Association between Interleukin-8-251A/T polymorphism and gastric cancer susceptibility: a meta-analysis based on 5286 cases and 8000 controls

Objectives: Published data on the association between Interleukin-8-251A/T polymorphism and gastric cancer (GC) risk are inconclusive. Thus, we conducted a meta-analysis to evaluate the relationship between cyclin D1 G870A polymorphism and GC risk. Methods: We searched PubMed, EMBASE, Web of science and the Cochrane Library up to July 12, 2015 for relevant studies. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to estimate the strength of associations. Results: Twenty-six studies published from 2004 to 2015, with a total of 5286 cases and 8000 controls, were included in this meta-analysis. The pooled results showed that there was significant association between Interleukin-8-251A/T polymorphism and GC risk in any genetic model. In the subgroup analysis by ethnicity, the effects remained in Asians. However, no genetic models reached statistical association in Europeans. The subgroup analysis stratified by Source of controls showed an increased breast cancer risk in hospital-based (HB) studies in any genetic model except recessive model. However, there was no association in any genetic model in population based (PB) studies. When stratifying by Genotyping method, we found statistical association in Non-RFLP (restriction fragment length polymorphism) in any genetic model except heterozygote comparison, the effect was remain in PCR-RFLP in dominant model and heterozygote comparison. Conclusions: This meta-analysis suggests that Interleukin-8-251A/T polymorphism is a risk factor for susceptibility to GC in overall population, especially in Asians, in hospital populations and in Non-RFLP. While, there was no association in Europeans and in general population. Further large scale multicenter epidemiological studies are warranted to confirm this finding.