DKK1 and plasma cell myeloma: Studies by the Roodman laboratory and others have demonstrated that multiple-myeloma-derived factors including interleukin-3 (IL-3) [96,97], sclerostin [98], TGF-beta [99,100], interleukin-7 (IL-7) [101], tumor necrosis factor-alpha (TNF-alpha) [101], DKK1 [102], and the zinc finger protein GFI1 [101] all contribute to suppression of osteoblast differentiation and bone deposition.