In the 4-nitroquinoline 1-oxide (4-NQO) carcinogen model of HNSCC, transiently knocking out FOXP3 cells in mice that express FOXP3 under a human diphtheria receptor caused increased T cell infiltrate in the tumor but 2.5 times increase in progression to HNSCC [33]. Here, FOXP3 is linked to head and neck squamous cell carcinoma.