As the PK–PD relationship for a targeted agent such as imatinib may be confounded by genotypic heterogeneity of intracellular pharmacological targets (BCR-ABL and c-KIT, respectively), the mutational status of BCR-ABL was also assessed in our CML population by DNA sequencing. Here, ABL1 is linked to chronic myelogenous leukemia, BCR-ABL1 positive.