Our data showed that VP significantly downregulated the expression of PD-L1 in HNSCC cells, consistent with the results of Hsu et al. who reported that PD-L1 expression was correlated with YAP expression and VP downregulated PD-L1 expression in human malignant pleural mesothelioma 51. This evidence concerns the gene CD274 and head and neck squamous cell carcinoma.