CD274 and head and neck squamous cell carcinoma: Muller L. et al. showed that the signals produced by exosomes isolated from HNSCC (head and neck squamous cell carcinoma) modulate gene expression in human Tregs, and the highest transcriptional activity was observed in immunoregulatory genes such as PD-L1, PD-1, CD40L, CD25, and ZAP-70 [113].