In leukemia the single cell functional plasticity of the RUNX1-miR-221-KIT axis that regulates normal proliferation and differentiation can be undermined not only by the RM8 fusion protein, but also by genetic mutations, including other non-random cytogenetic rearrangements affecting RUNX1 or CBFB [21–23]. The gene discussed is RUNX1; the disease is leukemia.