Bone, as well as lung and liver, is one of the most preferential metastatic target sites for cancers including breast, prostate, and lung cancers. Although the precise molecular mechanisms underlying this preference need to be elucidated, it appears that bone microenvironments possess unique biological features that enable circulating cancer cells to home, survive and proliferate, and destroy bone. In conjunction, cancers that develop bone metastases likely have the capacity to utilize these unique bone environments for colonization and bone destruction. This crosstalk between metastatic cancer cells and bone is critical to the development and progression of bone metastases. Disruption of this interaction will allow us to design mechanism-based effective and specific therapeutic interventions for bone metastases. (C) 2004 Elsevier Inc. All rights reserved.