LSCs appear to persist in most CML patients on TKIs, and the persistence of these cells remains a major obstacle to cure.[5, 7, 9] We previously reported that ALDH expression enriched for CD34+CD38− cells capable of engrafting NSG mice from normal marrow[18] as well as CML[20], thus, presumably representing the primitive stem cell fractions in both. This evidence concerns the gene CD38 and chronic myelogenous leukemia, BCR-ABL1 positive.