FOXP3 and neoplasm: The preferential tumor recruitment of Tregs was intrinsic to Tregs since parabiosis experiments between WT and Foxp3-EGFP CCR2-/- mice show that EGFP+ CCR2-/- Tregs which migrated to the tumor tissue represented only 20% of total Treg in both WT hosts and CCR2-/- hosts.