Studies have shown that the dedifferentiation of DTC is progressively achieved by mutations in several genes and alterations, and the most important genes include BRAF, RAS, RET, TERT, etc., which promote the progression of thyroid cancer cells from DTC to PDTC or even ATC through activation of the signaling pathways such as MAPK and PI3K/AKT, respectively. The gene discussed is RET; the disease is thyroid cancer.