Interleukin-8 -251 A/T gene polymorphism and gastric cancer susceptibility: a meta-analysis of epidemiological studies.

Previous studies suggested the relationship between interleukin (IL)-8 -251 A/T gene polymorphism and risk of gastric cancer (GC). However, the currently available results were not consistent. The present study aimed to quantitatively analyse this association using a meta-analysis. Published literature from PubMed, EMBASE and CNKI (China Knowledge Resource Integrated Database) were retrieved. Twelve case-control studies with 3012 cases of GC and 3893 controls were included. Overall, IL-8 -251 A/T polymorphism was not associated with the risk of GC. However, when stratified for ethnicity/country, the results showed that A allele carriers had an increased risk of GC while T allele carriers had a decreased risk of GC in Korean people. When stratified for Helicobacter pylori infection, the results showed that A allele carriers with H. pylori infection had an increased risk of GC while T allele carriers with or without H. pylori infection had a decreased risk of GC. When stratified for tumor location and histological type (Lauren's classification), A allele carriers had an increased risk of intestinal- and diffuse-type of GC and non-cardia cancer, while T allele carriers had a decreased risk of intestinal- and diffuse-type of GC and non-cardia cancer. These results suggest that overall IL-8 -251 A/T gene polymorphism is not associated with the risk of GC and the association may be varied according to histological type, tumor location, H. pylori infection and ethnicity/country. More well-designed studies based on larger population are needed to confirm our results and further evaluate the association between IL-8 -251 A/T gene polymorphism and gastric cancer.