ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: CML was formerly associated with poor prognoses, but the prognoses of CML patients has improved considerably over the past 20 years because of the introduction of tyrosine kinase inhibitors (TKI) specific for ABL1, such as imatinib, which inhibits BCR::ABL1 kinase activity [3].