A complex translocation (1;17;15) with spliced short-type PML-RARA fusion transcripts in acute promyelocytic leukemia: A case report

The promyelocytic leukemia (PML)-retinoic acid receptor α (RARA) fusion is hypothesized to serve a vital role in the pathogenesis of acute promyelocytic leukemia (APL), which results from a reciprocal translocation between chromosomes 15 and 17, t(15;17)(q24;q21). A minority of APL cases lack the classical t(15;17) and have been identified to have cryptic or masked t(15;17) or complex translocations. The present study reports on a case of a 37-year-old male with APL harboring a complex three-way translocation t(1;17;15)(q21;q21;q24). This karyotypic interpretation was further confirmed by fluorescence in situ hybridization, and 98% of the bone marrow cells analyzed were positive for the PML-RARA fusion gene. After combined treatment with all-trans retinoic acid and arsenic trioxide, the patient achieved complete remission with no recurrence for 3 years to date. To the best of our knowledge, the present study is the first to report on the novel variant of t(15;17) involving the breakpoint 1q21.