The calcium binding protein calretinin is a selective marker for malignant pleural mesotheliomas of the epithelial type

Our plain-English summary of The calcium binding protein calretinin is a selective marker for malignant pleural mesotheliomas of the epithelial type, by V. Gotzos, P. Vogt, M.R. Celio (Pathology, Research and Practice, 1996).

The study

• Authors: V. Gotzos, P. Vogt, M.R. Celio
• Journal: Pathology, Research and Practice
• Published: 1996;192(2):137-47
• Cited by: 106 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

In a series of 23 cases of mesothelioma of either the epithelial, sarcomatoid or the mixed type, the expression of three calcium-binding proteins (calretinin, parvalbumin and calbindin-D28k) was studied using immunohistochemical techniques on paraffin sections. The results show that calretinin is expressed in mesotheliomas of the epithelial type (papillary, adenomatous or solid) and by the epithelial component of the mixed tumours. The immunohistochemical reaction is specific and reproducible. The tissues of the pulmonary parenchyma and of the pleura are negative for calretinin except for the rare fibroblasts and some skeletal muscle fibres situated in the interstices of, or near the epithelial tumour mass. The sarcomatoid mesotheliomas and the sarcomatoid component of the mixed tumours do not express calretinin. Parvalbumin and calbindin-D28k are expressed neither in mesotheliomas nor in normal lung tissue. Primary adenocarcinomas of the lung are negative for all three calcium binding proteins cited. Thus, calretinin seems to represent a selective marker for mesotheliomas of the epithelial type and allows their differentiation from metastases of lung adenocarcinomas.

In plain English

This laboratory study used immunohistochemical staining on paraffin-embedded tissue to look for three calcium-binding proteins (calretinin, parvalbumin and calbindin-D28k). It examined 23 malignant pleural mesotheliomas and 4 primary lung adenocarcinomas from a Zürich, Switzerland, pneumoconiosis research collection. The mesotheliomas were 7 epithelial type, 1 sarcomatoid and 15 mixed (biphasic), mostly taken at autopsy. Parvalbumin and calbindin-D28k were not found in any mesothelioma or in normal tissue. Calretinin was found in all epithelial-type mesotheliomas and in the epithelial part of all mixed tumours, in 70% to 90% of non-dividing tumour cells. The sarcomatoid tumour and the sarcomatoid parts of mixed tumours were negative. The lung adenocarcinomas were negative apart from very rare weakly stained cells, and 8 more lung carcinomas, reported in an addendum, were also negative. Flattened normal mesothelial cells were negative, while cuboidal (transformed) mesothelial cells stained strongly. The authors concluded that calretinin may be a selective positive marker for epithelial-type mesothelioma. They noted that it does not mark mesothelial cells exclusively and that further research is needed.

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 tumour tissue (paraffin sections)
• Who was studied: 23 cases of human malignant pleural mesothelioma (7 epithelial type, 1 sarcomatoid, 15 mixed biphasic type) and 4 primary lung adenocarcinomas from the collection of the Zürich "Pneumoconiosis research group", Switzerland. Specimens were taken most often at autopsy. Table 1 lists 22 of the mesothelioma cases as male and 1 as female.
• Exposure: The study did not analyse asbestos exposure. The exposure examined was staining with antibodies against calretinin, parvalbumin and calbindin-D28k. Ferruginous body counts per gram of fresh tissue were listed for the mesothelioma cases in Table 1, but they were not compared with the staining results.
• Main results:
  • Parvalbumin and calbindin-D28k staining was negative in all three types of mesothelioma and in normal tissue.
  • Epithelial-type mesotheliomas and the epithelial component of mixed mesotheliomas stained for calretinin. The authors report finding calretinin in all epithelial-type cases and in the epithelial component of all mixed cases.
  • In these tumours, calretinin staining was in the cytoplasm of 70% to 90% of non-dividing (interphase) cells. Between 10% and 30% of these cells stayed negative, and all dividing (mitotic) cells were positive.
  • Calretinin was not expressed in the sarcomatoid-type mesothelioma or in the sarcomatoid component of mixed tumours.
  • The 4 primary lung adenocarcinomas were negative for calretinin, except for very rare weakly immunoreactive vacuolized cells.
  • In an addendum, 8 additional lung carcinomas tested with calretinin antibodies were all negative.
  • Flattened (normal) pleural mesothelial cells were negative for calretinin, while cuboidal (transformed) mesothelial cells were strongly positive.
  • Surrounding lung tissue and blood vessels were negative for calretinin. Certain fibroblastic cells among the tumour and a limited number of skeletal muscle fibres near epithelial-type tumour were positive.
• The authors' conclusion: The authors concluded that calretinin is expressed specifically and reproducibly in epithelial-type mesothelioma and in the epithelial component of mixed tumours, but not in sarcomatoid tumour or lung adenocarcinoma. They concluded that it may therefore be a selective positive marker that could help tell epithelial-type mesothelioma apart from metastases of lung adenocarcinoma.
• Limitations the authors state:
  • The authors state that the calretinin antibody does not mark mesothelial cells exclusively. They report in unpublished work that it reacts with tumour cells from 5% to 10% of human colonic adenocarcinomas, and they state that further research is needed before an antibody is useful for distinguishing carcinomas that have spread to the lung or pleura.
  • The authors note that calretinin staining also occurs in morphologically transformed (reactive) mesothelial cells and could reflect a nonspecific reaction rather than cancer.

Topics

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

Medical terms in this study, explained in our Lexicon: Calretinin, Pleural Mesothelioma, Mesothelioma, Sarcomatoid, Parenchyma, Pleura, Fibroblast, Adenocarcinoma.

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