Wnts, bone and cancer.

The Wnt pathway plays vital roles in bone and in cancer. In this issue of The Journal of Pathology, Cai and colleagues report results that suggest that the Wnt pathway is inactivated in bone cancers, a finding that could have significant implications for the development of Wnt agonists as bone anabolic agents. While these findings are at odds with the prevailing view that the Wnt pathway is oncogenic in all systems studied to date, they remind us how complex and still poorly understood this important signalling pathway remains. At the very least, these findings should provoke debate and stimulate further research into the role of Wnt signalling in osteosarcoma.