Identification of a novel RAB6A::TOP2A fusion in acute non-promyelocytic leukemia harboring t(11;17)(q13;q21) translocation.

Fusion genes generally serve as driver mutations in leukemia. The rearrangement of the RARA gene located on chromosome 17q21 is a molecular pathological feature of acute promyelocytic leukemia (APL). A series of RARA-involved fusion genes have been identified in variant APL, including one carrying the t(11;17)(q13;q21) translocation, resulting in the NUMA1::RARA fusion gene. Here, we present an interesting case where blasts carry the t(11;17)(q13;q21), but the cell morphology does not exhibit signs of promyelocytic differentiation. Transcriptome sequencing identified a novel fusion gene, RAB6A::TOP2A, with a frameshift mutation in the reading frame. The patient did not respond to all-trans retinoic acid (ATRA) treatment.