A new window on MSCs.

croenvironment, Wnt3A acts to promote osteoblast differentiation and suppress osteoclastogenesis. This results in inhibition of myeloma bone disease and consequent indirect suppression of tumor growth. These studies advance our knowledge of myeloma bone disease, and raise questions regarding the balance of agonists and antagonists of the Wnt signaling pathway in myeloma, and the function of Wnt signaling in myeloma cells. The conclusions by Qiang and colleagues provide strong support for the potential of targeting the Wnt signaling pathway within the bone marrow microenvironment for the treatment of myeloma bone disease. Furthermore, they highlight the complex interdependence between myeloma cells and host cells of the bone marrow niche, along with the importance of studying myeloma within the appropriate microenvironment. Conflict-of-interest disclosure: The author declares no competing financial interests. ■