In conclusion, several studies have shown that some KIR genes (e.g., KIR2DS5, KIR2DS1, KIR3DS1) are associated with an increased risk of developing CRC, while others (e.g., KIR2DS4, KIR3DL1) might have a protective role. This evidence concerns the gene KIR3DL1 and colorectal carcinoma.