RET and thyroid tumor: Inspired by their work, Santoro et al. conducted a study on 286 thyroid tumors (177 PTC, 37 FTC, 15 ATC, 18 MTC, 34 benign thyroid nodules and 5 cases of squamous cell carcinoma and sarcomatoid carcinoma of the thyroid), and found RET aberrations exclusively in 19% of PTC (33/177) [17].