Importantly, we show here that prostate tumor-derived exosomes are most likely involved in downregulation of NKG2D in PC patients, as incubation of healthy lymphocytes with exosomes isolated from serum or plasma (data not shown) of CRPC patients triggered downregulation of NKG2D expression in effector lymphocytes. This evidence concerns the gene KLRK1 and pachyonychia congenita.