Independent and additive interaction between polymorphisms of tumor necrosis factor α−308 and lymphotoxin α+252 on risk of hepatocellular carcinoma related to hepatitis B

Abstract

This case–control study was aimed to assess the effect of genetic variants of tumor necrosis factor (TNF) α−308 and lymphotoxin (LT) α+252 on development of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). Their gene–gene interaction was also investigated. We enrolled 200 pairs of age- and sex-matched patients with cirrhotic HBV-HCC and unrelated patients with HBV-cirrhosis alone. Polymorphisms of TNFα−308 and LTα+252 were genotyped. Synergy index was used to calculate interaction between the variant genotypes. The results indicated that the frequency distribution of the variant genotypes (TNFα−308 G/A and LTα+252 G/G) in patients with HCC were significantly higher than those in patients with cirrhosis alone. Multivariate analysis indicated that TNFα−308 G/A (odds ratio [OR], 2.34) and LTα+252 G/G (OR, 2.04) were independent risk factors for HCC. By the clinical characteristics of study population, multivariate analysis demonstrated that independent factors associated with harboring the variant genotypes included cirrhosis with Child-Pugh C (OR = 6.47 in cases and OR = 11.56 in controls) and thrombocytopenia (OR = 8.86 in cases and OR = 7.74 in controls). Calculation of synergy index (SI) indicated that there are additive interaction between TNFα−308 G/A and LTα+252 G/G on risk of HCC (SI = 1.29). In conclusion: There are independent and additive interactions between TNFα−308 G/A and LTα+252 G/G on risk for HBV-HCC. They correlated with advanced hepatic fibrosis and severe liver damage, which might contribute to a higher risk for HCC.

Keywords

• Hepatitis B related hepatocellular carcinoma
• Lymphotoxin α
• Single nucleotide polymorphism
• Synergy index
• Tumor necrosis factor α