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

BACKGROUND: Chronic inflammation is associated with neoplasms and several types of cancer. Therefore, polymorphisms in the inflammation-related genes could modify the cancer susceptibility.

OBJECTIVE: 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.

METHODS: 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.

RESULTS: 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.

CONCLUSION: This study demonstrates an association between the carrier status of IL-1RN* 2 and CRC and GC in an Iranian population.