CD274 and classic Hodgkin lymphoma: Based on these findings, Uccini et al. used immunostaining to measure the expression of PD-1 and PD-L1 in 53 cases of cHL in children under 14 years of age and, apart from confirming that PD-L1 levels are higher in EBV cases, proved that increased PD-L1 expression is independent of 9p24.1 amplification, as all of the EBV positive cases were negative for 9p24.1 amplification by fluorescent in situ hybridization [74].