Association between the -607 C > A polymorphism in interleukin-18 gene promoter with gastrointestinal cancer risk: A meta-analysis

Abstract

The interleukin-18 (IL-18) gene -607 C/A polymorphism has been reported to be associated with gastrointestinal cancer, but there are conflicting results from previous studies on said topic. Therefore, the aim of this meta-analysis is to derive a more precise estimation of the association between the -607 C/A polymorphism in the IL-18 gene and gastrointestinal cancer risk. Literature searches of PubMed, Google Scholar, and Web of Science databases were carried out in 2015. Five studies were assessed with a total of 1618 cases and 1155 healthy controls. When results from all eligible studies were pooled into the meta-analysis, we found significant association between the IL-18 gene -607 C/A polymorphismand gastrointestinal cancer risk (CC vs AA: OR = 0.93, 95%CI = 0.72- 1.20; CC vs CA: OR = 0.76, 95%CI = 0.62-0.92; dominant model: OR = 1.25, 95%CI = 1.03-1.50; recessive model: OR = 1.09, 95%CI = 0.87-1.37). In the subgroup analysis, significant associations between the -607 C/A polymorphism and gastrointestinal cancer risk were found in esophageal cancer. However, this polymorphism did not appear to have any influence on gastric cancer and colorectal cancer susceptibility. In conclusion, this meta-analysis suggests that the -607 C/A polymorphism in the IL-18 gene may be associated with susceptibility to esophageal cancer. Further studies with large sample sizes are needed to confirm these conclusions.