BCR and cancer: To establish a cancer-relevant model system of augmented RNA editing, the BCR-ABL1-expressing human leukemia cell line K562 was stably transduced with lentiviral human ADAR1-GFP (K562-ADAR1); lentiviral ADAR1 mutant (A5293C) that lacks deaminase activity [26] (catalytically inactive, K562-ADAR1m); or vector open reading frame control (K562-ORF, Figure 1E).