IRF9 and head and neck squamous cell carcinoma: The distribution of each IRF family gene's genomic alterations in the TCGA HNSCC dataset is shown as follows: IRF1 (1.4%), IRF2 (4%), IRF3 (0.5%), IRF4 (1.7%), IRF5 (1.4%), IRF6 (1.9%), IRF7 (1.3%), IRF8 (1.1%), and IRF9 (1.5%).