CXCL12 and neoplasm: We also tested the possibility that allo-TCXCR4 could outcompete Tregs for limiting CXCL12-dependent niches within the tumor (45), by adapting the experimental design and cotransferring donor-strain luc+ Tregs at a 1:1 ratio with either TCXCR4 or TControl (both from B6 non-luc+ donors).