TCF3 and acute lymphoblastic leukemia: B-ALL/LBL with ETV6::RUNX1-like features (considered provisional by the ICC) is identified by its gene expression profile and usually is driven by fusions or copy number alterations of ETV6, FUS or IKZF1. It may have worse prognosis than B-ALL/LBL with ETV6::RUNX1. B-ALL/LBL with TCF3::HLF fusion (WHO-HAEM5) /B-ALL/LBL with HLF rearrangement (ICC) is a rare entity occurring almost exclusively in children, with very poor prognosis.