HOXA9 and acute myeloid leukemia: The p279 sample is a B-ALL that went on to lineage switch in response to ALL-directed chemotherapy and is the only sample that expresses both HOXA9 and IRX1. In p318, the AML that resulted from the lineage switch of p279, we found HOXA9 is downregulated, whereas the expression of IRX1 is maintained (Fig. 4j).