FGFR1 and differentiated thyroid carcinoma: Lenvatinib is an oral multi-target kinase inhibitor (MKI) targeting vascular endothelial growth factor receptors 1–3 (VEGFR1–3), fibroblast growth factor receptors 1–4 (FGFR-1–4), platelet-derived growth factor receptor α (PDGFRα), RET and KIT proto-oncogenes, used as a monotherapy for the treatment of progressive radioiodine-refractory differentiated thyroid cancer (RAI-R-DTC) which has allowed to increase the survival of these patients (2, 3).