RET and thyroid cancer: MTC represents 1–2% of thyroid cancers, making it the third most common thyroid cancer.2 Of the total number of cases, 25% are hereditary, whereas 75% are sporadic.3 The hereditary form is part of the multiple endocrine neoplasia type 2 (MEN-2) syndromes, which are associated strongly with RET proto-oncogene mutation.4