• Interleukin-6 gene polymorphisms and gastric cancer: A Systematic Review and Meta-Analysis
  • Mahdieh SobhZahedi,1,* Mohammad Hossein YektaKooshali,2
    1. M.Sc. in Molecular Genetics, Department of Biology, Faculty of Science, University of Guilan, Rasht, Iran.
    2. M.Sc. in Cellular and Molecular Biology, Razi Hospital, School of nursing, Midwifery and Paramedicine, Guilan University of Medical Sciences, Rasht, Iran.


  • Introduction: Gastric cancer is the fifth leading cancer which common both in men and women in developing countries. Less than 5% of stomach cancers occur in people under 40 years of age, with 81.1% of that 5% in the age-group of 30 to 39 and 18.9% in the age-group of 20 to 29. Cancer is a multi-factorial progressive illness which advanced under the impact of genes. Interleukin-6 (IL-6) is a pleiotropic, pro-inflammatory cytokine involved in many biological processes, including cancer and autoimmune diseases. Different types of cancers were influenced by the three SNPs (rs1800795, rs1800796 and rs1800797) of the IL-6 gene. This study aimed to investigating Interleukin-6 gene polymorphisms and risk of gastric cancer as a Systematic Review and Meta-Analysis.
  • Methods: This study was performed based on the PRISMA guideline. Documents gathered by searching through the Web of Sciences, Scopus, PubMed/Medline, OVID, and COCHRANE databases which published before 0101/2022 that related to interleukin-6 gene polymorphisms and risk of gastric cancer. Articles were searched using standard keywords as well as Mesh and Mesh Entry and all probabilistic combinations of words using Boolean operators. Data searching, extracting and quality appraising were done by two researchers, independently. At last, Random-effects size based on Cochrane test and I2 were used. Data analysis was performed using the Comprehensive Meta-Analysis Ver.2, and the significance level of the test was considered less than 0.05.
  • Results: Based on the meta-analysis conducted in 14 included studies, the total sample size of patients with 7788. The IL-6 -572G/C polymorphism had significant relationship with the increasing risk of stomach cancer under four genetic models [C vs. G: OR = 1.16, [95%CI: 1.03–1.30], p-value = 0.0069; CC vs. GG: OR = 1.41, [95%CI: 1.10–1.81], p-value = 0.0076; CC vs. CG + GG: OR = 1.29, [95%CI: 1.07–1.55], p-value = 0.0080; CC + CG vs. GG: OR = 1.41, [95%CI: 1.09–0.81], p-value = 0.0088]. The IL-6 -596G/A polymorphism had no relationship with the increasing risk of stomach cancer under four genetic models [AA vs. GG: OR = 1.71, [95%CI: 0.54-5.34], p-value = 0.3551; AA vs. AG+GG: OR = 1.83, [95%CI: 0.6-5.37], p-value = 0.2846; AA+AG vs. GG: OR = 0.98, [95%CI: 0.54-1.76], p-value = 0.9657; AG vs. AA=GG: OR = 1.21, [95%CI: 0.67–2.2], p-value = 0.530]. As the same, the IL-6 -174G/C polymorphism had no significant relationship with the increasing risk of stomach cancer under four genetic models [C vs. G: OR = 1.12, [95%CI: 0.85-1.5], p-value = 0.4087; CC vs. GG+GG: OR = 1.07, [95%CI: 0.81-1.40], p-value = 0.6450; CC+CG vs. GG: OR = 1.08, [95%CI: 0.92-1.22], p-value = 0.4317; CG vs. CC+GG: OR = 1.041, [95%CI: 0.9–1.19], p-value = 0.6024].
  • Conclusion: Results from this study, more confidently showed that the IL-6 gene SNPs (rs1800795, rs1800796 and rs1800797) in humans are related with increased cancer risks. Therefore, these three polymorphisms of the IL-6 gene have the potential to be evaluated as a population based rapid, low-cost PCR prognostic biomarkers for different types of cancers diagnosis and research.
  • Keywords: Interleukin-6; Gene polymorphisms; Gastric Cancer