The receptor, tyrosine kinase c-Ret, has been found to be an oncogenic mutation in patients with multiple endocrine tumors and cancer syndromes with familial medullary thyroid carcinoma, and DOK5 can be directly associated with Y1062 of c-Ret, thereby enhancing the effect of c-Ret [3]. This evidence concerns the gene DOK5 and multiple endocrine neoplasia type 2.