Selpercatinib (29) is a rearranged during transfection (RET) receptor tyrosine kinase inhibitor approved for cancers harboring RET mutations (metastatic RET fusion-positive NSCLC, advanced/metastatic RET-altered medullary thyroid cancer and papillary thyroid carcinoma). The gene discussed is RET; the disease is medullary thyroid gland carcinoma.