The involvement of genetic polymorphism of IL-10 promoter in non-small cell lung cancer.

Interleukin-10 (IL-10) is mainly an anti-inflammatory cytokine produced by a number of cells including normal and neoplastic cells and has been implicated in autoimmunity, transplantation tolerance and tumorigenesis. Inter-individual variations in IL-10 production were genetically contributed to polymorphisms within IL-10 promoter region. The aim of this study was to determine whether polymorphisms in the IL-10 gene promoter were involved in predisposing an individual to non-small cell lung cancer (NSCLC). A total of 154 patients with non-small cell lung cancer were recruited into this study, together with 205 age- and gender-matched healthy smokers acting as control subjects. Polymorphisms of sites within the promoter region of IL-10 gene were analyzed using polymerase chain reaction-restriction fragment length polymorphism technique on genomic DNA isolated from peripheral lymphocytes. The validity of this technique was proven by direct sequencing of polymerase chain reaction products. Statistical analyses were conducted to explore the contribution of polymorphism of IL-10 promoter to the susceptibility to NSCLC. The distribution frequencies of genotypes of IL-10-1082, -819 and -592 were significantly different between NSCLC patients and controls. Pearson chi2 analysis showed that the frequency for IL-10-1082 G allele, IL-10-819C allele and IL-10-592C allele was independently higher in NSCLC patient group than that in the control group. Higher odds ratios (ORs) for NSCLC were seen for individuals with G allele of IL-10-1082 [OR=5.26, 95% CI 2.65-10.4, p<0.0001], C allele of IL-10-819 [OR=1.57, 95% CI 1.15-2.16, p=0.005], C allele of IL-10-592 [OR=1.59, 95% CI 1.15-2.19, p=0.005]. The polymorphisms of IL-10 genes were significantly associated with the occurrence of NSCLC.