Myeloid differentiation factor 88 (MYD88, 60%-80%) and CD79B (50%-60%) are more frequently mutated in PCNSL, and present not only in inactivated B cell-like-DLBCL (ABC-DLBCL) but also in germinal B cell-like-DLBCL (GCB-DLBCL) (9–11). The gene discussed is CD79B; the disease is diffuse large B-cell lymphoma.