FOXP3 and neoplasm: In contrast, regulatory/suppressor T cells (Treg), characterized ex vivo by high expression of the IL-2R α-chain (CD25) and of the lineage-specific transcription factor FOXP3 and low expression of the IL-7R α-chain (CD127), are believed to inhibit anti-tumor responses [3], [4], [5], [6], [7].