When injected under limiting dilution conditions, the leukemia initiating potential of T-ALL cells expressing only Nfat4 (Fig 3B, left, “input” panel) was comparable to that of cells expressing both Nfat2 and Nfat4 (Fig 3C, left panel, compare red and blue tracings; Table 2). This evidence concerns the gene NFATC3 and acute lymphoblastic leukemia.