Expression of transforming growth factor-α (TGF-α) in cholesteatoma

Abstract

AbstractThis study aims at elucidating the role of cytokines in the mechanism of proliferation of cholesteatoma epithelium by investigating the mode of expression of epidermal growth factors, such as TGF-α. The subjects of this study were patients who had undergone operation for middle ear cholesteatoma. Skins of the bone region of the externalear canal (normal skin) of the same patients were used as the negative control. The mode of expression of TGF-α was studied by immunohistochemistry andin situhybridization. In the immunohistochemical study, there were no conspicuous differences observed between cholesteatoma tissues and normal skin. Afterin situhybridization, expression of TGF-α mRNA was mainly observed in the epidermal basal cell layer in the normal skin, while in the cholesteatoma epidermis with severe inflammatory cell infiltration, expression of TFG-α mRNA was observed up to layers superior to the basal cell layer. The expression of TGF-α mRNA is greatly affected by subepithelial connective tissue, strongly suggesting involvement of paracrine regulation in proliferation of cholesteatomaepithelium.