The 2B4/CD3ζ/soluble interleukin-15 (sIL-15) CAR-NK cells show comparable tumor control against CD123+ MV-4-11 cells in vivo to 2B4/CD3ζ CAR-NK while displaying an exponential increase in the circulating cell count (35 days; n=5-7). This evidence concerns the gene IL15 and neoplasm.