Likewise, examining whether the down-modulation of NKG2D was dependent on exosome phenotype, a previous study found that exosomes isolated from NKG2D ligand-positive tumor cells, including mesothelioma cell line, prostate cell lines (PC3 or DU145), EBV-B lymphoblastoid cells (IB4), or exosomes purified from a mesothelioma patient’s pleural fluid (PF) were capable of driving down the expression of NKG2D in NK cells [78]. This evidence concerns the gene KLRK1 and mesothelioma.