While another cytotoxic agent cladribine, as a new generation of purine analog, has been considered to be a substitute for fludarabine in the combination with Ara-C plus G-CSF (CLAG) as a treatment in R/R AML patients [10], which is not only due to its same mechanism as fludarabine, but also attribute to its additional effects that cladribine induces cells apoptotic process through changing the membrane potential of mitochondria, repressing DNA methyltransferase (DNMT) as well as consuming methyl donors and, thus, we hypothesized that CLAG might be more effective than FLAG [2, 11–13]. Here, CSF3 is linked to acute myeloid leukemia.