Tumor-infiltrating total CD3+ gated Foxp3eGFP+ Treg cells are not altered, whereas activated KLRG1+ Treg cells are significantly decreased in the ST2−/−Foxp3eGFP+ Treg cell group versus the WT Foxp3eGFP+ Treg cell group (Supplementary Fig. 10A, B), which paralleled decreases in CD3− gated MLL-AF9eGFP+ leukemic cells at serial timepoints of Day 5, 10 and >20 in leukemic models with doses of 105 and 106 MLL-AF9eGFP cells (Fig. 4C; Supplementary Fig. 11). Here, KLRG1 is linked to neoplasm.