CD38 and leukemia: Leukemia stem cells (LSCs) may cause relapse from the complete remission (CR) state.10 CD34+CD38‐ is a putative immunophenotype of LSCs with the ability to generate leukemia in immunodeficient mice.11, 12, 13 However, this immunophenotype has been challenged because some studies have demonstrated that LSCs might exist in CD34+CD38+ and CD34‐ cells.14, 15, 16 Thus, this surface immunophenotype alone might be inadequate for identifying LSCs.