[Bone marrow-derived cells contribute to niche formation in cancer progression]

Bone marrow-derived cells, which are recruited to peripheral tissues, have been shown to play a major role as angiogenic factor supplier. Moreover, bone marrow-derived "hemangiocytes" through graded chemokines production, can function as the molecular hub for hematopoietic cytokine-induced neovascularization. Current focus on cancer metastasis has centered on the intrinsic factors regulating the cell autonomous homing of the tumor cells to the metastatic site : Bone marrow-derived cells expressing vascular endothelial growth factor receptor 1 can be mobilized into the circulation due to growth factors released by the primary tumor. These cells cluster at distant sites, "the premetastatic niche" , where they set up a microenvironment ideal for tumor cells to seed, thereby completing the metastatic spread. Focus on the early cellular and molecular events in cancer infiltration, metastasis and proliferation will likely lead to new approaches to detect and prevent metastasis at its earliest inception.