Although not included in this study, our NGS results for CNS DLBCL had a higher 9p21 (including CDKN2A and CDKN2B) loss ratio (13/17, 76.5%) than DLBCL NOS (43/154, 27.9%). The gene discussed is CDKN2B; the disease is diffuse large B-cell lymphoma of the central nervous system.