The expression of the following oncogene is associated with a high incidence of medullary carcinoma of thyroid:

- RET proto-oncogene is mutation is associated with medullary carcinoma of thyroid - RET proto-oncogene is mutated in MEN-2A & 2B syndromes, hence these are also associated with medullary carcinoma of thyroid. - Prophylactic thyroidectomy is indicated in pt with family history of RET mutation