In the early 1990s, with the introduction of new technologies such as fluorescence-activated cell sorting (FACS) and mouse xenografts assays for hematopoietic stem cells, Dick and colleagues found that tumor engraftment in acute myelogenous leukemia (AML) could only be initiated by CD34+/CD38- cell population (45). This evidence concerns the gene CD34 and acute myeloid leukemia.