Lazarenkov, A.; Valcarcel, G.; Martinez, A.; Berenguer, C.; Lopez-Rubio, A. V.; Obiols, M.; Fontanet, C.; Rodriguez-Sevilla, J. J.; Stik, G.; Jeremias, I.; Menendez, P.; Sardina, J. L.

DNA methylation dynamics shape hematopoietic differentiation and leukemogenesis; yet how the dioxygenase TET2, frequently mutated in myeloid malignancies, directs lineage-specific regulatory programs remains unclear. Here, we integrated DNA methylation, chromatin accessibility, 3D genome architecture, transcriptional profiling, and TET2 chromatin occupancy to define TET2-dependent control of human myeloid commitment. We found that TET2-bound regulatory regions gain short- and long-range chromatin interactions, and that a distinct subset of distal, enhancer-enriched sites undergoes TET2-driven demethylation and activation. Among these, we identified an AGO2 myeloid-specific intragenic enhancer that is frequently hypermethylated in TET2-mutant AML patients. AGO2 expression stratifies patient survival, and AGO2 depletion abrogates leukemic engraftment in vivo. These findings uncover a TET2 to AGO2 regulatory axis that integrates epigenetic remodeling, 3D genome reorganization, and leukemic fitness, and they highlight AGO2 as a potential biomarker and therapeutic target in myeloid leukemia.