Calcitonin is a marker of thyroid: (A) Papillary carcinoma, (B) Medullary carcinoma, (C) Anaplstic carcinoma, (D) Adenocarcinoma
Answer is B. Refer Robbins page no Pg 1030 Medullary Thyroid Carcinomas. Familial medullary thyroid carcinomas occur in multiple endocrine neoplasia type 2 (MEN-2, see later) and are associated with germline RET mutations that lead to constitutive activation of the recep- tor. RET mutations are also seen in approximately one half of nonfamilial (sporadic) medullary thyroid cancers. Chromosomal rearrangements involving RET, such as the RET/PTC translocations repoed in papillary cancers, are not seen in medullary carcinomas.