CDH1 and head and neck squamous cell carcinoma: We previously reported that EMT is associated with PD-L1 upregulation in gefitinib-resistance in NSCLC [13] and that EMT is associated with PD-L1 expression in HNSCC [15]; thus, we evaluated the expression of EMT markers such as E-cadherin and vimentin in cisplatin-treated HNSCC cells.