LSCs are well accepted to be a CD34-positive and CD38-negative cell population with the ability to reconstitute human AML in immunodeficient mice regardless of the morphological subtype of AML,6 although recent studies have suggested that LSCs could also exist in CD34+/CD38+ or CD34− blast populations at least in some types of AML.7 KG1α and Kasumi-1 cell lines derived from male AML patients, both of which have high percentage of CD34+CD38− population, are widely used for in vitro and in vivo studies of LSCs.8 Here, CD38 is linked to acute myeloid leukemia.