Interleukin-1B and interleukin-1 RN polymorphisms and gastric carcinoma risk: A meta-analysis

Background and Aim: We aimed to explore the role of interleukin (IL)-1B cluster gene polymorphisms at positions -511, -31, and +3954 and the receptor IL-1RN variable number tandem repeat polymorphisms in the susceptibility to gastric carcinoma through a systematic review and meta-analysis. Methods: Each initially included article was scored for quality appraisal. The desirable data were extracted and registered into databases. Studies that deviated from Hardy-Weinberg equilibrium were excluded. Eighteen studies were ultimately eligible for the meta-analysis of IL1B-511, 21 studies for IL1B-31, 10 studies for IL1B+3954, and 20 studies for IL1RN variable number tandem repeat genetic polymorphisms, respectively. Original groups were collapsed and re-grouping was adopted in line with the most probably appropriate genetic models. Potential sources of heterogeneity were sought out via stratification and sensitivity analyses, and biases across studies were estimated. Results: The pooled odds ratios (95% confidence intervals, P-value) associated with IL-1B -511 T carriers versus CC genotypes and with RN *2 carriers versus L/L were 1.23 (1.04-1.45, P = 0.015) and 1.26 (1.06-1.51, P = 0.010), respectively, for overall gastric carcinoma; 1.31 (1.04-1.64, P = 0.020) and 1.47 (1.21-1.79, P = 0.000), respectively, for non-cardia gastric cancer; 1.55 (1.05-2.28, P = 0.026) and 1.66 (1.23-2.25, P = 0.001), respectively, for intestinal type gastric carcinoma; and 1.33 (1.04-1.71, P = 0.023) and 1.31 (1.07-1.61, P = 0.010), respectively, in Caucasians for overall gastric carcinoma. The pooled odds ratio (95% confidence interval, P-value) regarding IL-1B-31 CC plus TT versus CT was 0.73 (0.60-0.89, P = 0.002) for intestinal type gastric carcinoma. Genotyping methods and publication time could constitute the sources of heterogeneity across studies. Publication biases were not found. Conclusion: IL-1B -511 T allele and IL-1 RN *2 VNTR are significantly associated with an increased risk of developing gastric carcinoma and even more significantly with non-cardia gastric carcinoma or with intestinal-type gastric carcinoma. Both are significantly associated with an increased risk of developing gastric carcinoma among Caucasians, but not among Asians or Hispanics.