GATA4 and head and neck squamous cell carcinoma: The differentially methylated genes in HPV-associated HNSCC are involved in cell-cycle regulation (CCNA1 [34,77,78]), apoptosis (RASSF1 [79]), cellular adhesion (cadherin genes, such as CDH1, CDH8, CDH11, CDH13, CDH15, CDH18, CDH19, and CDH23 [78,80,81,82,83], and ITGA4 [80,84]), cellular migration (TIMP3 [82]), differentiation (CTNNA2, RXRG, and GATA4 [80,85]), and G protein-coupled receptor (GPCR) genes (GHSR, CASR, NMUR1, PTGDR1, PTGDR2, and PTGIR [80,86,87]) (Table 1).