Acute Promyelocytic Leukemia with del(6)(p22) and Atypical bcr2 <b><i>PML</i></b>::<b><i>RARA</i></b> Fusion Transcript: A Case Report

Abstract

More than 95% of patients with acute promyelocytic leukemia (APL) are characterized by the reciprocal translocation t(15;17)(q24;21), which involves the promyelocytic leukemia protein (<i>PML</i>) gene on chromosome 15 and the retinoic acid receptor-α (<i>RARA</i>) gene on chromosome 17, leading to the production of the <i>PML</i>::<i>RARA</i> chimeric gene. Additional chromosomal abnormalities are described in all acute myeloid leukemias and occur in approximately one-third of patients with newly diagnosed APL. Here, we report the case of de novo APL showing the classical t(15;17)(q24;q21), a deletion of the short arm of chromosome 6 (6p), and a noncanonical molecular variant of the <i>PML</i>::<i>RARA</i> transcript. Nevertheless, the patient achieved complete remission after treatment with conventional therapy with all-trans retinoic acid (ATRA) and arsenic trioxide (ATO). Notwithstanding that the molecular pathogenesis of this type of atypical variant still remains unknown, we conclude that this atypical <i>PML</i>::<i>RARA</i> bcr2 fusion gene associated with del(6p) does not seem to alter the effectiveness of combined treatment with ATRA and ATO.