BCR and chronic myelogenous leukemia, BCR-ABL1 positive: In K562 cells, a CML-derived cell line known to harbor BCR-ABL, Bru-seq revealed high BCR expression throughout most of the 5′-part of the gene with a drastic drop in RNA reads at the known translocation site near the 3′-end of the gene (Supplementary Fig. 4a, left panel, red arrow).