Expression of PLC-r1 in Human Middle Ear Cholesteatoma

Abstract

BACKGROUND: EGF and TGF-gamma are believed to mediate their pleiotrophic actions by binding to and activating cell surface receptors with an intrinsic protein-tyrosine kinase. Protein-tyrosine kinase phosphorylation has been considered involved in intrinsic signal transduction, proliferation and transformation of the cells. Phospholipase C-gamma1 is well characterized substrate for tyrosine kinase. OBJECTIVE: The purpose of this study is to elucidate the distribution of PLC-gamma1 in normal meatal skin and cholesteatoma matrix. MATERIALS AND METHODS: 8 cholesteatoma specimens were obtained from operated patients for immunohistochemistry and western blot analysis. RESULTS: On immunohistochemistry, PLC-gamma1 was detected only in basal layer of the deep meatal skin, but was readily detectable in both the basal and suprabasal layer in cholesteatoma matrix. By western blot analysis, considerable higher levels of PLC-gamma1 protein were detectable in cholesteatoma matrix compared with the deep meatal skin. CONCLUSION: Overexpression of PLC-gamma1 in cholesteatoma suggests a possible derangement of enhanced growth signal transduction in keratinocytes.