Expression of inducible nitric oxide synthase and vascular endothelial growth factor in ameloblastoma

The purposes of this study were to determine the correlation between the expression of inducible nitric oxide synthase (iNOS) and vascular endothelial growth factor (VEGF) in ameloblastoma and to examine the relationships of this expression to angiogenesis and the clinical and biological behaviors of the tumor. Immunohistochemical staining with streptavidin peroxidase was used to analyze iNOS and VEGF expression, and CD34 was used to evaluate microvascular density (MVD) in 35 ameloblastomas (24 primary tumors and 11 recurrences) and 5 malignant ameloblastomas. Ten odontogenic keratocysts (OKCs) served as controls. On relational analysis, positive and VEGF expression and MVD counts increased in this order: OKCs, primary ameloblastoma, recurrent ameloblastoma, and malignant ameloblastoma. Differences between the ameloblastomas and OKCs were significant (P < 0.05). Among ameloblastomas, MVD counts increased with increasing expression of iNOS and VEGF (P < 0.05), and iNOS expression and VEGF expression were positively correlated (r = 0.66, P < 0.05). Inducible nitric oxide synthase expression and VEGF expression may be closely related to the angiogenesis and invasive biological behavior of ameloblastomas.