Indeed, an International Society for Extracellular Vesicles position paper has specifically highlighted the problematic nature of polymer precipitation methods in EV research as these kits “do not exclusively isolate EVs, and are likely to co-isolate other molecules, including miRNA-protein complexes.”46 For instance, polymer precipitation methods of EV purification have been shown to co-purify vesicle-free miRNAs from rat plasma47 and non-vesicular extracellular Argonaute-2 complexes from the secretome of MCF-7 breast cancer cell cultures.43 Here, AGO2 is linked to breast cancer.