Active key proteins in the above mentioned pathways, with an important role in transmitting these intracellular signals, such as EGFR1 (epidermal growth factor receptor 1), VEGFR2 (endothelial vascular endothelial growth factor receptor 2), PI3Kα, AKT, MEK1 (MAP kinase/ERK kinase 1), ERK2 (extracellular regulated signaling kinase 2) and PDK1 (phospholipid-dependent kinase 1) are currently extensively studied as targets for novel drug discovery in the treatment of various types of cancer. Here, KDR is linked to cancer.