PTEN and thyroid cancer: Hypermethylation can lead to the silencing of tumor suppressor genes, leading to carcinogenesis; common examples in thyroid cancer include Ras association domain family 1; isoform A (RASSF1A); cyclin-dependent kinase inhibitor 2A (CDKN2A or P16INK4A); death-associated protein kinase1 (DAPK); tissue inhibitor of metalloproteinase-3 (TIMP3); SLC5A8; SLC5A5; thyroid stimulating hormone receptor (TSHR); PTEN; retinoic acid receptor β2 (RARβ2); RAP1 GTPase activating protein (RAP1GAP); and fibroblast growth factor receptor (FGFR) 2 [73,74,75,76].