FLT4 and thyroid cancer: Lenvatinib is being investigated for treatment of differentiated thyroid cancer and is a multi-targeted TKI of the VEGFR1-VEGFR3, fibroblast growth factor receptor 1 through 4 (FGFR1-FGFR4), platelet-derived growth factor receptor α (PDGFRα), the rearranged during transfection (RET) proto-oncogene, and v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog signaling networks [4].