Immunohistochemical and ultrastructural investigation of epithelial-mesenchymal interactions in odontogenic epithelial lesions.

Etiology of many of the odontogenic lesions is unknown and theirpathogenesis have been widely studied. Some odontogenic lesions presentsrecurrent and aggressive behavior, whilst others are known to have ?innocent? clinicalprognosis. Basement membrane (BM) is a mechanic barrier formed by bothepithelium and connective tissue in order to separate them. BM also plays major rolein important cellular events such as differentiation, adhesion and migration. BMregulates epithelio-mesenchymal interactions for the development of epithelial tissue.The aim of this study was to expose the interaction between theodontogenic epithelium and the connective tissue in the formation of odontogeniclesions. For this purpose we investigated the interaction between the epithelium andadjacent BM.This study included 81 odontogenic lesions archived in Gazi UniversityFaculty of Dentistry?s Oral Pathology Department. Histological slides were stainedwith PCNA, laminin, tenascin and integrin antibody. Fresh tissues of odontogeniclesions, supplied by the Oral and Maxillofacial Surgery department, were evaluatedon transmission electron microscope (TEM)TEM showed an intact BM in all lesions. In overall ameloblastoma,adenomatoid odontogenic tumor (AOT) and keratocystic odontogenic tumour had themost pronounced proliferative epithelium. The BM showed continuous laminin andtenascin expresion. Except AOT, all cases showed positive reactivity for integrin onthe basal cell layer. Therefore it can be hypothesized that BM originates fromodontogenic epithelium and plays a crucial role for epithelial organisation anddevelopment of all lesions. It can also be suggested that laminin, integrin andtenascin are the affector molecules for epithelial connective tissue interaction.Key Words: odontogenic lesions, proliferative index, adhesion molecules, basementmembrane