That CHMP5 deficiency caused severe depletion of all CD34+ cells in primary murine T-ALL, including loss of the LIC-enriched CD34+MYC-GFPhi fraction, indicated that failure of CHMP5-deficient thymocyte progenitors to support ICN1-initiated T-ALL was likely due to impaired generation of LICs. Here, CD34 is linked to acute lymphoblastic leukemia.