EGFR and neoplasm: Signaling pathways associated with tumor resistance include epidermal growth factor receptor (EGFR), renin-angiotensin system (Ras), phosphatidylinositol-3 kinase/protein kinase B (PI3K/Akt), Wnt, Notch, transforming growth factor-β (TGF-β) and their specific natural product signaling pathway inhibitors.