Age-specific cell characteristics have been shown to play a detrimental role in leukemias driven by the NUP98-HOXA9 (Chaudhury et al., 2018), ETV6-RUNX1 (Böiers et al., 2018), and ETO2-GLIS2 (Lopez et al., 2019) oncogenes. Here, RUNX1 is linked to leukemia.