BCL6 and head and neck squamous cell carcinoma: The differentiation and function of Treg cells depend on its lineage-specifying transcription factor Foxp3, which is critical for Treg cell-mediated immune homeostasis.26, 27, 28 In the 4NQO-induced HNSCC model, despite the comparable proportion of Treg cells, the deletion of Bcl6 lead to extensively repressed Foxp3 expression in Treg cells from the tongue and dLNs, indicating the pivotal role of Bcl6 in maintaining the lineage stability of Treg cells.