Human CEBPA -N AML exhibits enhanced engraftment and a C/EBP α -p30-driven leukemic stem cell program.

Leukemic stem cells (LSCs) play a central role in disease progression, therapeutic resistance, and relapse in acute myeloid leukemia (AML). However, the identification and characterization of LSCs remain challenging because of their low abundance and their close phenotypic resemblance to normal hematopoietic stem and progenitor cells. Although patient-derived xenograft (PDX) models have provided important insights into AML biology and LSC heterogeneity, the relative engraftment potential of distinct CEBPA mutation subtypes and the immunophenotypic identity of LSCs in CEBPA N-terminal mutant AML ( CEBPA - N -AML) remain poorly defined. To address these questions, we compared the engraftment characteristics of primary human CEBPA-mutated AML samples representing the major mutational subtypes using the highly permissive NSGS xenograft model. Primary CEBPA -N-AML samples exhibited markedly greater engraftment efficiency and leukemogenic potential than other CEBPA -mutated AML subtypes. Furthermore, we identified a CD366⁺CD73⁺CD123⁺CD117⁺CD371⁺CD247⁺ cell population that is highly enriched for functional LSCs in CEBPA-N -AML, demonstrating enhanced clonogenic activity, leukemia-initiating capacity, and long-term self-renewal. Collectively, our findings demonstrate that the leukemogenic potential of CEBPA -mutated AML is strongly influenced by mutation subtype, with CEBPA-N -AML exhibiting superior leukemia-propagating capacity in vivo. We further define a novel immunophenotypic LSC signature specific to CEBPA-N -AML, providing new insights into LSC heterogeneity in CEBPA -mutated AML and establishing a foundation for the development of LSC-directed therapeutic strategies.