Interestingly, although the data in this field of research remain controversial, it has been recently shown that the same SNPs in the CTLA-4 coding region are also associated with susceptibility to human cancer [36], such as cervical squamous cell carcinoma [37], colorectal cancer [38], hepatocellular carcinoma [39], gastric cancer [40] and acute myeloid leukemia [41]. Here, CTLA4 is linked to cancer.