CD274 and Epstein-Barr virus infection: In previous studies, expression of PD-1/PD-L1 could be upregulated by EBV infection in various malignancies [34–37], and blockade of PD-1/PD-L1 interactions successfully inhibited EBV-induced lymphoma growth in a mouse model [38], suggesting a possible interaction between EBV and PD-1/PD-L1 pathway in tumor immunology.