Other tumor suppressor genes, such as p16 (INK4A), TSHR, MGMT, DAPK, ESR1, ESR2, RARβ, PTEN, CD26, SLC5A8, and UCHL1, are always methylated in ATC, in contrast to differentiated thyroid cancer [122]. Here, DPP4 is linked to thyroid gland carcinoma.