KRAS and medullary thyroid gland carcinoma: Activating RAS family gene point mutations (mainly H-RAS and K-RAS) which are mutually exclusive of RET mutations and are associated with a better prognosis, result in about 28% of cases of sporadic MTC, and BRAF Val600Glu (also known as V600E) mutations are very occasionally also found in MTC (19); for a portion of cases, the oncogenic driver has not been identified (25).