Objective: To understand the interaction between cholesteatoma epithelium and subepithelial connective tissue as a paracrine regulation by keratinocyte growth factor.
Design: Preparation of a specific DNA probe from human fetal fibroblast and detection of localization of keratinocyte growth factor messenger RNA in subepithelial granulation tissue of middle-ear cholesteatoma by a nonradioactive in situ hybridization method.
Participants: The cholesteatoma specimens were excised from 12 patients during surgery. Normal skin specimens collected from the external ear canal of six patients were used as controls.
Results: Signals specific for keratinocyte growth factor messenger RNA were not expressed in the normal skin of the external ear canal, but were observed in fibroblasts of subepithelial connective tissue of cholesteatoma specimens. Signals were observed only in specimens collected from patients whose subepithelial connective tissue was thick and proliferated and whose inflammation was strong.
Conclusions: A paracrine regulation mechanism involving keratinocyte growth factor may exist for proliferation of epithelium of cholesteatoma. The subepithelial connective tissue of cholesteatoma may play an important role in the proliferation and development of the cholesteatoma, especially under inflammatory conditions.