The usual immunohistochemical positivity of pleural mesotheliomas for cytokeratin (CK 5/6), calretinin, and HBME-1 with negative staining for carcinoembryonic antigen (CEA), B72.3, and Leu-M1, holds true for the pericardial variety. This evidence concerns the gene CEACAM5 and pleural mesothelioma.