RUNX1 and Splenomegaly: At 9 months post-transplantation, four of six mice transplanted with BM cells expressing both ASXL1-R693X and RUNX1-R135T mutants died with marked splenomegaly and hepatomegaly, and a short median survival of 24 weeks compared with one of the five mice transplanted with BM cells expressing either ASXL1 or RUNX1 mutant died with a medium latency of 37.2 weeks (Fig. 4a–d).