Expression of transforming growth factor-alpha (TGF-alpha) in cholesteatoma.
ABSTRACT This 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-alpha. The subjects of this study were patients who had undergone operation for middle ear cholesteatoma. Skins of the bone region of the external ear canal (normal skin) of the same patients were used as the negative control. The mode of expression of TGF-alpha was studied by immunohistochemistry and in situ hybridization. In the immunohistochemical study, there were no conspicuous differences observed between cholesteatoma tissues and normal skin. After in situ hybridization, expression of TGF-alpha 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 TGF-alpha mRNA was observed up to layers superior to the basal cell layer. The expression of TGF-alpha mRNA is greatly affected by subepithelial connective tissue, strongly suggesting involvement of paracrine regulation in proliferation of cholesteatoma epithelium.
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ABSTRACT: The expression and localization of placenta growth factor (PlGF) within cholesteatoma were defined. The authors propose that PlGF is an angiogenic growth factor in cholesteatoma, and participates in the neoangiogenesis of cholesteatoma. Middle ear cholesteatoma is characterized by the presence of a keratinizing squamous epithelium with hyperproliferative features. Such growth can only be supported by abundant blood vessels. Because proliferating tissues require an enhanced blood supply, angiogenesis appears to be a prerequisite for the expansion of cholesteatoma. This study aimed to analyze the presence of PlGF as an angiogenic growth factor in human cholesteatoma. Tissue samples from human cholesteatoma and normal auditory meatal skin were obtained from patients during surgery for cholesteatoma of the middle ear. PlGF mRNA expression was quantified by real-time reverse transcriptase-polymerase chain reaction (RT-PCR). PlGF was localized by immunohistochemical staining. Western blotting was used for detection of PlGF protein. Expression of PlGF mRNA was significantly elevated in the epithelium of cholesteatoma compared with normal auditory meatal skin. PlGF was detected on cholesteatoma by Western blotting. PlGF was detected in the suprabasal layer of cholesteatoma using immunohistochemical study, but was not detected in normal auditory meatal skin.Acta Oto-Laryngologica 10/2006; 126(9):900-4. · 1.11 Impact Factor