The BRAF T1799A mutation is a common gene mutation in thyroid cancer, melanoma and colon cancer1, 2, 3, 4; Molecular studies have found the BRAF T1799A mutation in approximately 45% of PTC and 25% of apparently PTC‐derived anaplastic thyroid cancers, but not in follicular thyroid cancer (FTC) and benign thyroid tumours.5 The gene discussed is BRAF; the disease is thyroid gland undifferentiated (anaplastic) carcinoma.