CD26+ stem cells reconstitute BCR-ABL1+ leukemia, whereas CD26− stem cells reconstitute normal hematopoiesis; targeting of CD26 by gliptins suppresses expansion of CML cells and improves engraftment of normal HSCs during aHSCT. The gene discussed is DPP4; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.