ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: BCR‐ABL tyrosine kinase point mutations and LSC outgrowth are the two main events resulting in imatinib resistance and CML propagation.14, 20, 21 For the BCR‐ABL tyrosine kinase mutation analysis, we performed nest PCR to amplify the ABL kinase domain of BCR‐ABL gene using genomic DNA extracted from TF1‐BAR and KCL‐22‐R cells.