Retroviral expression of the full length 752 amino acid protein in murine hematopoietic stem cells (HSCs) failed to produce leukemia or signs of altered hematopoiesis when transplanted into lethally irradiated recipient mice, however, and led to the conclusion that RUNX1-RUNX1T1 alone is insufficient for leukemogenesis (59). Here, RUNX1 is linked to leukemia.