E-cadherin, E-selectin and vascular cell adhesion molecule: immunohistochemical markers for differentiation between mesothelioma and metastatic pulmonary adenocarcinoma?

Pleural mesotheliomas, especially pure epithelioid mesotheliomas, may histologically be easily confused with peripheral pulmonary adenocarcinomas or pleural carcinosis. As there is no specific antibody for mesotheliomas, today a panel of immunohistochemical markers is used for the differential diagnosis of these two tumour entities. In search of further significant antibodies for application onto formalin-fixed, paraffin-embedded tissue, we immunohistochemically investigated the expression pattern of three adhesion molecules: vascular cell adhesion molecule (VCAM), E-selectin and E-cadherin. A comparatively large number of 44 mesotheliomas (15 epithelioid, 15 biphasic, 14 sarcomatoid) and 18 peripheral pulmonary adenocarcinomas were analysed. While for these two tumour entities there were no significant differences of the staining patterns for VCAM and E-selectin, there were significant differences in the expression of E-cadherin: while nearly all adenocarcinomas stained positively, there was almost no staining reaction of the mesotheliomas. Therefore, E-cadherin -- in contrast to E-selectin and VCAM -- appears to be a further relevant immunohistochemical marker for the distinction between adenocarcinomas and mesotheliomas.