Objective: To report a rare variant of t(15;17), ins(17;15)(q21;q14q22) in an acute promyelocytic leukemia (APL) patient and the results of cytogenetic and molecular genetic studies.
Methods: Chromosomes were prepared after 24 hours culture of bone marrow cells and peripheral blood cells. R-banding technique was used to analyze karyotypes. Chromosome painting analysis was performed using whole chromosome paints for chromosomes 15 and 17. PML-RAR alpha and RAR alpha-PML fusion transcripts were detected by reverse transcription-polymerase chain reaction (RT-PCR).
Results: Karyotypic analysis using both specimens from bone marrow and peripheral blood leukemic cells revealed 15q- and 17q+. Chromosome painting analysis confirmed that the karyotypic abnormality was ins(17;15). PML-RAR alpha fusion transcript (S type) was detected by RT-PCR, while RAR alpha-PML fusion transcript was not detected.
Conclusion: Chromosome painting and RT-PCR are reliable methods for characterization of the insertion involving chromosomes 15 and 17 in APL patients.