CD274 and Epstein-Barr virus infection: Alterations of 9p24.1/CD274(PD-L1)/PDCD1LG2(PD-L2), which constitute a defining feature of cHL and increase PD-L1 or PD-L2 expression, have been shown to be similarly distributed in patients with EBV-negative and EBV-positive cHL, but EBV-positive cHLs displayed higher PD-L1 H-scores (percentage of RS cells with positive staining multiplied by the average intensity of positive staining), suggesting further induction of PD-L1 expression by EBV infection [64].