The European Society of Medical Oncology (ESMO) and National Comprehensive Cancer Network (NCCN) suggest that germline testing for RET mutations is indicated for patients with a family history of RET gene mutations or hereditary MTC, patients with clinical features suspicious for multiple endocrine neoplasia type II, and newly diagnosed patients with clinically apparent sporadic MTC. Here, RET is linked to multiple endocrine neoplasia type 2A.