EGFR and fibrosis: Furthermore, Studies have suggested that EGFR signaling can promote renal and vascular fibrosis through a MAPK-mediated mechanism [20], and the overexpression of dominant negative EGFR or use of AG1478 (AG), an EGFR tyrosine kinase inhibitor, was observed to drastically reduce TGF-β and fibronectin expression in cultured cells [21].