Stratification Analysis and Case-control Study of Relationships between Interleukin-6 Gene Polymorphisms and Cervical Cancer Risk in a Chinese Population

Interleukin-6 (IL-6), a central proinflammatory cytokine, maintains immune homeostasis and also plays important roles in cervical cancer. Therefore, we aimed to evaluate any associations of IL-6 gene polymorphisms at positions -174 and -572 with predisposition to cervical cancer in a Chinese population. The present hospitalbased case-control study comprised 518 patients with cervical cancer and 518 healthy controls. Polymorphisms of the IL-6 gene were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Patients with cervical cancer had a significantly higher frequency of the IL-6 -174 CC genotype [odds ratio (OR) =1.52, 95% confidence interval (CI) = 1.06-2.19; p=0.02], IL-6 -572 CC genotype (OR =1.91, 95% CI = 1.16-3.13; p=0.01) and IL-6 -174 C allele (OR =1.21, 95% CI = 1.02-1.44; p=0.03) compared to healthycontrols. When stratifying by the FIGO stage, patients with III-IV cervical cancer had a significantly higher frequency of IL-6 -174 CC genotype (OR =1.64, 95% CI =1.04-2.61; p=0.04). The CC genotypes of the IL-6 gene polymorphisms at positions -174 and -572 may confer a high risk of cervical cancer. Additional studies with detailed human papillomavirus (HPV) infection data are warranted to validate our findings.