CD274 and classic Hodgkin lymphoma: In classical Hodgkin Lymphoma (cHL) genomic amplification of the chromosomal locus 9p24.1, containing the genes encoding the inhibitory immune-checkpoint proteins programmed cell death ligand-1 (PD-L1) and PD-L2, which results in increased PD-L1 expression by Hodgkin Reed Stenberg (HRS) cells, have been reported.