TWIST1 and head and neck squamous cell carcinoma: Luciferase reporter assays were then carried out using an empty promoter reporter plasmid, Twist1 gene promoter reporter plasmid, Twist1 gene promoter reporter and Sox11 plasmid, and Twist1 gene promoter reporter and mutated Sox11 (Sox11FΔTAD) plasmid in UM1 and UMSCC5 to further confirm that SOX11 regulates the expression of Twist1 in HNSCC cells.