Miller et al. was the first to conduct NK cell transfer in adult AML patients without prior HCT, reporting that haploidentical NK cell transfer with the intense high-dose cyclophosphamide and fludarabine immune suppression regimen, CD3 depletion and IL-2 administration both ex vivo and in vivo was a safe treatment with successful NK cell proliferation and activation in R/R AML (CR 5/19) [88]. This evidence concerns the gene IL2 and acute myeloid leukemia.