The NUP214::ABL1 fusion is the second most common translocation involving the gene ABL1, after BCR::ABL1. It is a cryptic fusion in conventional karyotype, but detectable by molecular methods with specific probes. 8 It can be seen in B cell acute lymphoblastic leukemia (ALL) and less common in T cell ALL. 9,10 ABL1-a tyrosine kinase protein-is localized in 9q34.13 and NUP214-a component of the nuclear pore complex-in 9q34.12. There is a model that NUP214::ABL1 formation comes from a circularized region that segregated unequally during cellular division. 8 It is included in the Ph-like ALL group and may benefit from the use of tyrosine kinase inhibitors (TKI) such as dasatinib. [11][12][13] It is not seen among AML patients. There is just one previous case of NUP214::ABL1 in a 42-year-old patient in China. 14 This is the second description of the NUP214::ABL1 rearrangement found in AML, the first in the pediatric population. The lack of molecular methods availability impairs AML stratifying and this case was only better elucidated with the NGS on relapse. Even if other methods like protein chain reaction or fluorescence in situ hybridization were available, in this case, it hardly would be more enlightening, as this fusion is not routinely screened in AML. Moreover, his final classification is still defined by differentiation, as it is not otherwise specified. Perhaps there will be more cases described in the future, as the molecular tools become more accessible. Collecting cases like this one is extremely important for better understanding and discussing target therapies in future. The benefit of the use of TKI in this case remains an unanswered question. The more the stratifying tools are available worldwide, the better we will be able to personalize treatment. ACKNOWLEDGMENTSThe family gave written informed consent for archiving material in a biobank, for molecular profiling and clinical studies. It has the approval by the Ethics Committee of Federal University of São Paulo.

No abstract