CD274 and B-cell non-Hodgkin lymphoma: In 20% of DLBCLs cases, PD-L1 overexpression on tumor cells' surfaces refers to genetic alterations.37Another factor that may cause PDL-1 overexpression on tumor cells is Epstein–Barr virus initiation (EBV) activation, which may drive immune tolerance.38Many studies correlate increased EBV infection with the development of aggressive B cell lymphoma.39The most acceptable scenario is the correlation of increased IFN-γ in inflammatory process that accompanied the tumor progression as explained above.