HGF and medullary thyroid gland carcinoma: The widespread alterations of the HGF-MET axis boosted the search for their inhibitors in the past decade, which led to FDA approval of two tyrosine kinase inhibitors (TKIs), Crizotinib for non-small cell lung cancer and Cabozantinib for renal cell cancer and medullary thyroid cancer, both capable of inhibiting the altered MET protein activity (25).