This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thyroid Malignancies, Subject name: Surgery
Tumor marker for medullary carcinoma of thyroid is: 
Select and explain. 
A. Albumin, B. TSH, C. Thyroglobulin, D. Calcitonin
D: Calcitonin
Answer: D: Calcitonin 
Explanation: Ans. (d) CalcitoninRef: Bailey and Love 26th ed. ch. 51 / 764* Medullary thyroid cancer is a rare form of thyroid cancer and accounts for 3 to 10% of all thyroid cancers. It grows from specialized thyroid cells called parafollicular cells.* Parafollicular cells-C-cells; specialized thyroid cells that secrete calcitonin and play a major role in diagnosis of medullary thyroid cancer.