RIPK4 and head and neck squamous cell carcinoma: This reduction leads to reduced immune-killing cell infiltration and facilitates HNSCC progression and immune evasion.599 Yan et al. displayed that Irf6 loss triggered rapid HNSCC development in mouse models, while Notch/Ripk4/Irf6 axis activation suppressed tumor growth in vitro.600 These findings illustrate that IRF1, IRF2, IRF3, and IRF6 play an inhibitory effect on HNSCC.