ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: However, fluorescence in situ hybridization (FISH) revealed BCR‐ABL1 rearrangement (95% of cells) in both cells with round nuclei (blasts) and cells with segmented nuclei (neutrophils) (Figure 1F), supporting the diagnosis of chronic myeloid leukemia, blast phase (CML‐BP) rather than de novo Ph+ T‐ALL.