In myeloid leukemia, cells with tumorigenic potential express CD34 and are negative for CD38 (CD34+/CD38−), as well as normal blood cells characterized by the ability to repopulate the hematopoietic system of SCID (severe combined immunodeficient) mice, suggesting that tumor cells could derive from these precursors [3]. This evidence concerns the gene CD38 and myeloid leukemia.