WEE1 and neoplasm: Regorafenib is a multiple protein kinase inhibitor that target angiogenesis (the VEGFR 1–3 and the angiopoietin 1 receptor TIE2) more intensively than sorafenib, tumor cells (especially the oncogenic kinases Kinase Insert Domain Receptor (KIT) and Rearranged during Transfection and the intracellular kinases Raf), and fibroblast growth factor receptors, in a more targeted manner than sorafenib.[25] Regorafenib has only 1 additional fluorine atom compared to sorafenib, resulting in a 3-fold increase in its bioavailability.