The FISH analysis revealed that all CML cell lines have a balanced t(9;22) translocation, based on a fusion of the 3′ ABL1 region at 9q34 with the 5′ BCR region at 22q11, while HL-60 was Philadelphia chromosome-negative, as expected (Figure 1a). This evidence concerns the gene ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive.