ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: Genomic DNA-based PCR, in TKI discontinuation clinical trials, revealed that patients continued to harbor the BCR-ABL1 gene after discontinuation of imatinib, even in patients with TFR [62,63], suggesting that the patients’ immune systems suppressed the residual CML-LSC and prevented disease recurrence.