About Medullary Thyroid Cancer (MTC)

• Medullary thyroid cancer (MTC) accounts for 5-10% of all thyroid cancers.

• Medullary thyroid cancer is a rare type of thyroid cancer that comes from a group of thyroid cells that are called parafollicular C-cells.

• These C-cells are different from the cells in differentiated thyroid cancer in the sense that they do not make thyroid hormone, they are not responsive to TSH stimulation, and they make a different protein called calcitonin.

• There are two types of medullary thyroid cancer: sporadic and familial.

• Sporadic medullary thyroid cancer usually occurs only in patients ages 20 and over.

• Familial (inherited) medullary thyroid cancer can appear at any time from infancy to adulthood. This type of medullary thyroid cancer often comes as part of a disease called Multiple Endocrine Neoplasia type 2 (MEN2), although it can also occur by itself in familial medullary thyroid carcinoma (FMTC).

• In children and adolescents, MTC is almost always the familial form, meaning that it is due to a specific mutation (defect) in the DNA of the cells of the body. This mutation occurs in a gene called the RET proto-oncogene.