Information transfer by exosomes: A new frontier in hematologic malignancies

Exosomes are small (30–150 mm) vesicles secreted by all cell types and present in all body fluids. They are emerging as vehicles for delivery of membrane-tethered signaling molecules and membrane enclosed genes to target cells. Exosome-mediated information transfer allows for crosstalk of cells within the hematopoietic system and for interactions between hematopoietic cells and local or distant tissue cells. Exosomes carry physiological signals essential for health and participate in pathological processes, including malignant transformation. In hematologic malignancies, exosomes reprogram the bone marrow microenvironment, creating a niche for abnormal cells and favoring their expansion. The molecular and genetic mechanisms exosomes utilize to shuttle information between cells are currently being examined as are the potential roles exosomes play as biomarkers of disease or future therapeutic targets.