Molecular mechanisms targeting drug-resistance and metastasis in colorectal cancer: Updates and beyond

Figure 3 Mechanisms of resistance to targeted therapy and strategies to overcome resistance in colorectal cancer. A: Resistance mechanisms; B: Strategies to overcome resistance. EGFR: Epidermal growth factor receptor; HER2: Human epidermal growth factor receptor 2; VEGF: Vascular endothelial growth factor; MEK: Mitogen-activated extracellular signal-regulated kinase; MAP2K1: Mitogen-Activated Protein Kinase 1; PI3KCA: Phosphoinositide 3-kinases catalytic subunit alpha; MAP2K1: Mitogen-activated protein kinase 1; HGF: Hepatocyte growth factor; MET: Mesenchymal epithelial transition; ERBB2: Erb-B2 Receptor Tyrosine Kinase 2; TME: Tumor microenvironment; FGF: Fibroblast growth factor; PDGF: Platelet-derived growth factor; PD-1: Programmed death-1; PD-L1: Programmed death ligand-1; CTLA-4: cytotoxic T lymphocyte-associated antigen 4.