RUNX1 and acute lymphoblastic leukemia: The discovery set consisted predominantly of BCP-ALL cases with either an ETV6-RUNX1 rearrangement (t(12;21)) or double trisomy of chromosomes 4 and 10/high hyperdiploid (>50 chromosomes) tumour karyotype (DT/HHD)9, 12, 13, 14.