Over the past 5 years, patients with progressive radioactive iodine-refractory 
thyroid cancer have responded to "targeted" multikinase inhibitors, which 
inhibit angiogenesis and not the tumor cell. Here, selumetinib targets the 
mitogen-activated protein kinase pathway in papillary thyroid carcinoma and 
shows limited single-agent activity in the patients with tumors that harbor the 
(V600E)BRAF mutation.