IL-18 serum level and IL-18 promoter gene polymorphism in Iranian patients with gastrointestinal cancers

J Gastroenterol Hepatol. 2009 Jun;24(6):1119-22. doi: 10.1111/j.1440-1746.2009.05791.x.


Background and aim: Interleukin (IL)-18 level and association of its two promoter gene polymorphisms at -607 C/A and -137 G/C positions were investigated in Iranian patients with gastrointestinal (GI) cancers.

Methods: 232 cases of GI cancers and 312 healthy controls were enrolled. Serum level of IL-18 was measured by enzyme linked immunosorbent assay (ELISA) and genotyping of IL-18 gene polymorphisms were assessed by allele-specific polymerase chain reaction (PCR).

Results: There was a significant difference in the frequency of -137 G/C genotype between patients with stomach or colorectal cancers and control group. In patients with colorectal cancer, the frequency of the -607 AA/-137 GC genotype combination in unwell-differentiated cases was more than those with well-differentiated cancer. Haplotype analysis showed that in patients with stomach cancer -607 C/-137 C and -607 A/-137 G and in patients with colorectal cancer -607 C/-137 C were decreased compared with control group, and this difference reached statistical significance. Serum analysis revealed that the mean IL-18 serum level in stomach and colorectal cancer before and after surgical operation was significantly higher than healthy volunteers. Postoperative IL-18 level for all patients with colorectal cancer was significantly decreased compared with the levels before surgery.

Conclusion: Results of this investigation suggests that Single Nucleotide Polymorphism (SNP) at position -137 G/C and haplotype frequency may play a role in predisposition of Iranian patients to stomach and colorectal cancers. In addition, increasing serum IL-18 level may have clinical importance as a diagnostic marker in patients with stomach and colorectal cancer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles
  • Biomarkers / blood
  • Case-Control Studies
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Gastrointestinal Neoplasms / blood*
  • Gastrointestinal Neoplasms / genetics*
  • Genetic Predisposition to Disease
  • Genotype
  • Haplotypes
  • Humans
  • Interleukin-18 / blood*
  • Interleukin-18 / genetics*
  • Iran
  • Male
  • Middle Aged
  • Polymerase Chain Reaction
  • Polymorphism, Single Nucleotide*
  • Promoter Regions, Genetic


  • Biomarkers
  • Interleukin-18