Clinical study of IL-18 and NANOG gene polymorphisms in prostate cancer patients*

Abstract Objective Recent studies have shown abnormal expression of NANOG and IL-18 to be related to cancer. However, the molecular mechanism by which IL-18 and NANOG gene polymorphisms are associated with prostate cancer is unclear. In this study, we examined whether IL-18 and NANOG gene polymorphisms and their interaction with prostate cancer-related risk factor are associated with the susceptibility to and clinicopathological development of prostate cancer among Chinese men. Methods Polymorphisms in the NANOG and IL-18 genes were evaluated for susceptibility in 120 patients with prostate cancer. The control group consisted of 125 samples from Chinese men. Genotyping was conducted using TaqMan allelic discrimination assays. Statistical analysis was performed using SPSS software. Results No association of NANOG and IL-18 gene polymorphisms and overall prostate cancer susceptibility was detected. The IL-18-607 CC genotype was significantly associated with a higher tumor grade ( P = 0.025) and stage ( P =0.001). The IL-18-137 GG genotype correlated with a higher tumor grade ( P = 0.028) and stage ( P = 0.008). The IL-18-137G allele was significantly more frequent in patients with lymph node metastasis ( P = 0.035). The IL-18-607 CC genotype was associated with distant metastasis ( P = 0.025). However, no significant association was observed between NANOG polymorphisms and any clinicopathological feature. The Cox proportional hazard model showed that tumor grade and stage grouping were independent prognostic factors in IL-18, while IL-18 polymorphism was not. Polymorphism variants in the IL-18 (IL-18-607 and IL-18-137) and NANOG (genotypes AC) genes might be associated with a worse prognosis of patients with prostate cancer. Conclusion NANOG may be associated with the early stages of prostate cancer carcinogenesis. IL-18 and NANOG gene polymorphisms may play a major role in the growth, invasion, and metastasis of prostate cancer.