TCF21 and head and neck cancer: Likewise, in other human cancer types, such as gastric cancer, colorectal cancer, melanoma, head and neck cancer, and non‐small‐cell lung carcinoma, hypermethylation is described to be the predominant mechanism for TCF21 downregulation (Arab et al., 2011; Dai et al., 2016; Smith et al., 2006; Yang et al., 2015).