[Association of genetic polymorphisms in IL-6 and IL-1β gene with risk of lung cancer in female non-smokers].

BACKGROUND

Interleukin-6 (IL-6) and interleukin-1β (IL-1β), known as multifunctional cytokines with high biological activity, play an important role in physiological and pathological responses such as inflammation, immune response and even tumors. There have been multiple polymorphism loci found in IL-6 gene and IL-1β gene. The aim of this study is to investigate the relationship between IL-6-643 (C/G) and IL-1β-31 (C/T) polymorphisms and lung cancer risk among female non-smokers and explore the interaction effects on lung cancer risk between this two polymorphisms and potential risk factors such as cooking oil fumes exposure and history of tuberculosis.

METHODS

We performed a case-control study using 363 female lung cancer patients as cases and 370 healthy volunteers as controls. Genomic DNA was extracted from peripheral blood samples using classical phenol chloroform method. The genotyping of IL-6-634 or IL-1β-31 polymorphisms was performed using Taqman real time PCR technique by ABI7500. Two sided χ2 test was used to compare the distribution of the genotypes and risk factors between cases and controls. Unconditional Logistic regression analysis was performed to calculate the odds ratios (ORs) with 95% confidence intervals (CIs) for estimating the association between certain genotypes and lung cancer and exploring the interaction of risk factors and genetic polymorphisms.

RESULTS

The risk of lung cancer was significantly higher in those with IL-6-634 CG genotype than those with CC genotype (OR=1.61, 95%CI: 1.19-2.19, P=0.002). The CG or GG genotype carriers had an elevated risk of lung cancer than CC genotype carriers (OR=1.48, 95%CI: 1.10-1.98, P=0.01). No significant association was observed between IL-1β-31 gene polymorphism and lung cancer risk. Compared with IL-6-634 CC genotype carriers with no cooking oil fumes exposure, a significant higher risk was found in individuals who were CG or GG genotype carriers with exposure to cooking oil fumes (OR=2.45, 95%CI: 1.54-3.90). Compared with IL-6-634 CC genotype carriers with no history of tuberculosis, a significant elevated risk was found in individuals who were CG or GG genotype carriers with history of tuberculosis (OR=2.44, 95%CI: 1.05-5.66).

CONCLUSIONS

Our results indicated that IL-6-634 polymorphism was associated with the risk of lung cancer risk in female non-smokers. Individuals with both IL-6-634 CG or GG genotype and exposure to cooking oil fumes had a higher risk of lung cancer. Also individuals with both IL-6-634 CG or GG genotype and history of tuberculosis had an elevated risk of lung cancer.