Abstract. Background: Tumor necrosis factor-relatedapoptosis-inducing ligand (TRAIL) is a recently identified death factor that acts as a potent apoptosis inducer in ameloblastomas. Materials and Methods: The expression of TRAIL and its receptors (TRAIL-R), and the location of TRAIL and its receptors (TRAIL-R), and the location ofameloblastomausing immunohistochemistry and an in situ DNA nick-end labeling method. The proliferative activity of ameloblastomas was analyzed by determining the Ki-67 labeling index.Results: TRAIL and TRAIL-R were diffusely expressed ameloblastomas, without clear correlation with the locationof apoptotic cells. Apoptosis and proliferation were opposite in the peripheral and central components of the ameloblastomas. In some ameloblastoma variants apoptosis, and proliferation seemed to modify in the same direction.Conclusion: TRAIL and its receptors might be involved in neoplastic transformation of odontogenic epithelium and might suggest some intrinsic regula
