In patients with thyroid cancer, TERT promoter mutations are classified as a late event and are found in more aggressive thyroid cancers, being more common in patients with poorly differentiated or anaplastic cancer (up to ~70% of cases) than those with well-differentiated PTC and follicular thyroid carcinoma (FTC) (~10–20%). The gene discussed is TERT; the disease is thyroid cancer, nonmedullary, 2.