RET and medullary thyroid gland carcinoma: The first TKI approved by the Food and Drug Administration (FDA) on April 2011 for the treatment of advanced and progressive and/or symptomatic MTC was vandetanib, which blocks signaling of epidermal growth factor receptor (EGFR), of vascular endothelial growth factor receptor-2 (VEGFR2), and of rearranged during transfection (RET).