Malignant Pleural Mesothelioma-Does Ki67 Make the Grade?

Our plain-English summary of Malignant Pleural Mesothelioma-Does Ki67 Make the Grade?, by O.W.J. Prall (JTO Clinical and Research Reports, 2021).

The study

• Author: O.W.J. Prall
• Journal: JTO Clinical and Research Reports
• Published: 2021;2(5):100170
• Type of article: Editorial
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

In plain English

This is an editorial, not an original study. The author, a pathologist at the Peter MacCallum Cancer Centre in Melbourne, Australia, commented on a study by Belderbos and colleagues in the same journal issue. That study examined tissue features of malignant pleural mesothelioma that might predict recurrence. According to the editorial, Belderbos and colleagues concluded that Ki67, a marker of actively dividing tumor cells, was the strongest prognostic factor for overall and progression-free survival. The author described that study as small and retrospective, with 27 patients who were all treated with extended pleurectomy/decortication, which raised the possibility of selection bias. The author said its findings agreed with earlier studies. The author then discussed whether Ki67 should be used to grade mesothelioma. The editorial compared Ki67 with counting dividing cells (mitotic figures) and noted practical problems: there is no agreed counting method, the right cutoff is uncertain (other studies proposed 10%, 15%, 20% and 30%), and small biopsies are hard to assess. The author concluded that only large, well-designed prospective studies in different populations could define how to grade the disease. The editorial 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: Editorial commenting on another study (Belderbos et al.) and on earlier research; no original data
• Who was studied: No population of its own. The editorial discusses the Belderbos et al. study of 27 patients with malignant pleural mesothelioma treated with extended pleurectomy/decortication.
• Main results:
  • The editorial reports that Belderbos et al. (not this article) concluded that Ki67 was the strongest prognostic factor for overall survival and progression-free survival.
  • The author said the Belderbos findings agreed with several earlier studies that also found Ki67 had prognostic significance in malignant pleural mesothelioma.
  • The author noted that other studies proposed different Ki67 cutoffs: 15% and 20%. A multi-institutional study of 940 patients found a 30% cutoff prognostic.
  • The author pointed to breast cancer as an example. There, Ki67 has prognostic significance but is not officially recommended, because there is no consensus on scoring method or cutoffs.
  • The author suggested that specifying a minimum number of tumor cells to count would be more appropriate than the 2 mm2 area that Belderbos et al. used.
  • The author said the apparent lack of variation in Ki67 labeling within tumors, reported by Belderbos et al., would need confirmation in a larger series.
• The authors' conclusion: The author concluded that only large, well-designed prospective studies in different populations will be able to define how to grade malignant pleural mesothelioma and what contribution Ki67 will make.
• Limitations the authors state:
  • The author noted that the Belderbos et al. study being discussed was small and retrospective, and that all its patients received the same unusual surgery, raising the possibility of selection bias.

Topics

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma.

Related studies

• Does Chromothripsis Make Mesothelioma an Immunogenic Cancer? — M. Carbone, H. Yang, et al. (2019)
• Grade 4 asbestosis does not extend directly from the respiratory bronchiole to the peripheral lung — Y. Kawabata, T. Kasai, et al. (2018)
• Cigarette smoke makes airway and early parenchymal asbestos-induced lung disease worse in the guinea pig — V. Tron, J.L. Wright, et al. (1987)
• 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)
• The Correlation of Serum Mesothelin Level With Pleural Thickness in Malignant Pleural Mesothelioma Makes it a Valuable Tool for Monitoring Tumor Progression — V. Fontana, A. Vigani, et al. (2019)
• Pathogenesis of Fibrosis Produced by Asbestos and Man-Made Mineral Fibers: What Makes a Fiber Fibrogenic? — A. Churg, J. Wright, et al. (2000)

Browse more research in JTO Clinical and Research Reports, or return to medical research.