ODONTOGENIC MYXOMA - CHARACTERIZATION OF THE EXTRACELLULAR-MATRIX (ECM) OF THE TUMOR STROMA

In order to elucidate the origin of the odontogenic myxoma, the compos ition and the structural organisation of the extracellular matrix (ECM ) of this tumour were characterised. Collagen type I, VI, procollagen type III, undulin, tenascin and fibronectin were demonstrated in biops y material of 4 cases by polyclonal antibodies. The tumour stroma show ed a pronounced reaction for collagen type I. Fibroblasts displayed an intense intracytoplasmatic reaction for procollagen type III, and col lagen type I was not found in the fibroblasts of the adjacent normal o ral mucosa. In contrast to the surrounding connective tissue, label fo r collagen type VI was weak, as was the reaction for fibronectin and t enascin. Undulin was almost undetectable. The immunohistochemical resu lts suggest that the odontogenic myxoma is characterised by an as yet unobserved structural organisation of ECM proteins, a secretion defect of fibrillar collagens type I and III with no resemblance to physiolo gical tooth development.