DKK1 and plasma cell myeloma: Heparanase enhances osteoclastogenesis and bone loss – a major cause of morbidity in patient with multiple myeloma – by shifting the differentiation potential of osteoblast progenitors from osteoclastogenesis to adipogenesis possibly via induction of the Wnt signaling pathway inhibitor DKK1 by both osteoblast progenitors and myeloma cells (128).