Microvesicles (100–1000 nm), formed by membrane budding and cytoskeletal rearrangement, are particularly enriched in chemoresistant HNSCC cells and carry functional efflux pumps such as P-glycoprotein and DNA repair proteins like ERCC1 (3, 4, 17). The gene discussed is ERCC1; the disease is head and neck squamous cell carcinoma.