Immunotherapy using immune checkpoint inhibitors showed therapeutic effect in sparse cases,[5, 6, 7, 8] so the net benefit needs to be carefully characterized.[9] Unlike well‐differentiated thyroid cancers, ATCs are virtually refractory to radioiodine therapy due to loss of sodium iodide symporter (NIS). This evidence concerns the gene SLC5A5 and Ehlers-Danlos syndrome, musculocontractural type.