Although EBV-induced LMP1 and the IFN-γ pathway jointly regulate PD-L1 expression in NPC cells, with PD-L1 expression being higher in EBV-positive NPC cells than in EBV-negative NPC cells (26), no correlation was found between PD-L1 expression levels and plasma EBV DNA copy numbers (27). This evidence concerns the gene CD274 and nasopharyngeal carcinoma.