Enzymes relevant for the initiation of GAG formation and heparan sulfate chain elongation, beta-1,3-glucuronyltransferase 3 (B3GAT3), multiple exostosin-like 2 (EXTL2) and EXT2 heparan sulfate copolymerase (EXT2), display enhanced expression in myeloma cells. Here, EXTL2 is linked to plasma cell myeloma.