EBF1 (EBF transcription factor 1) is a DNA-binding transcription factor that regulates gene expression across multiple biological contexts. In B cell development, EBF1 plays a critical role in lineage commitment and differentiation, with reciprocal changes in EBF1 expression marking the transition between pre-BCR-dependent and pre-BCR-independent proliferative phases 1. EBF1 is a lineage-specification gene whose transcription is regulated by the cohesin complex member STAG2; loss of Stag2 decreases EBF1 chr5 accessibility and transcription, impairing B cell lineage commitment 2. Beyond hematopoiesis, EBF1 functions as a transcriptional regulator of adipocyte morphology and brown adipogenesis, with genetic variation in EBF1 identified as a locus associated with epicardial and pericardial adiposity and related cardiovascular disease risk 3. EBF1 is also expressed in dermal papilla fibroblasts, where it activates regulatory networks controlling hair morphogenesis in response to Hedgehog signaling 4. In disease contexts, EBF1 deletions occur as secondary copy number alterations in B-cell precursor acute lymphoblastic leukemia, though individual EBF1 deletions show limited independent prognostic significance compared to primary chr5 abnormalities 5. Additionally, EBF1+ fibroblasts represent a distinct population identified during postnatal liver development 6.