CXCL12 and neoplasm: We thank members of the FACS facility (Laurie Gilmour, Wendy Tombo, Rupak Neupane, and Jim Cupp) for their technical support, Terence Wong and Anan Chuntharapai for purification of the SDF1 antibody, Jeffrey Eastham-Anderson for microscopy assistance, Hartmut Koeppen for scoring tumor micro-vessels, and Pamela Cowin for providing ΔNβcat tumors.