To clarify the role of CXCR4 in homing of AML cells in a syngeneic AML model, Cas9+MLL-AF9 leukemia cells were transduced with the Cxcr4 or control sgRNA vectors, and 3 days later, cells were transplanted into sublethally irradiated mice. Here, MLLT3 is linked to acute myeloid leukemia.