To determine the role of Necdin in MLL-AF9-induced leukemia, we transplanted 100,000 wild type or Necdin null HSPCs expressing MLL-AF9 cells (CD45.2+ GFP+) into lethally irradiated recipient mice (B6.SJL mice, CD45.1+) together with 100,000 normal competitor cells (CD45.1+). Here, KMT2A is linked to leukemia.