NK cells from CRC patients exhibit reduced levels of activating NK cell receptors such as NKG2D, DNAM-1, NKp30, NKp44, NKp46 and cytotoxic perforin, and elevated levels of inhibitory receptors like NKG2A, CD85j and KIR3L1, indicating a diminished functionality [45,46,47]. This evidence concerns the gene PRF1 and colorectal carcinoma.