Acute promyelocytic leukemia with del(6)(p22) and atypical bcr2 PML::RARA fusion transcript: a case report

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 (PML) gene on chromosome 15 and the retinoic acid receptor-alpha (RARA) gene on chromosome 17 leading to the production of PML::RARA 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 non-canonical molecular variant of the PML::RARA 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 PML::RARA bcr2 fusion gene associated with del(6p) does not seem to alter the effectiveness of combined therapy with ATRA and ATO.

Automated summary

The majority of patients with acute promyelocytic leukemia (APL) have a specific genetic translocation t(15;17)(q24;21), but this case report describes a rare variant of the PML::RARA fusion gene. However, the patient achieved complete remission after standard treatment, suggesting that this atypical variant does not affect the effectiveness of combined therapy with ATRA and ATO.