Sunitinib is a multi-kinase inhibitor of VEGFR, PDGFR, fms-related receptor tyrosine kinase 1 (FLT1), FLT1/kinase insert domain receptor (KDR), FLT3 and Ret Proto-Oncogene (RET) kinases with no encouraging results in patients with GBM [70]. Here, RET is linked to glioblastoma.