Fig. 1

HER2 signaling pathway. HER2 and other EGFR family members as receptor tyrosine kinases positioned on the cell membrane can responds to various ligands. Phosphorylation of the tyrosine kinase domain in the cytoplasm instigates subsequent oncogenic signaling axes, such as PI3K/AKT pathway and Ras/MAPK pathway. Human epidermal growth factor receptor 2 (HER2), Phosphoinositide 3-kinase (PI3K), Mitogen-activated protein kinase (MAPK), Mammalian target of rapamycin complex (mTORC), BCL2 associated agonist of cell death (BAD), Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), inhibitor of nuclear factor kappa (IκBα), B-cell lymphoma-extra-large (Bcl-xL), Mitogen-activated protein kinase (MAP2K or MEK), MEK kinase (MEKK), Stress activated protein kinases (SAPKs), cAMP-response element binding protein (CREB), Cyclooxygenase-2 (COX-2), Hypoxia-inducible factor-1 (HIF-1), Protein kinase C (PKC), Phospholipase C gamma (PLCγ), Diacyl glycerol (DAG), Inositol 1,4,5-trisphosphate (IP3), Vascular endothelial growth factor (VEGF), Epidermal growth factor receptor (EGFR)