Histopathological and immunohistochemical studies of oral leukoplakia. Special reference to the expression of transforming growth factor-.ALPHA. and epidermal growth factor receptor.

Sixty-four cases of oral leukoplakia were examined immunohistochemically by the ABC method with monoclonal antibodies to transforming growth factor alpha (TGF-α) and epidermal growth factor receptor (EGF-R) to study the correlation between epithelial dysplasia of epithelial cells and localization.Method: Specimens removed surgically and by biopsy were fixed according to convevtional methods, embedded in paraffin, thinly sliced, and H-E stained for histopathological study. The specimens were stained immunohistochemically by the ABC method with monoclonal antibodies to observe the localization of TGF-α and EGF-R.Results: The localization of TGF-α was often observed evenly in all layers of the epidermis in both normal mucosa and leukoplakia without epithelial dysplasia, whereas in leukoplakia with epithelial dysplasia it was often found irregularly in all layers of the epithelium except for the basal layer. In nomal mucosa and leukoplakia, the localization of EGF-R was frequently found in all layers of the epithelium except for the basal layer.We consider immunohistochemical studies of the localization of TGF-α to be useful for the evaluation of epithelial dysplasia in leukoplakia.