The RET proto-oncogene was discovered by Takahashi et al. in 1985.17 The RET proto-oncogene encodes a tyrosine kinase transmembrane receptor and is mutated in virtually all hereditary MTC and in around 50% of sporadic MTC.18 The M918T mutation is present in 85% of somatic RET mutations and has been associated with a poorer prognosis and more aggressive clinical course.19 A mutated RET leads to a constitutively active protein receptor with constant growth signals to the cell. Here, RET is linked to medullary thyroid gland carcinoma.