Signaling molecules and pathways involved in MSC tumor tropism.

Human bone marrow is a reservoir containing cells with different self-renewal capabilities, such as mesenchymal stem cells (MSC) and hematopoeitic stem cells (HSC). MSC in particular have been increasingly used in preclinical and clinical treatment of tissue regenerative disorder. Understanding the molecular mechanisms underlying MSC homing and mobilization is critical to the design of rational cell therapy approaches. In this review, we will discuss the key molecular mechanisms that govern the homing of MSC to bone marrow, the mobilization of MSC to tumors and injured sites via circulation, and strategies that enhance MSC migration.