumors. Herein, the current status of malignant mesothelioma diagnosis is reviewed, including the possible contributions of modern molecular techniques for their diagnosis.

In plain English

This article was a narrative review, not a new study, of how malignant mesothelioma, mainly of the pleura, was diagnosed in tissue samples and what molecular research had added as of 2005. The authors described three main tissue types: epithelioid, sarcomatoid (spindle cell) and biphasic. In their experience, epithelioid tumors made up approximately 80% of pleural cases. They wrote that a history of asbestos exposure can be difficult to define or prove. Citing earlier work, they noted that as many as 50% of new cases may lack a documented exposure history. They wrote that the sarcomatoid diagnosis had most likely been much abused in the past. No antibody stain was truly specific for mesothelioma, so panels of markers were used, and stains could not reliably separate reactive from malignant cells. Electron microscopy remained the gold standard for well-differentiated epithelioid tumors. They called the role of the SV40 virus in causing mesothelioma still debatable. The authors concluded that molecular findings had very limited diagnostic use so far and that diagnosis depended on a multidisciplinary approach.

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: Narrative review of the histopathologic diagnosis and molecular profile of malignant mesothelioma
• Who was studied: No patients were studied. The review covered published literature on diagnosing malignant mesothelioma, mainly pleural, with some reference to the authors' own experience.
• Exposure: Asbestos exposure was discussed as part of the clinical history used in diagnosis. The authors noted variability in length of exposure, type of exposure and fiber type (amphibole vs. chrysotile). Exposure was not measured in this article.
• Main results:
  • In the authors' experience, epithelioid malignant mesothelioma accounted for approximately 80% of cases of pleural malignant mesothelioma.
  • The authors stated that asbestos exposure can often be difficult to define or prove, and that a history of exposure is not sufficiently reliable or specific for diagnosing mesothelioma.
  • Citing earlier literature (not this article's own data), the authors noted that as many as 50% of newly diagnosed cases may not have a documented history of asbestos exposure.
  • The authors wrote that the diagnosis of sarcomatoid mesothelioma had most likely been much abused in the past, and that it should now be regarded as a diagnosis of exclusion.
  • No truly specific stain existed for mesothelioma. Panels were used instead: the most frequently used positive markers were CK5/6, calretinin and WT1, and the most frequently used negative markers were carcinoembryonic antigen, MOC31 and thyroid transcription factor-1.
  • Immunohistochemistry was described as of limited value for separating benign from reactive, and reactive from malignant, mesothelial cells.
  • Electron microscopy was described as still regarded as the gold standard for diagnosing well-differentiated epithelioid malignant mesothelioma.
  • The authors stated that the role of SV40 in causing malignant mesothelioma is still debatable, noting no epidemiologic support for a causative role.
• The authors' conclusion: The authors concluded that molecular research had so far played a very limited role in diagnosis, that further studies were needed to validate existing data, and that diagnosis still depended on a multidisciplinary approach.

Topics

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

Medical terms in this study, explained in our Lexicon: Mesothelioma, Pleura, Neoplasm, Asbestos Exposure, Well-Differentiated.

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