Cluster 5/MCD DLBCL is dominated by ABC-DLBCL cases and is enriched for co-occurring mutations leading to activation of BCR signaling (CD79B) and the Toll-like receptor (TLR) pathway (MYD88, particularly through the highly recurrent p.L265P hotspot mutation) (2, 3, 28, 48, 65, 68, 126, 127). Here, BCR is linked to diffuse large B-cell lymphoma.