CD8A and neoplasm: Recent studies suggest that tumor cells induce direct cytotoxic effects on T cells by releasing exosomal proteins and RNA.171,172 For example, exosomes released by head and neck cancer-derived cell lines induce CD8+ T cell suppression, further impairing the antitumor immune response.173 Mass spectrometry analysis revealed that exosomes with immunosuppressive activity are enriched with the immune regulatory protein galectin-1.