BCR and chronic myelogenous leukemia, BCR-ABL1 positive: Over the past two decades, the introduction of the first- (1G), second- (2G) and third- (3G) semi-specific BCR::ABL1 tyrosine kinase inhibitor (TKI) has significantly improved the outcome of patients with CP CML, achieving unprecedented rates of hematologic, cytogenetic and molecular response [18,19,20].