Interleukin-18 gene promoter and serum level in women with ovarian cancer

IL-18, initially defined as a potent inducer of IFN- gamma production, is a systemic, multifunctional cytokine with both pro-cancerous and anti-cancer activities. The contribution of the IL-18 promoter polymorphisms at positions -607 (C/A) and -137 (G/C) to cancer development has been reported. We sought to examine IL-18 serum level and its polymorphisms in Iranian women with ovarian cancer. Single nucleotide polymorphisms (SNPs) at positions -607 (C/A) and -137 (G/C) were analyzed by allele-specific polymerase chain reaction in 85 women with ovarian cancer and 158 healthy controls. IL-18 serum level was determined using ELISA method. No significant association was found between the allele, genotype, and haplotype distributions of the SNPs and ovarian cancer. Mean IL-18 serum level was significantly higher in patients than in controls (P = 0.008). Comparing IL-18 serum levels with genotypes at positions -607 and -137 revealed no significant difference. No association was also found between IL-18 levels and the disease stage. In conclusion, our results indicate that IL-18 promoter polymorphisms at positions -607 (C/A) and -137 (G/C) appear not to confer susceptibility to ovarian cancer in Iranian population; however, IL-18 serum level increases in ovarian cancer patients.