CEACAM5 and medullary thyroid gland carcinoma: Several studies have indicated that increased CEA and calcitonin levels were associated with larger tumors and more metastatic LNs, suggesting a larger extent of surgery.26,27 These biochemical parameters also had the potential for predicting MTC recurrence.28RET gene mutation is an important molecular event during the development and progression of MTC and has been implicated in LNM of MTC and disease persistence following surgery.29 In future updates of the AJCC staging system for MTC, the inclusion of key biochemical and genetic considerations will be an important direction.