CTLA4 and colorectal cancer: There are numerous reports assessing the association between CTLA-4 genotypes and cancer risk: +49A/G SNP has been found in breast, esophageal, gastric and colorectal cancers, oral squamous cell carcinoma, and osteosarcoma [17, 27–31], while −318C/T SNP, although less frequently analyzed, has also revealed associations with breast, cervical, gastric and colorectal cancers, and B-cell chronic lymphocytic leukemia [29, 32–35].