Furthermore, our previous studies showed that patients selected in this way are representative of AML in general with regard to cytogenetic analysis and FLT3 abnormalities, the most important genetic markers for prognostication and in vivo chemosensitivity.18 Leukemic blood cells are sufficiently representative of corresponding bone marrow AML cells; although there are quantitative differences, the major characteristics are comparable.4 Finally, our methods for cryopreservation and thawing are highly standardized. Here, FLT3 is linked to acute myeloid leukemia.