RET and medullary thyroid gland carcinoma: However, if we consider that the percentage of MTC patients with lymph-node metastasis and/or distant metastasis in big series of MTC is around 45.1–53% and 10–11.4%, respectively [19,20,21], our findings demonstrate that, even in already affected GCs, the RET genetic screening can anticipate the diagnosis when the MTC is still clinically silent.