DKK1 and head and neck squamous cell carcinoma: By analyzing the expression profiles of HNSCC patients downloaded from the TCGA database, Liu et al. identified six differentially expressed genes (DEGs) associated with OS in HNSCC patients (DKK1, HBEGF, RNASE7, TNFRSF12A, INHBA, and IPIK3R3), and developed a reliable DEG-based risk model [19].