MTOR and neoplasm: Everolimus is an mTOR inhibitor that plays a role in the tumorigenesis and progression of NENs, while sunitinib is a multi-targeted tyrosine kinase inhibitor (TKI) that blocks the activation of VEGFRs 1–3 (vascular endothelial growth factor receptor 1–3), PDGFR-α and -β (platelet-derived growth factors-α and -β), KIT (stem-cell growth factor receptor), FLT3 (fms-related tyrosine kinase 3), RET and CSF1R (colony-stimulating factor receptor 1), resulting in antiangiogenic and antitumor activity against a broad range of neoplasms.