A more recent Japanese retrospective analysis in pediatric AML with RUNX1‐RUNX1 T1 identified CD19 negativity as the sole significant risk factor for relapse, a result still true even when restricting patients without the KIT exon 17 mutation, implying a biological difference between CD19‐positive and CD19‐negative AML patients with RUNX1‐RUNX1 T1.20 Here, CD19 is linked to acute myeloid leukemia.