To address this knowledge gap, we mapped chromatin accessibility in fresh primary ALL cells from 156 patients across ten molecular subtypes of B-ALL (BCR::ABL1, DUX4-rearranged, ETV6::RUNX1, high hyperdiploid, low hypodiploid, KMT2A-rearranged, BCR::ABL1-like [Ph-like], PAX5-altered, TCF3::PBX1, and ZNF384-rearranged) and B-other patient samples. This evidence concerns the gene KMT2A and acute lymphoblastic leukemia.