KRAS and precursor B-cell acute lymphoblastic leukemia: Passet et al. [5] described a cohort of 30 PAX5-P80R-mutated adult B-ALL patients which all showed inactivation of the second PAX5 allele (mutation or loss) and the majority harbored CDKN2A loss (74%) and an NRAS and/or KRAS mutation (73%).