MEIS1 (Meis homeobox 1) is a transcription factor that plays critical roles in hematopoiesis, cardiovascular development, and cancer. As a member of the TALE family of homeodomain proteins, MEIS1 functions by binding DNA in a sequence-specific manner and forming cooperative complexes with other transcription factors, including HOX proteins and PBX cofactors 1. In hematopoiesis, MEIS1 is essential for maintaining leukemic stem cells, with overexpression observed in acute myeloid leukemia (AML) and acute lymphoblastic leukemia, particularly in cases with MLL rearrangements or NPM1 mutations 234. The protein maintains leukemic states through sustained HOX gene expression, making it a target for menin inhibitor therapies that disrupt MEIS1-dependent pathways 5. In cardiovascular biology, MEIS1 regulates cardiomyocyte proliferation and regeneration, with studies showing that Meis1 inhibition can enhance cardiac repair following myocardial infarction 67. Additionally, MEIS1 has been implicated in colorectal cancer, where its downregulation promotes tumorigenesis and oxaliplatin resistance through enhanced DNA repair mechanisms 8. These diverse functions establish MEIS1 as a key regulator of cell fate decisions across multiple organ systems.