HOXA6 and leukemia: As expected, AE9a‐Ddit4−/−Hoxa6 cell‐transplanted mice developed leukemia with a significantly shorter survival time (median survival: 53 days) compared with AE9a‐Ddit4−/−Vec mice (Fig. 7D), indicating that re‐expression of Hoxa6 in AE9a‐Ddit4−/− cells accelerated leukemia development.