Epithelial cell rests of Malassez bind epidermal growth factor intensely

The binding of 125 I‐labelled epidermal growth factor (EGF) in the dental follicle was studied by autoradiography. The follicle of a surgically removed impacted premolar was cut into small pieces which were incubated in the presence of 125 I‐EGF. Very intense binding was localized in the epithelial cell rests of Malassez, whereas only background labelling was seen in fibroblastic cells. EGF is a hormone‐like molecule which is believed to exert its effects locally and through binding to a specific cell surface receptor. The number of EGF receptors in many cells – e.g., basal epidermal cells ‐ is related to cell proliferation. The present observations indicate that EGF receptors are expressed in high amounts by the cells of the epithelial rests, and that these cells are thus potentially responsive to the actions of EGF. It can be speculated that activation of the epithelial rest cells in various pathologic conditions is associated with a local rise in the tissue level of EGF.