Keratinocyte growth factor and receptor mRNA expression in cholesteatoma of the middle ear

Keratinocyte growth factor (KGF) is synthesized and secreted exclusively by stromal cells in epithelialized organs, and specifically promotes proliferation of cells of epithelial origin, including keratinocytes. Cholesteatoma is a proliferative form of keratinocyte dysregulation with aggressive growth that often leads to destruction of adjacent bone. We examined the expression of KGF, closely related peptides and their receptors in the development of cholesteatoma by comparing cholesteatoma with normal ear skin using the reverse transcription-polymerase chain reaction (RT-PCR) followed by Southern blot analysis. All surgical specimens of cholesteatoma and most normal ear skin samples expressed detectable levels of KGF and KGF receptor (KGFR). Semiquantitative RT-PCR using beta-actin mRNA as an internal standard revealed significantly higher expression of KGF mRNA in cholesteatoma than in normal skin, while no significant difference in KGFR mRNA expression was noted between cholesteatoma tissue and normal skin. These results suggest that excessive KGF synthesis may contribute to the hyperproliferative state in cholesteatoma.