PDCD1LG2 and primary central nervous system lymphoma: Genetic alterations of chromosome 9p24.1 of PD-L1 and/or PD-L2 have also been reported in PMBL, and in two other lymphoma subtypes that arise in immune-privileged extranodal sites, i.e., PCNSL, and primary testicular lymphoma (PTL) [58,71,80,81,82,83].