Objective
The aim of this study was to determine whether the presence of IL-18 polymorphisms -137 G/C and -607 A/C was associated with grade, clinical stage, and survival in patients with prostate cancer.
Methods
The study cohort included 126 patients with prostate cancer. Control group consisted of 125 samples from Chinese population. Genomic DNA was extracted from EDTA-anticoagulated peripheral blood leukocytes by the salting-out method. The genotyping of the two IL-18 polymorphisms was performed using predesigned TaqMan SNP Genotyping Assays.
Results
The studied IL-18 gene polymorphisms did not influence susceptibility to prostate cancer in the analyzed group of patients (IL-18-607, P = 0.342; IL-18-137 P = 0.715) but may contribute to disease onset and aggressiveness. IL-18-607 CC genotype was significantly associated with higher tumor grade (P = 0.025) and stage (P = 0.001). IL-18-137 GG genotype was correlated with higher tumor grade (P = 0.018) and stage (P = 0.007). The Cox proportional hazard model showed that tuumor grade and stage grouping were independent prognostic factors but IL-18 polymorphism was not. Polymorphism variants in the IL-18 gene (IL-18-607 and IL-18-137) may be associated with a worse prognosis for prostate cancer.
Conclusion
High levels of IL-18 production may play a major role in the growth, invasion and metastasis of prostate cancer.