The foremost hallmark of chronic myelogenous leukemia (CML), the Philadelphia (Ph) chromosome, arises from a t (9;22) translocation fusing the Abelson murine leukemia (ABL1) locus on chromosome 9 with the breakpoint cluster region (BCR) gene on chromosome 22 [1]. This evidence concerns the gene ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive.