Definitive diagnosis requires testing for the PML/RARA fusion gene. This may be done by polymerase chain reaction (PCR), fluorescence in situ hybridization, or conventional cytogenetics of peripheral blood or bone marrow. This mutation involves a translocation of the long arm of chromosomes 15 and 17. On rare occasions, a cryptic translocation may occur which cannot be detected by cytogenetic testing; on these occasions PCR testing is essential to confirm the diagnosis. Treatment
Initial treatment
APL is unique among leukemias due to its sensitivity to all-trans retinoic acid (ATRA; tretinoin), the acid form of vitamin A. Treatment with ATRA dissociates the NCOR-HDACL complex from RAR and allows DNA transcription and differentiation of the immature leukemic promyelocytes into mature granulocytes by targeting the oncogenic transcription factor and its aberrant action. Unlike other chemotherapies, ATRA does not directly kill the malignant cells. ATRA induces the terminal differentiation of the leukemic promyelocytes, after which these differentiated malignant cells undergo spontaneous apoptosis on their own. ATRA alone is capable of inducing remission but it is short-lived in the absence of concurrent "traditional" chemotherapy. As of 2013 the standard of treatment for concurrent chemotherapy has become arsenic trioxide, which combined with ATRA is referred to ATRA-ATO; before 2013 the standard of treatment was anthracycline (e.g. daunorubicin, doxorubicin, idarubicin or mitoxantrone)-based chemotherapy. Both chemotherapies result in a clinical remission in approximately 90% of patients with arsenic trioxide having a more favorable side effect profile.ATRA therapy is associated with the unique side effect of differentiation syndrome.
Most deaths following remission are from other causes, such as second malignancies, which in one study occurred in 8% of patients. In this study, second malignancies accounted for 41% of deaths, and heart disease, 29%. Survival rates were 88% at 6.3 years and 82% at 7.9 years.In another study, 10-year survival rate was estimated to be approximately 77%. Epidemiology
Acute promyelocytic leukemia represents 10–12% of AML cases. The median age is approximately 30–40 years, which is considerably younger than the other subtypes of AML (70 years), however in elderly population APL has peculiar characteristics. Incidence is higher among individuals of Latin American or South European origin. It can also occur as a secondary malignancy in those that receive treatment with topoisomerase II inhibitors (such as the anthracyclines and etoposide) due to the carcinogenic effects of these agents, with patients with breast cancer representing the majority of such patients. Around 40% of patients with APL also have a chromosomal abnormality such as trisomy 8 or isochromosome 17 which do not appear to impact on long-term outcomes. References
External links

Sanz, Miguel A.; Grimwade, David; Tallman, Martin S.; Lowenberg, Bob; Fenaux, Pierre; Estey, Elihu H.; Naoe, Tomoki; Lengfelder, Eva; Büchner, Thomas; Döhner, Hartmut; Burnett, Alan K.; Lo-Coco, Francesco (2009). "Management of acute promyelocytic leukemia: Recommendations from an expert panel on behalf of the European Leukemia Net". Blood. 113 (9): 1875–1891. doi:10.1182/blood-2008-04-150250. hdl:1765/18239. PMID 18812465. PDQ Adult Treatment Editorial Board (2002–2020). "Adult Acute Myeloid Leukemia Treatment (PDQ®): Patient Version". Adult Acute Myeloid Leukemia Treatment (PDQ®). National Cancer Institute (US). PMID 26389377.