Calcitonin is a marker of thyroid

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.