Calretinin. A selective marker of normal and neoplastic mesothelial cells in serous effusions

Our plain-English summary of Calretinin. A selective marker of normal and neoplastic mesothelial cells in serous effusions, by M.C. Barberis, M. Faleri, S. Veronese, et al (Acta Cytologica, 1997).

The study

• Authors: M.C. Barberis, M. Faleri, S. Veronese, C. Casadio, G. Viale
• Journal: Acta Cytologica
• Published: 1997;41(6):1757-61
• Cited by: 77 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objective: To document that a polyclonal antiserum to calretinin, a 29-kd calcium-binding protein, consistently decorates normal and tumor mesothelial cells in cytologic preparations.

Study Design: Thirty-three archival cytologic specimens from eight patients with histologically confirmed malignant mesothelioma and 13 from patients with metastatic serous effusions were destained and then immunostained with anticalretinin antiserum. For investigation of cell suspensions, four pleural fluids were incubated with anticalretinin antiserum. After cytocentrifugation the specimens were stained in accordance with the alkaline phosphatase anti-alkaline phosphatase (APAAP) method. For electron microscopic examination the cell suspensions were then incubated with gold-labeled antirabbit antibody.

Results: The diagnostic sensitivity of this new immunocytochemical approach reached 100% for the eight malignant mesotheliomas investigated. Only 3 of the 13 adenocarcinomas metastatic to the serous membranes included in this study were weakly reactive, accounting for 81% specificity. Binding of anticalretinin antiserum to living mesothelial cells was consistently documented in all four cases investigated.

Conclusion: Calretinin is a very useful marker for positive identification of normal and tumor mesothelial cells in serous effusions.

In plain English

This laboratory study from Milan, Italy, tested whether a stain for calretinin, a calcium-binding protein, identifies mesothelial cells in pleural or peritoneal fluids (serous effusions). The authors destained and immunostained 33 archived fluid specimens collected from 1993 to 1996. Twenty came from eight patients with malignant mesothelioma. Thirteen were effusions from adenocarcinomas that had spread from the lung, stomach, ovary, breast or endometrium. All 20 mesothelioma preparations stained for calretinin, strongly and diffusely in more than 75% of tumor cells. In 10 of the 13 metastatic cases the tumor cells did not stain, although the accompanying normal or activated mesothelial cells did. In three cases (two breast, one stomach), 10 to 50% of tumor cells stained faintly. The authors reported this as 81% specificity. In fresh fluid from four patients, the antiserum bound to living mesothelial cells in all four, while tumor and inflammatory cells were negative. The authors concluded that calretinin is a very useful marker for identifying normal and tumor mesothelial cells in effusions. They suggested combining it with adenocarcinoma markers because some metastatic effusions also stain weakly.

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: archived cytology slides were destained and immunostained for calretinin, plus a small prospective experiment on fresh cell suspensions
• Who was studied: 33 cytologic specimens of pleural or peritoneal fluid collected 1993 to 1996 at Ospedale Niguarda Ca' Granda, Milan. Of these, 20 specimens came from eight patients with malignant mesothelioma (confirmed by histology in 4 of 8 and by ultrastructural examination in 8 of 8). The other 13 were metastatic pleural (7) or peritoneal (6) effusions from adenocarcinomas of the lung (4), stomach (2), ovary (4), breast (2) and endometrium (1). Separately, fresh pleural fluids from four patients were studied: two with metapneumonic pleurisy and two with metastatic adenocarcinoma of the breast and the ovary.
• Exposure: The article does not report asbestos or any other exposure. What was studied was immunostaining with a polyclonal anticalretinin antiserum.
• Main results:
  • All 20 cytologic preparations from the malignant mesotheliomas stained for calretinin, strongly and diffusely in more than 75% of tumor cells.
  • In 10 of 13 metastatic serous effusions, the tumor cells showed no calretinin staining, while the accompanying normal or activated mesothelial cells were strongly labeled.
  • In 3 of the 13 metastatic cases (two infiltrating ductal carcinoma of the breast, one adenocarcinoma of the stomach), 10 to 50% of tumor cells showed faint staining.
  • The authors reported 81% specificity for the metastatic adenocarcinomas and 100% sensitivity for the eight malignant mesotheliomas.
  • Fisher's exact test showed a significant correlation between calretinin staining and mesothelioma effusions (two-tailed P value .0010).
  • In fresh fluid from all four patients tested, the antiserum bound to living mesothelial cells; tumor and inflammatory cells were negative.
• The authors' conclusion: The authors concluded that calretinin is a very useful marker for positively identifying normal and tumor mesothelial cells in serous effusions.
• Limitations the authors state:
  • The authors noted that metastatic effusions may also show weak calretinin staining in a small percentage of cases. They suggested using calretinin together with markers for adenocarcinoma cells.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma, Pleural plaques and thickening.

Medical terms in this study, explained in our Lexicon: Calretinin, Mesothelial Cells, Malignant Mesothelioma, Adenocarcinoma.

Related studies

• Comparison of antibodies to HBME-1 and calretinin for the detection of mesothelial cells in effusion cytology — P.A. Fetsch, A. Simsir, et al. (2001)
• MMP-7 is a highly specific negative marker for benign and malignant mesothelial cells in serous effusions — B. Davidson, H.T. Stavnes, et al. (2016)
• The value of anti-calretinin antibody in the differential diagnosis of normal and reactive mesothelia versus metastatic tumors in effusion cytology — H. Nagel, B. Hemmerlein, et al. (1998)
• The calcium binding protein calretinin is a selective marker for malignant pleural mesotheliomas of the epithelial type — V. Gotzos, P. Vogt, et al. (1996)
• Cytological differential diagnosis among adenocarcinoma, epithelial mesothelioma, and reactive mesothelial cells in serous effusions by immunocytochemistry — X.Y. Su, G.D. Li, et al. (2011)
• Ber-EP4 for differentiating adenocarcinoma from reactive and neoplastic mesothelial cells in serous effusions. Comparison with carcinoembryonic antigen, B72.3 and Leu-M1 — M.E. Bailey, R.W. Brown, et al. (1996)

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