LOCALIZATION OF TRANSFORMING GROWTH FACTOR-BETA-EXPRESSING CELLS AND COMPARISON WITH MAJOR EXTRACELLULAR COMPONENTS IN AURAL CHOLESTEATOMA

Transforming growth factor-beta (TGF-beta) plays an important role in the regulation of extracellular matrix (ECM) deposition by stimulating the synthesis of individual matrix proteins like tenascin and fibrone ctin. Cholesteatoma shows significant changes in the ECM, supporting t he view of a disturbed cell-matrix interaction. The purpose of our pre sent study was to evaluate the distribution of TGF-beta in comparison to the deposition of tenascin, fibronectin, and collagen as major comp onents of the ECM in cholesteatoma (n = 12) by means of histochemistry and immunohistochemistry. We found TGF-beta in lymphocytes and fibroh istiocytes in the stroma of 7 cholesteatomas. In corresponding section s, a marked expression of tenascin and fibronectin was seen manifestin g as a continuous band along the epidermal-stromal junction, extending to the deeper stroma. In addition, in those cases of TGF-beta express ion, beginning collagen fibril formation was seen in adjacent deeper s troma layers, indicating beginning stromal fibrosis. These results sug gest that TGF-beta may be involved in the stimulation of the synthesis of tenascin, fibronectin, and collagen. Furthermore, the enhanced exp ression of tenascin and fibronectin provides evidence for a deregulate d cell-matrix interaction in cholesteatoma associated with the enhance d proliferative process of cholesteatoma formation.