After the injection of 1 × 105 K562-GFP cells, successful reconstitution of leukemia was observed in NSI (medium survival time 27 days) and NOD-scid (medium survival time 48 days) mice (Fig. 1b), but not in IL2Rg−/−, scid, Rag2−/−, nude, or WT mice. The gene discussed is IL2RG; the disease is leukemia.