To dynamically monitor ST2+ Treg cells in malignant BM niches, we developed two aggressive leukemic models: MLL-AF9eGFP and DNMT3A/FLT3ITD, and confirmed in both the increases of KLRG1+ST2+ Treg cells in the BM TME with the progression of leukemia. This evidence concerns the gene KLRG1 and leukemia.