Immunocytochemical panel for the identification of malignant cells in serous effusions

Our plain-English summary of Immunocytochemical panel for the identification of malignant cells in serous effusions, by K.V. Nance, J.F. Silverman (American Journal of Clinical Pathology, 1991).

The study

• Authors: K.V. Nance, J.F. Silverman
• Journal: American Journal of Clinical Pathology
• Published: 1991;95(6):867-74
• Cited by: 60 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The cytologic diagnosis of malignancy in serous effusions can be challenging. An immunocytochemical (ICC) panel using commercially available antibodies (to carcinoembryonic antigen [CEA], epithelial membrane antigen [EMA], B72.3, Leu-M1, cytokeratin [CK], leukocyte common antigen [LCA], S-100 protein, and vimentin) was applied to cell blocks fixed in methyl Carnoy's solution that were from 55 consecutive pleural, peritoneal, and pericardial fluid specimens. The results were correlated with data from clinical records and routine cytologic studies. Final cytologic diagnoses included 26 of adenocarcinoma and 1 of mesothelioma. The remaining 28 cases were considered to be benign (reactive) proliferations. EMA, CEA, B72.3, and Leu-M1 were present in 96%, 77%, 58%, and 42% of adenocarcinomas, respectively. These determinants were absent in the mesothelioma and the reactive effusions, although anti-CEA yielded strong background staining of inflammatory cells. The CK markers identified malignant cells in 93% of cases, but consistently stained mesothelial cells as well. Antivimentin strongly labeled mesothelial cells in all cases, with weak to absent staining of malignant cells. In 3 of 26 carcinoma cases (12%), the ICC panel identified malignant cells that were not recognized initially on routine cytologic examination. In 1 of 26 cases (4%), the panel was falsely negative. Use of this approach can improve the diagnostic accuracy of cytologic examination of serous fluids. The ICC panel is especially helpful when atypical mesothelial proliferation is present, or in cases that are clinically suspect for malignancy, but cytologically negative because there are only a few malignant cells, or those that are cytologically bland.

In plain English

This laboratory study tested whether antibody stains could help pathologists find cancer cells in fluid from around the lungs, abdomen or heart. The authors applied nine antibody stains to 55 consecutive fluid samples. Final diagnoses were 26 adenocarcinomas, 1 mesothelioma and 28 benign reactive conditions. EMA, CEA, B72.3 and Leu-M1 stained cancer cells in 96%, 77%, 58% and 42% of the adenocarcinomas. None of these four stained the mesothelioma, and none flagged cancer in the benign samples, although the CEA stain caused strong background staining of inflammatory cells and some lining (mesothelial) cells. The keratin stains marked cancer cells in 93% of cases, including the mesothelioma, but also stained benign mesothelial cells in every case. The mesothelioma stained strongly for vimentin. The panel found cancer cells missed on routine examination in 3 of 26 carcinoma cases, and it was falsely negative in 1 of 26. The authors concluded the panel can help improve accuracy, but that malignancy should never be diagnosed from one positive marker alone. The study included only one mesothelioma, and the article does not discuss asbestos.

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: Diagnostic laboratory study evaluating an immunocytochemical (antibody staining) panel on fluid cell blocks, with results compared against routine cytology, clinical records and surgical pathology
• Who was studied: 55 consecutive pleural, peritoneal and pericardial fluid specimens. Final diagnoses were 26 adenocarcinomas, 1 mesothelioma (primary site listed as pleura) and 28 benign reactive effusions. Patient numbers, location and dates of collection are not stated.
• Exposure: No asbestos or other environmental or occupational exposure was studied. The study tested antibody stains (to EMA, CEA, B72.3, Leu-M1, high and low molecular weight cytokeratins, vimentin, S-100 protein and LCA) on fluid samples.
• Main results:
  • In the 26 adenocarcinomas, EMA, CEA, B72.3 and Leu-M1 stained the malignant cells in 96%, 77%, 58% and 42% of cases respectively
  • EMA, CEA, B72.3 and Leu-M1 did not stain the single mesothelioma or the reactive (benign) effusions. Polyclonal anti-CEA did, however, produce strong background staining of inflammatory cells.
  • In the Discussion, the authors noted that the CEA background staining involved inflammatory cells and some mesothelial cells in a number of cases
  • Keratin antibodies marked malignant cells in 93% of cases, including the mesothelioma, but also stained benign mesothelial cells in 100% of cases
  • The single mesothelioma stained strongly for vimentin. Vimentin also marked malignant cells to variable degrees in 42% of the carcinomas.
  • In 3 of 26 carcinoma cases (12%), the panel identified malignant cells not recognized initially on routine cytology
  • In 1 of 26 cases (4%), the panel was falsely negative. There were no false positives among the benign cytologic diagnoses.
  • S-100 protein and LCA were not diagnostically useful as part of the routine panel
• The authors' conclusion: The authors concluded that an immunocytochemical panel can help improve the accuracy of cytologic examination of serous fluids. They also stated that a diagnosis of malignancy should never rest on one positive marker alone, but must be correlated with cytologic atypia and clinical data.
• Limitations the authors state:
  • Only one mesothelioma was included. It was EMA negative, but the authors noted they had seen weak EMA labeling in other mesotheliomas.
  • The polyclonal anti-CEA antibody used gave nonspecific background staining of inflammatory cells and some mesothelial cells
  • The authors called their suggestion that staining patterns may indicate a tumor's origin speculation that is difficult to confirm statistically

Topics

Medical terms in this study, explained in our Lexicon: Carcinoembryonic Antigen (CEA), Epithelial Membrane Antigen (EMA), B72.3 (TAG-72), S-100, Cell Block, Pericardial, Adenocarcinoma, Mesothelioma.

Related studies

• The utility of ancillary techniques in effusion cytology — K.V. Nance, J.F. Silverman (1992)
• Root cause analysis of indeterminate diagnoses in serous fluids cytopathology — H.N. Gokozan, A. Harbhajanka, et al. (2021)
• Quality control of immunocytochemical staining of effusions using a standardized method of cell processing — V. Kuenen-Boumeester, P. van Loenen, et al. (1996)
• Morphologic and immunocytochemical performances of effusion cell blocks prepared using 3 different methods — X. Jing, Q.K. Li, et al. (2013)
• Immunocytochemical staining of serous effusions with the monoclonal antibody Ber-EP4 — M. De Angelis, I.D. Buley, et al. (1992)
• A panel of markers for identification of malignant and non-malignant cells in culture from effusions — F.P. Carneiro, M.I. Muniz-Junqueira, et al. (2017)

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