The diagnostic implications of variable cytokeratin expression in mesotheliomas

Our plain-English summary of The diagnostic implications of variable cytokeratin expression in mesotheliomas, by F.G. Mayall, H. Goddard, A.R. Gibbs (The Journal of Pathology, 1993).

The study

• Authors: F.G. Mayall, H. Goddard, A.R. Gibbs
• Journal: The Journal of Pathology
• Published: 1993;170(2):165-8
• Cited by: 12 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Immunostaining for cytokeratin has a well-established diagnostic application in distinguishing sarcomatous mesotheliomas from sarcomas based on the premise that cytokeratin expression is common in mesotheliomas but very rare in sarcomas. However, the frequency of cytokeratin detection is highly dependent on the choice of antibody. The aim of this study was to examine the distribution of simple cytokeratins and stratified cytokeratins in 45 mesotheliomas of various types and to assess the diagnostic utility of a simple cytokeratin antibody, a stratified cytokeratin antibody, and a broad spectrum cytokeratin antibody with the aim of establishing the superiority of one for routine diagnostic use. Particular attention was paid to the potential utility of these antibodies in biopsy specimens. The broad spectrum cytokeratin antibody performed better than both the simple cytokeratin antibody (paired t-test: P < 0.01) and the stratified cytokeratin antibody (P < 0.01) as a diagnostic marker of mesothelioma and should be used in preference to the other two antibodies, particularly when considering small biopsy specimens.

In plain English

This laboratory pathology study, from Llandough Hospital, Penarth, and the University of Wales College of Medicine, did not study asbestos exposure. It compared three antibody stains for cytokeratin (a protein found in mesothelioma cells) in tissue blocks from 45 mesotheliomas: 13 epithelial, 13 sarcomatous and 19 biphasic. The stains were a simple cytokeratin antibody, a stratified cytokeratin antibody, and a broad spectrum cytokeratin antibody. Each slide was scored by how many of 20 microscope fields stained positive. Each field was about the size of a small biopsy, so the authors treated it as a 'mock biopsy'. In this mock biopsy scoring, the broad spectrum antibody was significantly more sensitive than the other two (paired t-test, P less than 0.01 for each comparison). In no tumour did it do worse than either of the others. The stratified antibody did worst in sarcomatous mesotheliomas. The authors concluded that the broad spectrum antibody should be preferred, particularly for small biopsy specimens. They noted that formalin fixation of the tissue made the results harder to interpret, and that cytokeratin staining alone does not diagnose 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 comparing three cytokeratin antibodies on archived mesothelioma tissue
• Who was studied: Tissue from 45 mesotheliomas (13 epithelial, 13 sarcomatous, 19 biphasic), from post-mortem and surgical material, Llandough Hospital, Penarth, U.K.; collection dates not given
• Exposure: Not an asbestos exposure study. Exposures compared were three monoclonal antibodies: simple cytokeratin (SCK), stratified cytokeratin (StCK) and broad spectrum cytokeratin (BCK)
• Main results:
  • In mock biopsy scoring of all mesotheliomas, the broad spectrum antibody was significantly more sensitive than the simple antibody (paired t-test P less than 0.01) and the stratified antibody (P less than 0.01)
  • In no individual tumour did the broad spectrum antibody perform worse than either of the other two
  • The stratified antibody favoured the epithelial part of the tumours and performed worst in sarcomatous mesotheliomas. In the table, sarcomatous cases (13) were positive in 61% of sections and 60% of mock biopsies for the broad spectrum antibody, 46% and 18% for the stratified antibody, and 46% and 42% for the simple antibody (column order as printed in the table headings)
  • Across all 45 cases, positivity was 86% of sections and 86% of mock biopsies for the broad spectrum antibody, 82% and 71% for the stratified antibody, and 80% and 69% for the simple antibody (column order as printed in the table headings)
• The authors' conclusion: The authors concluded that how useful cytokeratin staining is as a marker of mesothelioma depends heavily on the antibody used, especially in small biopsies, and that the broad spectrum antibody performed best in all three types of mesothelioma
• Limitations the authors state:
  • Formalin fixation reduces cytokeratin antigenicity, creating uncertainty about what is fixation artefact
  • Cytokeratin positivity in pleural lesions is not by itself diagnostic of mesothelioma

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, Sarcoma, Biopsy.

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