Twelve out of the 15 DLBCL cases with duplications in 11q25 shared a common duplication of approximately 340 Kb located 86 kb upstream of B3GAT1, a member of the glucoronyltransferase gene family whose gene product functions in the biosynthesis of the carbohydrate epitope HNK-1 (human natural killer-1, also known as DC57 and LEU7). Here, B3GAT1 is linked to diffuse large B-cell lymphoma.