Acute promyelocytic leukemia is associated with t (15:17) w result in formation of PML-RARA chimeric protein w induces an arrest of differentiation of the gronulocytic lineage at the level of promylocytic cells and expansion of the leukemic promeylocytes so genetic diagnosis of this disease is important in the treatment as the ATRA drugs is able to induce remission of the disease and AS203 drug w causes apoptosis of leukemic cells. The best method for diagnosis is RT-PCR.