Expression of heat shock protein 27 in odontogenic cysts

HSP27 belongs to the Heat shock protein (HSP) family, which exerts essential functions during the cell cycle under physiological conditions and prevents the stress-induced cellular damage. During the cell development, Hsp27 seem to play a crucial role at different stages, associated with cell proliferation, differentiation and death. Moreover, it seems involved in the balance between differentiation and apoptosis, also during the formation of calcified tissue. The aim of this study was to investigate the expression of HSP27 in odontogenic cysts and its possible biological role. Histological sections of epithelial odontogenic cysts (10 radicular cysts, 8 dentigerous cysts, 16 odontogenic keratocysts) were analyzed for HSP27 expression by immunohistochemistry. All odontogenic cysts were positive for HSP27, although with remarkable differences in the immunostaining pattern according to cyst types. Both proliferating epithelial cell rests and radicular cysts shared an overexpression of HSP27 with concomitant presence of local intraepithelial or subepithelial inflammatory cells. In odontogenic cysts epithelial cells immunolabelling was mainly cytoplasmatic. HSP27 expression may play several roles in the pathogenesis of periapical dental lesions including the induction of epithelial cell rests migration and the increased resistance both to necrosis and apoptosis.