“Stem/B” cells are more quiescent and less actively cycling than leukemic “Pro-B” cells, highlighting the importance and feasibility of tracking rare but distinct leukemia cell populations in patients undergoing therapy.[19] Obro et al[3] reported that the subpopulations are most commonly characterized by a bimodal expression of CD34 in childhood B-ALL patients. This evidence concerns the gene CD34 and leukemia.