DAPK1 and head and neck squamous cell carcinoma: A meta-analysis of eighteen studies confirmed that methylation of the DAPK promoter is over fourfold higher in HNSCC patients compared to healthy controls (Cai et al. 2017), while another meta-analysis confirmed DAPK promoter hypermethylation among OSCC patients (Don et al. 2014) as well as an association with a higher risk of nasopharyngeal carcinoma (Zhang et al. 2018a).