PDCD1LG2 and classic Hodgkin lymphoma: Moreover, in cHL, the amplification of 9p23-24 gene is responsible for PD-L1/PDL-2 encoding in RS cells, as well as for the activation of Janus kinase 2 (JAK-2) gene, what additionally increases production of PD-L1 through JAK/signal transducer activator of transcription (STAT) signal transduction pathways [33].