Association between transforming growth factor-β1 -509 C>T variants and hepatocellular carcinoma susceptibility: a meta-analysis

The transcriptional activity of transforming growth factor-β (TGF-β) is increased in subjects with hepatocellular carcinoma (HCC). Recent studies have indicated that the -509C genotype in hepatitis B virus (HBV)-infected subjects and the -509T genotype in hepatitis C virus (HCV)-infected subjects can increase the transcriptional activity of the TGF-β1 gene. We conducted a meta-analysis to clarify whether these two hepatitis viruses affect the association between TGF-β1 C-509T variants and HCC susceptibility. Using data derived from 8 case-control studies available in the PubMed database (5 with Asian and 3 with Caucasian populations), including 1,427 cases and 3,735 controls [1,610 patients with chronic liver disease and 2,125 healthy controls], we calculated pooled odds ratios with corresponding 95% confidence intervals. We used dominant (TT + CT vs. CC), recessive (TT vs. CC + CT), and co-dominant (TT vs. CC and CT vs. CC) genetic models. An overall analysis showed no association between the TGF-β1 C-509T variants and HCC susceptibility for all models. In contrast, a subgroup analysis, based on the infecting hepatitis viruses, provided the following results. Among the cases and controls with chronic liver disease, the TGF-β1 C-509T variants were significantly associated with decreased HCC susceptibility for two models with HBV-infected subjects, whereas the variants were significantly associated with increased HCC susceptibility for one model with HCV-infected subjects. Among the cases and healthy controls, there was a significant association between the TGF-β1 C-509T variants and increased HCC susceptibility for two models involving HCV-infected subjects. Among the cases and the entire control group, the same results were obtained for all genetic models with HCV-infected subjects. Although further data accumulation is required, our results suggest that these two hepatitis viruses affect the association between TGF-β1 C-509T variants and HCC susceptibility in opposite manners.