Identification of basement membrane components and intermediate filaments in calcifying epithelial odontogenic tumors

An immunohistochemical technique was used on paraffin-embedded tissues of four cases of calcifying epithelial odontogenic tumors (CEOT). These studies were performed to gain an additional understanding of the nature of amyloid-like deposits in these tumors. For these studies antibodies to Type IV collagen, laminin, and the five classes of intermediate filament proteins were employed. In all of the tumors examined basement membrane components and intermediate filament proteins (cytokeratin) were demonstrated both in the epithelial tumor islands and within the extracellular amyloid-like deposits. Antibodies to vimentin intermediate filaments were localized only in the stromal fibroblasts. Limited proteolysis or the use of a chaotropic agent was required to express the antigenic determinants present. These studies substantiate the presence of basement membrane components in the amyloid-like deposits of CEOT. In addition, these extracellular deposits are shown to be heterogenous in composition by the immunohistochemical demonstration of cytokeratin intermediate filament proteins.