CD274 and extranodal nasal NK/T cell lymphoma: Regarding the underlying molecular mechanisms, higher PD-L1 and/or PD-L2 expression levels were associated with a gain of chromosome 9p24 on neoplastic cHL cells [263,264], since PD-L1 is induced by the EBV-encoded LMP1 through the NF-ĸB pathway in NK/T cell lymphoma [265] and in DLBCLs by the EBNA2 gene product.