A new four-way variant t(5;17;15;20)(q33;q12;q22;q11.2) in acute promyelocytic leukemia.

Acute promyelocytic leukemia (APL) is characterized by 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 a patient with APL carrying a new complex variant translocation (5;17;15;20). Spectral karyotyping analysis of bone marrow cells revealed t(5;17;15;20)(q33;q12;q22;q11.2). Fluorescence in situ hybridization with a PML/RARA dual-color DNA probe showed a single fusion signal, and RT-PCR analysis showed PML/RARA fusion transcripts. Complete remission was attained with a course of conventional chemotherapy with all-trans retinoic acid (ATRA). To our knowledge, this is the first report of a four-way translocation of 5q33 and 20q11 involvement in APL.