Immunoexpression of transforming growth factor beta in desmoplastic ameloblastoma

Desmoplastic ameloblastoma (DA) is an unusual subtype of ameloblastoma hist ologically characterized by the pronounced collagenized stroma. In the pres ent study, the immunolocalization of transforming growth factor beta (TGF-b eta), one of the most potent local factors for modulating extracellular mat rix formation, was observed in DA in order to study its participation in th e stromal desmoplasia. Seven cases of DA, including a "hybrid" lesion, were studied together with ten cases of ordinary follicular and plexiform amelo blastomas as the control. In contrast to ordinary ameloblastomas, marked im munoexpression was observed in all DAs but one. In the "hybrid" lesion, TGF -beta was not expressed in the area of follicular ameloblastoma but in that of DA. These results show that TGF-beta produced by tumor cells of DA play s a part in the desmoplastic matrix formation.