Immunohistochemical detection of amelogenin and cytokeratin 19 in epithelial odontogenic tumors

OBJECTIVE: Epithelial odontogenic tumors exhibit considerable histological variation and are classified into several benign and malignant entities. Ex pression of amelogenin and cytokeratin 19 (CK19), that are potentially usef ul polypeptides for identification of odontogenic epithelial components, wa s evaluated in various types of epithelial odontogenic tumors. MATERIALS AND METHODS: Specimens of 33 ameloblastomas, three calcifying epi thelial odontogenic tumors (CEOTs), two clear cell odontogenic tumors (CCOT s) and five malignant ameloblastomas were examined by immunohistochemistry using anti-amelogenin and anti-CK19 antibodies. RESULTS: Immunohistochemical reactivity for amelogenin was detected in many peripheral columnar or cuboidal cells and some central polyhedral cells in ameloblastomas, and histological variants showed various degrees of amelog enin expression. Expression of CK19 was diffusely present in neoplastic cel ls in ameloblastomas, and decreased expression was found in keratinizing ce lls of acanthomatous variants and some neoplastic cells of desmoplastic var iants. In CEOTs, immunohistochemical reactivity for amelogenin was detected in neoplastic cells and intercellular amyloid-like materials. whereas CK19 was expressed in neoplastic cells. CCOTs showed positive reactivity for am elogenin and CK19 in neoplastic cells. Malignant ameloblastomas exhibited v arious degrees of amelogenin expression with constant CK19 expression in ne oplastic cells. CONCLUSION: Diverse types of epithelial odontogenic tumors express amelogen in and CK19, suggesting that these tumors have ameloblastic differentiation or odontogenic epithelial properties.