DAPK1 and head and neck squamous cell carcinoma: In the control source, the significant association between DAPK promoter methylation and HNSCC was seen among the autologous group and the heterogeneous group in the random-effect model (autologous group, OR = 2.71, 95% CI = 1.49–4.93; heterogeneous group, OR = 9.50, 95% CI = 2.98–30.27).