Association of interleukin 1 beta (IL-1β) polymorphism with mRNA expression and risk of non small cell lung cancer

Interleukin 1 beta (IL- 1β), a key proinflammatory cytokine encoded by the interleukin 1 beta gene, has been associated with chronic inflammation and plays an important role in lung inflammatory diseases including lung cancer. Elevated levels of Interleukin 1proteins, in particular interleukin 1 beta greatly enhance the intensity of the inflammatory response.

To study the role of interleukin 1 beta-31C > T and -511 T > C polymorphism in the pathogenesis of non small cell lung cancer (NSCLC).

One hundred and ninety non small cell lung cancer patients and 200 healthy age, sex, smoking and dwelling matched controls were used for polymorphic analysis by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) followed by sequencing. Normal tissues of 48 histopathologically confirmed non small cell lung cancer patients were taken for mRNA expression analysis. Quantitation of interleukin 1 beta was carried out by quantitative real time PCR.

The T/T genotype of interleukin 1 beta-31 gene was significantly associated with increased risk of NSCLC [(P = 0.001, OR - 2.8 (95%CI 1.52-5.26)]. The interleukin 1 beta - 511 T > C does not show any difference between the NSCLC and control group (P = 0.3, OR - 0.72 (95%CI 0.41-1.28). Quantitative analysis of mRNA showed significant association with interleukin 1 beta T allele as compared to the interleukin 1 beta-31C allele (P = 0.006).

We conclude that lung cancer risk genotype interleukin 1 beta-31TT results in increased expression of interleukin 1 beta mRNA in lung cancer patients. Our data suggest that this genotype (IL1β -31TT) in the interleukin 1 beta regulatory region provide a microenvironment with elevated inflammatory stimuli and thus increasing the risk for lung cancer.