Test Details: Chromosomal translocation t(9,22) associated with BCR and ABL genes resulting in BCR-ABL fusion transcripts and consequent BCR-ABL tyrosine kinase protein. The presence of BCR-ABL fusion transcripts confirms diagnosis of chronic myeloid leukemia (CML) and Ph positive acute lymphoblastic leukemia (ALL). Mutations in the BCR-ABL kinase domain may cause, or contribute to, resistance to tyrosine kinase inhibitors (TKIs) in chronic myeloid leukemia patients. The test is indicated for monitoring targeted drug therapy response in CML patients. The test is also recommended in pH+ CML patients on failure to achieve either complete hematologic response at 3 months ; complete cytogenetic response at 6-12 months, loss of hematologic and cytogenetic response at any point during drug therapy, significant increase in BCR-ABL transcript levels post treatment.