Objectives: Tumorigenesis is a multistep process that begins with the abrogation of normal controls of apoptosis and cell proliferation, and the Fas receptor-ligand system is a key regulator of apoptosis. The Fas -670 A/G single-nucleotide polymorphism (SNP) has been demonstrated to affect the expression of the Fas gene by altering the transcriptional activity in this gene's promoter. However, the association between the Fas -670 A/G polymorphism and digestive cancer risk is still controversial and ambiguous in the Asian population, so we conducted a meta-analysis to confirm and clarify the association between the Fas -670 A/G polymorphism and digestive cancer.
Materials and methods: A search of PubMed, China National Knowledge Infrastructure (CNKI), and WanFang databases was conducted and encompassed all available articles that had been published up to July 20, 2013. Overall, 15 case-control studies containing 3692 cases and 4895 controls were retrieved based on search criteria for digestive cancer susceptibility related to -670A/G SNP. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of this association.
Results: In the overall analysis, the country type and source of control subgroups, no association between the Fas -670 A/G polymorphism and digestive cancer risk was found. However, in the digestive cancer-type subgroups, a significant protective effect was detected between Fas -670 A/G polymorphism and hepatocellular carcinoma in Asians (AG vs. GG: OR=0.89, 95% CI=0.80-0.99; AA+AG vs. GG: OR=0.93, 95% CI=0.87-1.00).
Conclusions: Our investigations demonstrated that the Fas -670 A/G polymorphism might decrease the hepatocellular carcinoma risk in Asian populations. Further studies based on larger sample sizes, other ethnicities, and gene-environment interactions should be conducted to further understand the role of Fas -670 A/G polymorphism in digestive cancer risk.