PRF1 and neoplasm: NK3.3-derived EVs also contained cytotoxic proteins required for NK anti-tumor activity: NKLAM, perforin, granzymes A and B, and granulysin, as well as immune-associated proteins MHC I and II and DNAX Accessory Molecule (DNAM-1; CD226), an activating receptor on NK cells (Neviani et al., 2019).