Transforming growth factor β1-509C/T and +869T/C polymorphisms on the risk of upper digestive tract cancer: a meta-analysis based on 10,917 participants

Abstract

The aim of this study was to assess the relationships between transforming growth factor β1-509C/T (rs1800469) and +869T/C (rs1800470) polymorphisms and the risk of upper digestive tract cancer (UDT cancer) by using a meta-analysis. We interrogated the databases of Medline, Embase and Wanfang (Chinese literature database) (latest update; December 15, 2011). Odds ratios (OR) and corresponding 95% confidence intervals (95% CI) were used to assess the strength of the associations. In total, 20 case-control studies were included in this meta-analysis. Overall, both TGF β1-509C/T and +869T/C polymorphisms were not associated with risk of UDT cancer [-509C/T: OR (95%CI) = 1.10 (0.99-1.22) for TT vs. C carries, P(heterogeneity) = 0.10; +869T/C: OR (95%CI) = 1.04 (0.88-1.23) for CC vs. T carriers, P(heterogeneity) = 0.02]. Subgroup analyses indicated that the -509T allele was associated with increased risk of UDT cancer in population-based studies (OR = 1.16 (1.04-1.31), P(heterogeneity) = 0.31 for TT vs. C carriers) and in small sample-sized studies (OR = 1.45 (1.15-1.84), P(heterogeneity) = 0.56 TT vs. C carriers). All subgroup analyses for the TGF β1+869T/C polymorphism indicated null association except for hepatocellular carcinoma. Interestingly, both the TGF β1-509T allele and the +869C allele were associated with decreased risk of hepatocellular cancer based on limited original studies. This meta-analysis indicated that TGF β1-509C/T rather than +869T/C is a potential risk factor for UDT cancer.