Updated project metadata. Leukemia cells instruct their surrounding bone marrow microenvironment (BMM) rendering it hospitable to leukemia cell survival. Conversely, how cells of the BMM influence leukemia progression is less well understood. Pleckstrin homology domain family M member 1 (PLEKHM1) serves as a hub between fusion and secretion of intracellular vesicles. Here, we performed label-free quantitative proteomics to investigate the exosomal cargo released by BMM-derived mesenchymal stromal cells (MSC) lacking Plekhm1 compared to wild-type cells.