CD8A and neoplasm: Anti-CD8α mAbs were covalently attached to the surfaces of the EV-MAP with an oligonucleotide bifunctional linker (Fig. 2a)24, which contained a uracil residue that can be cleaved with USER® (Uracil Specific Excision Reagent) hence allowing for release of EVs after affinity enrichment, similar to what we have shown for affinity-enriched circulating tumor cells24.