CD9 and cancer: Specific antibodies for targeting EV biomarkers, such as CD63, CD9, and CD81, are popular tools in EV capture, while antibodies targeting cancer‐specific membrane proteins, such as EpCAM, EGFR, and GPC‐1, are also frequently used in cancer‐derived EV isolation.[90, 91, 92] It is worth noting that only antibodies that bind to the extracellular domain of EV membrane proteins are suitable for EV isolation.