PE
Excitation: 565nm, Emission: 578nm
Cell adhesion receptors (CAMs) are actively involved in regulating various cell processes, including growth, differentiation, and cell death. Therefore, CAMs represent a large group of morphoregulating molecules, mediating cross-talk between cells and of cells with their environment. From this perspective, CAMs do contribute to cells and tissue organization, and in diseased tissue, to the disease development and biological characteristics. Therefore, observed changes in expression patterns of adhesion molecules may contribute to establish a diagnosis. A distinct shift in expression patterns in neoplastic epithelium has been described, for example for cadherins, integrins, and CD44. A relatively novel cell CAM, Ep-CAM, was first reported to be a pan-carcinoma antigen, although it is rather a marker of epithelial lineage. Several antibodies directed to Ep-CAM have been generated, and many epithelial tissues and their neoplastic appendages have been studied. This article outlines the results of these studies. Based on the results of these studies, we conclude that Ep-CAM immunohistochemistry can be a useful tool in the diagnosis of disturbed epithelial tissues.
Epithelial glycoprotein EGP-2 and carcinoembryonic antigen (CEA) are transmembrane glycoproteins and cell surface markers. Eighty-four colorectal tumors including 23 adenomas (2 mild, 13 moderate, and 8 severe atypia) and 61 adenocarcinomas (33 well- and 28 moderately differentiated) as well as adjacent normal colonic mucosa (51 cases) were studied for the immunolocalization of EGP-2 as detected by the monoclonal antibody VU-1D9, and compared with CEA expression. In the normal colonic mucosa, basolateral VU-1D9 expression in the surface epithelial cells was constantly seen in all 51 cases, while weak apical CEA staining in the surface epithelium was seen in 25% (13/51) of the cases. In 91% (21/23) of the adenomas, regardless of the grade of atypia, VU-1D9 labeled the basolateral membrane of a few surface lining cells leaving atypically proliferating glands negative, while CEA expressed strong apical staining in the surface epithelial cells as well as atypically proliferating glands. The well-differentiated adenocarcinomas showed homogeneous basolateral staining for VU-1D9 and strong apical staining for CEA; the moderately differentiated adenocarcinomas showed membranous as well as cytoplasmic VU-1D9 staining and luminal as well as cytoplasmic CEA staining. The VU-1D9 and CEA localizations and the stage of expression in relation to tumor progression were completely different. Strong CEA expression was seen in the adenomatous stage, while the homogeneous VU-1D9 expression required tumor progression to the carcinomatous stage. VU-1D9 especially when applied in combination with CEA, will be a useful marker for colorectal lesions, and its reactivity patterns in carcinoma can predict the prognosis.