TGFA and oral lichen planus: Similar to our results, Kumagai et al. (21) observed EGFR overexpression in all OLP samples, and additionally they observed overexpression of EGFR ligands (amphireguline, epireguline y HB-EGF [Heparin-binding-EGF like growth factor]) and decreased expression of the ligands EGF and TGF-alpha.