Immunohistochemical detection of platelet-derived endothelial cell growth factor/thymidine phosphorylase and angiopoietins in ameloblastic tumors

Abstract

To evaluate the roles of angiogenic factors in the development and progression of odontogenic tumors, expression of platelet-derived endothelial cell growth factor/thymidine phosphorylase (PD-ECGF/TP) and of angiopoietins in ameloblastic tumors as well as in tooth germs.Tissue specimens of 11 tooth germs, 44 ameloblastomas, and five malignant ameloblastic tumors were examined immunohistochemically with the use of antibodies against PD-ECGF/TP and angiopoietin-1 and -2.Immunohistochemical reactivity for PD-ECGF/TP was detected in mesenchymal cells in tooth germs and stromal cells in ameloblastic tumors, and the level of immunoreactivity for PD-ECGF/TP was significantly higher in ameloblastomas than in tooth germs. Granular cell ameloblastomas showed PD-ECGF/TP reactivity in granular neoplastic cells as well as in stromal cells. Immunoreactivity for angiopoietin-1 and -2 was detected predominantly in odontogenic epithelial cells near the basement membrane in tooth germs and in benign and malignant ameloblastic tumors. Malignant ameloblastic tumors had decreased angiopoietin-1 reactivity and ameloblastic carcinomas had increased angiopoietin-2 reactivity as compared with the respective levels in tooth germs and ameloblastomas. Immunohistochemical reactivity for angiopoietin-2 was slightly higher in follicular ameloblastomas than in plexiform ameloblastomas.Expression of PD-ECGF/TP and angiopoietin-1 and -2 in tooth germs and ameloblastic tumors suggests that these angiogenic factors participate in tooth development and odontogenic tumor progression by regulating angiogenesis. Altered expression of PD-ECGF/TP and angiopoietins in ameloblastic tumors may be involved in oncogenesis, malignant potential, and tumor cell differentiation.