PDCD1 and Hodgkins lymphoma: In Hodgkin's lymphoma, frequent amplification of chromosome 9p24.1 that encodes PD-1 ligands PD-L1 and PD-L2 was observed, and the active JAK/STAT signaling further induced PD-L1/2 expression, which could be associated with the higher clinical response in Hodgkin lymphoma in response to PD-1/PD-L1 blockade [63].