PROS1 and neoplasm: In view of the therapeutic properties of NK92 cell exosomes, researchers have modified the exosome surface proteins, combined them with single-chain antibodies recognizing tumor-associated antigens, and established the exosome surface display technology of single-chain antibodies to tumor-associated antigens, which enhances the broad-spectrum tumor targeting of the exosomes or the targeting of specific tumor cells or improves the therapeutic efficacy of antitumor drugs through the endogenous overexpression of effector molecules in the cells (185).