CD274 and esophageal squamous cell carcinoma: Analyzing data from the Cancer Genome Atlas (TCGA) database, patients with positive PD-L1 expression and EMT have a worse prognosis compared to those with positive PD-L1 and negative EMT in head and neck squamous cell carcinoma [17]; moreover, a negative prognostic potential as well as high risk of recurrence and tumor progression have been reported in esophageal squamous cell carcinoma (ESCC) [11].