ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: CircCRKL was substantially expressed in CML patients relative to normal donors, as demonstrated in Fig. 1A. Furthermore, when comparing BCR-ABL+ cell lines (K562, K562/G01, KCL22, and SupB15) to BCR-ABL− cell lines (TK6 and THP-1), it was surprising to find that the circCRKL expression was significantly higher in BCR-ABL+cell lines (Fig. 1B).