This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology and breast, Subject name: Surgery
[{'content': 'All of the following are true about medullary carcinoma of thyroid except \nSelect and explain. \nA. It is tumour arising from C cells derived from the neural crest, B. Secrete high levels of calcitonin, C. It is not dependent on TSH, D. Most cases are familial', 'role': 'user'}, {'content': 'Answer: D \nExplanation: MEDULLARY CARCINOMA It is an uncommon type it arises from the parafollicular C cells which is derived from ultimobranchial body (neural crest) blood level of calcitonin is a tumour marker it is not dependant on TSH Most cases are sporadic and a small amount is familial ref ;(page no;486) 5th edition of SRB&;S Manual of SURGERY', 'role': 'assistant'}]