Extracellular vesicles are tiny membrane bound particles released by nearly all cell types into body fluids such as blood, urine and saliva. They include exosomes, microvesicles and apoptotic bodies, which differ mainly in size and how they are formed. Once thought to be cellular waste, they are now recognized as active messengers that transfer proteins, lipids and nucleic acids between cells.

Research shows that extracellular vesicles can reflect the molecular state of their cells of origin. Tumor cells, for example, release vesicles carrying oncogenic proteins and RNAs that can promote cancer growth, support angiogenesis and help tumors evade the immune system. Because of this, vesicles in blood or other fluids are being investigated as non invasive biomarkers for early detection, prognosis and monitoring of cancer and other diseases such as neurodegenerative and cardiovascular disorders.

Their natural ability to protect and deliver cargo has also made extracellular vesicles attractive as therapeutic tools. Studies are exploring vesicles derived from stem cells for tissue repair and modulation of inflammation, and engineered vesicles as carriers for drugs, small RNAs or gene editing components targeted to specific tissues.

A major challenge is standardization. Isolation and characterization methods vary widely, affecting reproducibility and interpretation of results. International efforts are underway to harmonize protocols and reporting criteria, improve purity and scalability of vesicle preparations, and clarify nomenclature. As these technical issues are addressed, extracellular vesicles are expected to play an increasingly important role in diagnostics, prognostics and targeted therapies across many areas of medicine.