To investigate the full spectrum of circRNAs expressed during malignant B-cell development, we examined high-depth ribo-depleted RNA-seq data of 105 B-ALL patients representing six genetic B-ALL subtypes: ETV6::RUNX1/like, Hyperdiploid, DUX4-rearranged, MLL-rearranged, Ph+/like, and TCF3::PBX1 (Table 1). Here, KMT2A is linked to precursor B-cell acute lymphoblastic leukemia.