BCL9 and leukemia: In the same line, some of the most recurrent fusion genes in pediatric leukemia were found in our cohort (ETV6::RUNX1, STIL::TAL1, KMT2A-rearrangements, RUNX1::RUNX1T1, BCR::ABL1), as well as other novel rearrangements described, most of them associated with BCP-ALL B-other subtypes (MEF2D::BCL9, MEF2D::CSF1R, ETV6::ABL1, TCF3::ZNF384, and PAX5::NOL4L) or to rare and/or recent AML fusions reported in the literature (RUNX1::CBFA2T3, RBM15::MKL1, RUNX1::USP42, and TBL1XR1::TP63) (Medinger and Passweg, 2017; Schwab and Harrison, 2018; Inaba and Mullighan, 2020).