EGFR and cholesteatoma: Since HSP27 could be phosphorylated in response to Vascular endothelial growth factor (VEGF) via the p38 MAPK/MAPKAPK2 pathway and triggered by the association of Epidermal growth factor (EGF) and EGF receptors (EGFR) via the Ras/Raf/ERK1/2 MAPK pathway during the progression of cholesteatoma [23], the regulation of these signaling molecules was examined.