KARYOTYPE: HEMATOLOGIC: BONE MARROW: Acute Promyelocytic Leukemia, AML, M3 (FAB); t(15;17) is consistently associated with APL resulting in a fusion gene for PML and RAR-alpha which accounts for response to retinoid therapy. RAR is retinoic acid receptor. Besa/Peter C. Nowell, M.D. Karyotype Slides