Background: Immunohistochemical reactivity to carcinoembryonic antigen (CEA) is often used to exclude the diagnosis of malignant mesothelioma.
Methods: In a study comprising 61 malignant mesotheliomas and 20 adenocarcinomas, the reactivity against one polyclonal and five different monoclonal anti-CEA antibodies was tested.
Results: Thirteen of the mesotheliomas showed distinct reactivity to the polyclonal antiserum, even after absorption with spleen powder. Of the monoclonal preparations, those staining granulocytes and macrophages also showed varying reactivity to some of these 13 mesotheliomas. Only one monoclonal antibody showed no such reactivity and labeled no mesothelioma case, while its capacity to stain adenocarcinomas remained.
Conclusions: Mesotheliomas may contain substances that share epitopes with the CEA molecule. Only one of the tested monoclonal antibodies seemed sufficiently specific to be used diagnostically as a single immunohistochemical parameter to exclude malignant mesothelioma.