3D chromosome remodeling in B-cell development and acute lymphoblastic leukemia

The identification of molecular subgroups of pediatric B-cell acute lymphocytic leukemia (B-ALL) has proven to be a powerful tool in understanding disease pathogenesis and treatment stratification. Studies have suggested aberrant transcription factor function and epigenetic regulation can explain differences between B-ALL subtypes, however, the impact of 3D genome re-organization remains unclear. Here we used in situ Hi-C and RNA-seq to profile the chromatin architectural landscape in healthy B-cell progenitors and B-ALL patient samples harboring prognostically relevant structural variations, including ETV6::RUNX1, KMT2A::AFF1, and BCR::ABL. We showed that B-ALLs undergo subtype-specific changes that, in part, reflect the differentiation stage of the disease, and that they acquire aberrant chromatin configurations that allow expression of oncogenic drivers. One such driver, ERG, displayed increased interactivity and expression in ETV6::RUNX1 B-ALL, and evidence suggests it plays a role in regulating survival and differentiation. Overall, these results underscore the essential role of 3D nuclear organization in acute leukemia.