RET gene rearrangements and somatic mutations are common genetic events in thyroid cancer and are closely associated with tumor development and exhibit characteristic distributions: approximately 25% of hereditary MTC cases harbor RET germline activating mutations (associated with MEN 2A/B), and approximately 45% of sporadic MTC cases carry RET somatic mutations. The gene discussed is RET; the disease is medullary thyroid gland carcinoma.