Reportedly, approximately 90% of PCNSL cases are DLBCLs,5 and recent studies have shown an accumulation of mutations in genes such as MYD88, CD79B, TBL1XR1, PIM1, IGLL5, and BTG1 in PCNSL cases.6, 7, 8, 9, 10, 11. The gene discussed is PIM1; the disease is primary central nervous system lymphoma.