+49G > A polymorphism in the cytotoxic T-lymphocyte antigen-4 gene increases susceptibility to hepatitis B-related hepatocellular carcinoma in a male Chinese population.

Cytotoxic T-lymphocyte antigen 4 (CTLA-4) is an important regulator and functions negatively in immune response. Its nonsynonymous polymorphism +49G > A (dbSNP: rs231775) has been linked to an elevated risk of T-cell-mediated autoimmune diseases, infectious diseases, and even carcinomas. Here, we examined the genotypes at rs231775 of 1003 subjects in a Han Chinese population to detect the association between this single-nucleotide polymorphism (SNP) and hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) susceptibility, including 375 HBV-related HCC patients, 209 non-HCC patients with HBV infection, and 419 healthy controls. Our results indicated a weak trend for the relationship between rs231775 and HBV-related HCC susceptibility, although the statistical level was not significant. However, a significant difference was identified in males between HBV-related HCC patients and healthy controls. The data revealed that the frequency of the A/A genotype was higher in patients compared with healthy controls (odds ratio [OR] = 1.79, 95% confidence interval [95% CI] 1.05-3.08). The G allele appeared to have a protective effect in developing HBV-related HCC. Subjects with the A allele had higher HCC susceptibility than those with the G allele (OR = 1.31, 95% CI 1.03-1.66). These results suggested that the A/A genotype and A allele of rs231775 increased the risk of developing HBV-related HCC in a male Chinese population.