Contributions of the host microenvironment to cancer-induced bone disease.

The bone marrow provides a specialized and highly supportive microenvironment for tumor growth and development of the associated bone disease. It is a preferred site for breast and prostate cancer bone metastasis and the hematologic malignancy, multiple myeloma. For many years, researchers have focused upon the interactions between tumor cells and the cells directly responsible for bone remodeling, namely osteoclasts and osteoblasts. However, there is ever-increasing evidence for a multitude of ways in which the bone marrow microenvironment can promote disease pathogenesis, including via cancer-associated fibroblasts, the hematopoietic stem cell niche, myeloid-derived suppressor cells, and the sympathetic nervous system. This review discusses the recent advances in our understanding of the contribution of the host microenvironment to the development of cancer-induced bone disease.