Preventing tumor-cell induced bone disease

Bone is a highly hospitable environment for colonization and growth of metastatic tumors, and some of the most common human malignancies, notably breast cancer and prostate cancer, have a strong propensity to produce skeletal metastases. In most cases, tumor cells cause bone disease by co-opting the physiologic mechanisms that normally enhance the production of osteoclasts. In particular, they produce a cytokine called RANK, which activates a vicious cycle of osteolysis and increased osteoclast activation. In this issue of the Journal, Zhang et al show that an endogenous inhibitor of RANK signaling blocks osteoclastic osteolysis and promotes the destruction of human prostate cancer cells that had been introduced into mice.