This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pathology, Subject name: Pathology
Calcitonin is a marker of - 
Select and explain. 
A. Prostate cancer, B. Medullary carcinoma of thyroid, C. Pheochromocytoma, D. Pancreatic cancer
B: Medullary carcinoma of thyroid
Answer: B: Medullary carcinoma of thyroid 
Explanation: Harshmohan textbook of pathology 7th edition. medulla carcinoma is a less frequent type derived from para follicular or C cells present in the thyroid. Like normal C cells tumor cells of medullary carcinoma secrete calcitonin the hypo calcimic hormone. So calcitonin is an impoant tumor marker of medullary carcinoma of thyroid. .