CARCINOEMBRYONIC ANTIGEN-LIKE REACTIVITY IN MALIGNANT MESOTHELIOMA - A COMPARISON BETWEEN DIFFERENT COMMERCIALLY AVAILABLE ANTIBODIES

Background. Immunohistochemical reactivity to carcinoembryonic antigen (CEA) is often used to exclude the diagnosis of malignant mesotheliom a. Methods. In a study comprising 61 malignant mesotheliomas and 20 ad enocarcinomas, the reactivity against one polyclonal and five differen t 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 preparatio ns, those staining granulocytes and macrophages also showed varying re activity to some of these 13 mesotheliomas. Only one monoclonal antibo dy showed no such reactivity and labeled no mesothelioma case, while i ts capacity to stain adenocarcinomas remained. Conclusions. Mesothelio mas may contain substances that share epitopes with the CEA molecule. Only one of the tested monoclonal antibodies seemed sufficiently speci fic to be used diagnostically as a single immunohistochemical paramete r to exclude malignant mesothelioma.