Immunohistochemistry in the Distinction Between Malignant Mesothelioma and Pulmonary Adenocarcinoma: a Critical Evaluation of New Antibodies

J Clin Pathol 2002 Sep;55(9):662-8 (ISSN: 0021-9746) Abutaily AS; Addis BJ; Roche WR
Respiratory Cell and Molecular Biology, University of Southampton, University of Southampton, Southampton General Hospital, UK. AIM:

The value of immunohistochemical staining in differentiating between malignant mesothelioma and pulmonary adenocarcinoma was re-examined using newly available commercial antibodies, with the aim of increasing the sensitivity and specificity of diagnosis, and simplifying the antibody panel required.

METHODS: Forty one malignant mesotheliomas and 35 lung adenocarcinomas were studied. Commercial antibodies to calretinin, E-cadherin, N-cadherin, surfactant apoprotein A (SP-A), thyroid transcription factor 1 (TTF-1), thrombomodulin, and cytokeratin 5/6 were applied using the streptavidin-biotin-peroxidase complex procedure on formalin fixed, paraffin wax embedded tissue.

RESULTS: E-cadherin was expressed in all adenocarcinomas and in 22% of the mesotheliomas. TTF-1 expression was detected in 69% of the adenocarcinomas and none of the mesotheliomas. Positive staining with polyclonal anticalretinin was detected in 80% of the mesotheliomas and 6% of the adenocarcinomas. N-cadherin was expressed in 78% of mesotheliomas and 26% of adenocarcinomas. Thrombomodulin was expressed in 6% of the adenocarcinomas and in 53% of the mesotheliomas. Cytokeratin 5/6 expression was detected in 6% of the adenocarcinomas and 63% of the mesotheliomas. The results were compared with the standard laboratory panel for mesothelioma diagnosis: anticarcinoembryonic antigen (anti-CEA), LeuM1, BerEP4, and HBME-1.

CONCLUSION: Of the antibodies used in this study, E-cadherin was 100% sensitive for pulmonary adenocarcinoma and TTF-1 was 100% specific for pulmonary adenocarcinoma. The application of these two antibodies alone was adequate for the diagnosis of 69% of adenocarcinomas and 78% of mesotheliomas. Where TTF-1 is negative and E-cadherin is positive, a secondary panel of antibodies, including BerEP4 and LeuM1 (CD15) and antibodies directed against CEA, calretinin, cytokeratin 5/6, thrombomodulin, and N-cadherin, is required for differentiation between malignant mesothelioma and pulmonary adenocarcinoma.

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CAS Registry / EC Numbers

Adenocarcinoma [diagnosis] Lung Neoplasms [diagnosis] Mesothelioma [diagnosis] Tumor Markers, Biological [metabolism]
Adenocarcinoma [metabolism] Antibodies, Monoclonal [immunology] Cadherins [metabolism] Diagnosis, Differential Immunoenzyme Techniques Lung Neoplasms [metabolism] Mesothelioma [metabolism] Neoplasm Proteins [metabolism] Nuclear Proteins [metabolism] Sensitivity and Specificity Transcription Factors [metabolism]
0 (Antibodies, Monoclonal) 0 (Cadherins) 0 (Neoplasm Proteins) 0 (Nuclear Proteins) 0 (Transcription Factors) 0 (Tumor Markers, Biological) 0 (thyroid nuclear factor 1)

*** POSTED OCTOBER 14, 2002 ***