Chemokines and primary brain tumors

Normal development of the central nervous system (CNS) is critically dependent upon the coordinated expression of chemokines and their receptors in a spatially and temporally regulated fashion (reviewed in Klein and Rubin 2004; Li and Ransohoff 2008). During development, chemokines control progenitor cell migration (Bagri et al. 2002; Klein et al. 2001; Lu et al. 2002; Lu et al. 2001), proliferation (Klein et al. 2001), and survival (Chalasani et al. 2003a) as well as modulate differentiated cell functions such as axon pathfinding and fasciculation (Chalasani et al. 2003b; Chalasani et al. 2007). Thus, it should not be surprising to discover that chemokines and their receptors also contribute to the biology of CNS neoplasms. In this chapter we will primarily review studies that have defined the role that one chemokine, CXCL12, and its receptor, CXCR4, play in brain tumor biology and how this pathway is being targeted for brain tumor therapy. In addition, we will touch on the role that brain tumor-derived chemokines play in the recruitment of inflammatory cells to sites of brain tumor growth.