Apart from these classical markers, surface antigens such as epithelial cell adhesion molecule (EpCAM), EGFR, integrins (e.g., α6β4, αvβ5), and even PD-L1 have been used for immunoaffinity capture of tumor-derived exosomes, significantly improving specificity and reducing contamination from non-vesicular particles or lipoproteins [199]. Here, CD274 is linked to neoplasm.