CTLA-4+49A>G polymorphism is associated with the risk but not with the progression of colorectal cancer in Chinese

Colorectal cancer (CRC) is one of the most common malignancies in the world and a multipathway disease. Cytotoxic T-lymphocyte antigen-4 (CTLA-4) is a potent immunoregulatory molecule that suppresses antitumor response by down-regulating T-cell activation. The most studied +49A > G polymorphism of CTLA-4 gene has been associated with several autoimmune or cancer diseases. Our aim was to investigate the association between this genetic variant and the risk as well as progression of colorectal cancer in Chinese. We conducted a case-control study of 124 colorectal cancer cases and 407 healthy controls. DNA was extracted from blood specimens, and +49A > G polymorphism in the CTLA-4 gene was genotyped by polymerase chain reaction-ligation detection reaction (PCR-LDR). In our study group, the frequency of AG or GG or carrying at least one G allele at position +49 was significantly different in colorectal cancer patients and the control group, indicating that the risk of CRC was significantly higher among subjects with the AG or GG genotype or carrying at least one G allele at position +49 than among the subjects with the AA genotype. However, we observed no association between CTLA-4 +49A > G polymorphism and the progression of CRC. Interestingly, the CTLA-4 +49A allele was in non-significantly higher numbers in CRC patients with distant metastasis. Our results suggested that CTLA-4 +49A > G polymorphism was associated with an increased risk of colorectal cancer, but this polymorphism did not play an important role in the progression of CRC in Chinese.