A new three-way variant t(15;22;17)(q22;q11.2;q21) in acute promyelocytic leukemia

Abstract

Acute promyelocytic leukemia (APL) is characterized by the t(15;17)(q22;q21), which results in the fusion of the promyelocytic leukemia (PML) gene at 15q22 with the retinoic acid alpha-receptor (RARA) at 17q21. We report the case of a 44-year-old man with APL carrying a new complex variant translocation (15;22;17). Karyotypic analysis with G-banding of bone marrow cells revealed t(15;22;17) (q22;q11.2;q21). Fluorescence in situ hybridization with a PML/RARA dual-color DNA probe showed the fusion signals. RT-PCR analysis showed long-form PML/RARA fusion transcripts. A complete remission was attained with a course of conventional chemotherapy with all-trans retinoic acid (ATRA). This is the first report of a new three-way translocation of 22q11 involvement with APL.

A three‑way complex translocation of (15;15;17)(q24;q14;q21) involving two breakpoints on chromosome 15 in acute promyelocytic leukemia: A case report

“…The prognostic course of patients with a complex variant of t(15;17) does not differ from that of patients with the typical t(15;17) as long as the PML::RARa fusion is intact. According to the literature (5,6,12,13,18), almost all patients with APL involving variant translocations have a good response to ATRA treatment. The patient in the present study has thus far also had a good response to ATRA.…”

“…The fusion gene PML::RARa is created on derivative chromosome 15 and the fusion transcript are hypothesized to play a serve role in the pathogenesis of APL (4). Third or fourth breakpoints in three-way or more complex translocations have been reported, but they are likely to occur recurrently in particular chromosome bands, such as 1q36, 11q3, 2q21, 3p21, 4q21, 6q23, 19p13, 20p13, and Xq13 (5). However, a third breakpoint on the same chromosome 15 involved in the classical t(15;17)(q24;q21) defect is extremely rare, with only one case reported to date, to the best of the author's knowledge (6).…”

Coexistence of t(15;17) and t(15;16;17) detected by fluorescence in situ hybridization in a patient with acute promyelocytic leukemia: A case report and literature review

“…To the best of our knowledge, 45 cases have been reported (5,6,9,11–40), which account for 10% of APLs lacking classical t(15;17) (6). The clinical characterizations of the reported cases of APL with ct(15;17;v), including the present study, are summarized in Table I.…”

“…While 168 out of 200 cells (84%) exhibited one fusion signal, two SpectrumOrange signals and two SpectrumGreen signals, which were the result of the complex variant translocation, t(15;16;17) (Fig. 1C) (9). By combining the karyotyping and FISH results, it was demonstrated on metaphase cells that a part of the PML gene labeled with SpectrumOrange was present on the derivative chromosome 16 and a part of the RARA gene labeled with SpectrumGreen signal was present on the derivative chromosome 17 (Fig.…”