RET fusions are another class of mutations that have been detected in 5–10% of thyroid cancers (excluding medullary thyroid cancers), and a durable response was achieved in a patient with ATC who received selpercatinib, a selective RET inhibitor, as part of the LIBRETTO-001 phase 1/2 pan-tumour study (10, 11). This evidence concerns the gene RET and medullary thyroid gland carcinoma.