Gene-edited MLLr hUCB cells develop leukemia in xenotransplanted mice. (A) Survival curves for xenotransplanted mice with mean latencies for development of primary (1st.), secondary (2nd.), and tertiary leukemias (3rd.) of 251, 48, and 96.5 days, respectively. Latencies and P values were determined using the log-rank test. Leukemic involvement of spleen (B), leg bones (C), peripheral blood (PB) (D; upper panels), and BM (D; lower panels, Giemsa stain). Scale bars, 100 μm. (E) Hematoxylin and eosin–stained sections of the indicated tissues from control and leukemic mice.