Co-expression of hepatocyte growth factor and c-met in epithelial odontogenic tumors

Hepatocyte growth factor (HGF) and its receptor, c-met, have been shown to regulate cell proliferation, motility and morphology in a variety of cell types. A significant role of the HGF/c-met pathway has been demonstrated in various tumors, however, little is known about the role of HGF/c-met pathway in odontogenic tumors. The aim of this study was to characterize the expression of HGF and c-met in 30 ameloblastomas, 7 unicystic ameloblastomas (luminal type), 10 calcifying cystic odontogenic tumors, 10 adenomatoid odontogenic tumors (AOTs), 30 keratocytic odontogenic tumors (KCOTs) and 6 ameloblastic carcinomas using an immunohistochemical method. HGF and c-met were generally immunolocalized in the cytoplasm of all epithelial tumor cells, except for keratinizing cells in acanthomatous ameloblastoma, in all the examined odontogenic tumors. These results, together with the expression of these two proteins in the epithelium of tooth germs, suggest that the HGF/c-met pathway is involved in the differentiation of odontogenic tumors. This pathway may also promote tumor proliferation in odontogenic tumors due to its potent mitogenic effect. The consistent and strong immunolocalization of HGF and c-met in squamous cells present in acanthomatous ameloblastomas, AOTs and ameloblastic carcinomas, and in the linings of KCOTs suggests that the HGF/c-met interaction may have an influence on squamous differentiation in these odontogenic tumors.