Keratinocyte growth factor receptor (KGF-R) in cholesteatoma tissue

Distribution of the receptor for epidermal growth factor (EGF-R) and of the receptor for the keratinocyte growth factor (KGF-R) in cholesteatoma was found to differ in analogy with other epithelial tissues and accordingly to epidermal differentiation and intensity of paracrine stimulation. Moreover, both EGF-R and KGF-R expression was increased, suggesting a fair correlation with aggressiveness and recurrence rate of this pathology.

To obtain information on the biological behaviour of cholesteatoma by assessing the expression and localization of EGF-R and KGF-R and correlating their tissue distribution with that of cytokeratins as a marker of differentiation.

Cholesteatoma tissue was taken during tympanoplasty surgery and processed for indirect immunofluorescence. Murine monoclonal antibodies were tested for the different growth factor receptors and pancytokeratins analysed. Fluorescence intensity signal was measured on randomly captured digital images, using FISH 2000/HI software, with a pseudocolours generation module.

EGF-R was mostly expressed at the level of keratinocytes of the basal layer, while KGF-R signal was mainly distributed on the spinous and granular suprabasal layers that were also highly positive for cytokeratins. Significant correlation between the immunofluorescence signals was found for KGF-R and cytokeratins only, demonstrating that KGF-R expression is increased in more differentiated areas of the cholesteatoma tissue, while EGF-R is associated with proliferative and migratory portions of the lesion.