Using the same criteria as in the discovery cohort, the B-other cases in the validation cohort could be subdivided into DUX4-rearranged BCP ALL (n=20), ‘B-other, with fusion' (n=14), ‘B-other, without fusion' (n=7), Ph-like (n=4; Supplementary Fig. 9b) or ETV6-RUNX1-like (n=4; Supplementary Fig. 10). This evidence concerns the gene DUX4 and acute lymphoblastic leukemia.