(A): Representative images of iPSC colonies generated from AML patient Fibs. capable of normal in vitro differentiation to myeloid lineages and are devoid of leukemia-associated aberration found in matched patient bone marrow. Skin fibroblasts were obtained from AML patients whose leukemic cells possessed a distinct, leukemia-associated aberration, and used to create AML patient-specific induced pluripotent stem cells (iPSCs). Through hematopoietic differentiation of AML patient iPSCs, coupled with cytogenetic interrogation, we reveal that AML patient-specific HPCs possess normal progenitor capacity and are devoid of leukemia-associated mutations. Importantly, in rare patient skin samples that give rise to mosaic fibroblast Ibuprofen (Advil) cultures that continue to carry leukemia-associated mutations; healthy Ibuprofen (Advil) hematopoietic progenitors can also be generated via reprogramming selection. Our findings provide the proof of principle that cellular reprogramming can be applied on a personalized basis to generate healthy HPCs from AML patients, and should further motivate advances toward creating transplantable hematopoietic stem cells for autologous AML therapy. Stem Cells 2013;33:1839C1849 Keywords: Acute myeloid leukemia, Chromosome aberrations, Human induced pluripotent stem cells, Hematopoietic progenitor cells, Reprogramming Introduction Acute myeloid leukemia (AML) is characterized by the rapid growth of nonfunctional immature myeloid cells (AML blasts) in the bone marrow (BM) and peripheral blood (PB) of patients, leading to anemia, bleeding, increased risk of infection, and ultimately death 1,2. Accumulated clinical data have identified recurrent leukemia-associated genomic aberrations in 50%C60% of AML patients 3C5, and these mutations are used as informative diagnostic and prognostic markers that are useful in managing patient therapy. Current treatments achieve high rates of remission, but subsequent relapse contributes Ibuprofen (Advil) to a reduction to 20%C30% of patients who attain disease-free survival 6,7. Although hematopoietic progenitor Ibuprofen (Advil) cell (HPC) transplantation during consolidation therapy significantly reduces relapse 8, safe autologous sources of HPCs required for normal hematopoietic recovery are limited, and include concerns of reinfusion of leukemic cells with genomic abnormalities. Unfortunately, current graft purging methods 9 do not alleviate the risk of leukemic cell reinfusion and relapse in autologous BM transplantation settings 10C12. Alternatively, use of allogeneic blood sources to avoid leukemic abnormalities (BM, mobilized PB, and cord blood) 13 for transplantation in AML patients is restricted by the availability of matched donors, and the long-term complications associated with an inability to separate graft-versus-host disease EPOR from the beneficial graft-versus-leukemia effect 6,14,15. Furthermore, alternative efforts over the past decades to increase the low numbers of HPCs that can be obtained for the management of a single patient 16 by ex vivo expansion have had variable success 13,17, where recent clinical trials question the benefits of expanded HPCs 17. As such, the generation of novel autologous sources of HPCs to circumvent limited availability and complications associated with current transplant sources could benefit patient survival, and thus deserves deeper investigation. The ability to generate induced pluripotent stem cell (iPSCs) that share phenotypic, molecular, Ibuprofen (Advil) and functional hallmarks with human embryonic stem cells 18C22 provides an opportunity to develop renewable sources of immune-compatible cells. In the context of AML, generation of AML patient-specific HPCs that are devoid of the leukemic aberration(s) that affect the patients hematopoietic tissue would provide a transformative approach in establishing a healthy autologous blood source for transplantation during AML therapy. Although robust long-term engraftment of PSC-derived HPCs in murine xenografts has not been fully demonstrated 23,24, incremental advances have been made 25C27. However, multiple studies have delineated protocols to differentiate human PSCs to HPCs that possess in vitro multipotent functionality 28C31. Independent of advancements required for the generation of transplantable long-term HPCs from hPSCs, the potential of using reprogramming to generate healthy blood cells from an AML patient has yet to be explored and it remains unclear whether generation of AML patient HPCs is even possible. To this end, we obtained dermal fibroblasts from human AML patients whose leukemic cells possessed known leukemia-associated genomic aberration, and used reprogramming technology to generate HPCs. By probing for the absence of this aberration, in conjunction with immunophenotypical, functional, and morphological in vitro assessments as compared to the patients AML blasts, we provide evidence that.