Likewise, in primary human AML, Xu and colleagues showed that engraftment of AML stem cells in NOD/SCID mice were dramatically reduced in the presence of both rapamycin and etoposide compared to etoposide treatment alone, hence confirming that mTOR regulate AML stem cell survival following rapamycin treatment (Xu et al., 2005). This evidence concerns the gene MTOR and acute myeloid leukemia.