RBCK1-TRIB3 decelerated the progression of acute promyelocytic leukemia.

Under the differentiation induction therapy with all-trans retinoic acid and arsenic trioxide, nearly 95% of typical acute promyelocyte leukemia (APL), which is characterized by the presence of PML-RARA, patients can be cured. Though its good prognosis, if left untreated, the natural survival duration of typical APL patients is only 1 month, but some exceptional cases also exist. Occasionally, we have observed the entire natural clinical course of one extremely indolent APL patient, who developed from pre-APL stage (<20% promyelocytes in bone marrow) to overt-APL stage (≥20% promyelocytes in bone marrow) with one nearly 2-year latency. Strikingly, we identified one novel fusion RBCK1-TRIB3 in the pre-APL stage but not overt-APL stage sample. It has been reported that TRIB3 stabilized PML-RARA to driver APL progression, while RBCK1-TRIB3 partially disrupted TRIB3 expression, so it contributed to the deceleration of APL progression in this patient.