RUNX1 and acute myeloid leukemia: AML with mono- and biallelic RUNX1 mutations has been provisionally classified by the WHO as “AML with mutated RUNX1” (distinct from CBF-AML) to reflect the possible worse prognosis as compared to other AML types (Tang et al., 2009; Gaidzik et al., 2011, 2016; Schnittger et al., 2011; Mendler et al., 2012; Arber et al., 2016).