DKK1 and plasma cell myeloma: The osteoinductive properties of GSK3β inhibitors have been demonstrated both in vivo and in vitro by numerous investigators (Gregory et al, 2006), proteasomal inhibitors have been shown to reduce Dkk-1 and RANKL levels (Terpos et al, 2006), and the benefits of administration of an anti-Dkk-1 antibody have recently been demonstrated in a murine model of multiple myeloma (Yaccoby et al, 2007).