LMO2 (LIM domain only 2) is a transcription regulator that plays critical roles in hematopoietic development and oncogenesis. In normal hematopoiesis, LMO2 functions as part of a heptad of transcription factors (FLI1, ERG, GATA2, RUNX1, TAL1, LYL1, LMO2) that bind regulatory elements in hematopoietic stem and progenitor cells (HSPCs) 1. LMO2 cooperates with TAL1 to regulate erythroid differentiation and works with LDB1 to maintain erythroid precursors in immature states 2. Mechanistically, LMO2 functions through multi-enhancer networks established by LDB1, which promotes connectivity among regulatory elements to activate transcription 3. LMO2 is frequently dysregulated in T-cell acute lymphoblastic leukemia (T-ALL) through chr11 translocations, serving as a paradigmatic oncogene 4. In pediatric γδ T-ALL, LMO2 alterations combined with STAG2 inactivation represent extremely high-risk disease 5. LMO2 also promotes quiescence in leukemia-initiating cells, contributing to chemotolerance 6. Beyond hematologic malignancies, LMO2 expression in breast cancer marks angiogenic tumor cells that promote metastasis through STAT3 signaling 7, while in primary CNS lymphoma, LMO2 expression correlates with improved survival 8.