Importantly, while SLC6A6 knockdown reduced the engraftment of primary AML cells by 1.2- to 40-fold in patient-derived xenograft models (Fig. 4k,l), it did not significantly impair engraftment of normal human CD34+ HSPCs in xenograft models (Fig. 4m). This evidence concerns the gene SLC6A6 and acute myeloid leukemia.