While 24 hour AraC treatment did not affect the viability of leukemia cells expressing MLL-AF9 (Figure 3A), we found that Necdin null leukemia cells expressing MLL-AF9 were sensitive to extended AraC treatment (48 hour) in a dosage-dependent manner, manifested by decreased viability (Figure 3B). This evidence concerns the gene KMT2A and leukemia.