Value of Oligonucleotide-Based Array Comparative Genomic Hybridization for Diagnosis of Acute Promyelocytic Leukemia in a Patient Negative for t(15;17)(q24.1;q21.2)/Promyelocytic Leukemia-Retinoic Acid Receptor, Alpha by Conventional Cytogenetics and Fluorescence In Situ Hybridization

Abstract

Acute promyelocytic leukemia (APL) is characterized by promyelocytic leukemia (PML)-retinoic acid receptor, alpha (RARA) fusion gene as a result of t(15;17)(q24.1;q21.2).1 Current advances in APL therapy have dramatically improved patient outcome.2,3 However, patients with APL are at risk of potentially lethal coagulopathy if appropriate therapy is delayed.4 The t(15;17)(q24.1;q21.2) is detected using conventional cytogenetic analysis in approximately 90% of APL cases.5,6 A small subset of APL cases (4%) lack the classical t(15;17)(q24.1;q21.2) and have other complex translocations.1,2 Rare APL cases have submicroscopic insertions of PML or RARA, in which reverse transcription (RT) polymerase chain reaction (PCR) detects PML-RARA transcripts and yet conventional cytogenetics and fluorescence in situ hybridization (FISH) results are negative.1,5,7–9