Luciferase reporter assays were then performed on UM1 and UMSCC5 cells transfected with an empty promoter reporter plasmid, the Sox11 gene promoter reporter plasmid, the Sox11 gene promoter reporter with the Stat3 plasmid (STAT3), or the Sox11 gene promoter reporter and the mutated Stat3 plasmid (STAT3∆DBD) to further confirm that STAT3 regulates the expression of Sox11 in HNSCC cells. Here, STAT3 is linked to head and neck squamous cell carcinoma.