Association of interleukin-1 gene polymorphism with risk of gastric and colorectal cancers in an Iranian population

Chronic inflammation is associated with neoplasms and several types of cancer. Therefore, polymorphisms in the inflammation-related genes could modify the cancer susceptibility. To investigate the associations between IL-1RN VNTR and rs419598 polymorphisms in IL-1 receptor antagonist (IL-1ra) and colorectal cancer (CRC) and gastric cancer (GC) in an Iranian population. In this study, 126 cancer cases (91 CRC and 35 GC) and 97 healthy controls were included. Genotyping of IL-1RN VNTR and rs419598 was performed by PCR amplification and PCR-RFLP, respectively. Logistic regression was applied to identify the independent risk factors for colorectal and gastric cancers by computing the odds ratio (OR) and 95% confidence intervals (95% CI). All statistical analyses were performed using the SPSS statistical software. There were significant differences between cancer groups and control group concerning the frequency of A1/A2 genotypes in IL-1RN VNTR polymorphism. The carrier status of IL-1RN* 2 allele was associated with increased risk of CRC (p = 0.0003; OR = 0.02; 95% CI: 0.491-0.85) and GC (p = 0.0006; OR = 0.106; 95% CI: 0.321-0.035). Also, the homozygous ILRN *2/*2 genotype was associated with increased risk of gastric cancer (p = 0.04; OR = 0.133; 95% CI: 0.020-0.908). There was no association between different alleles of rs419598 and CRC and GC. This study demonstrates an association between the carrier status of IL-1RN* 2 and CRC and GC in an Iranian population.