Current evidence suggests that chronic inflammation is associated with tumor development and progression. Interleukin-18 (IL-18) plays a central role in inflammation and the immune response, contributing to the pathogenesis and pathophysiology of infectious and inflammatory diseases. The objective of this study was to determine whether the presence of IL-18 polymorphisms -137 G/C (rs187238) and -607 A/C (rs1946518) was associated with size, grade, TNM stage, and survival in patients with renal cell carcinoma (RCC). The study cohort included 158 patients with RCC. Control group consisted of 506 samples from Spanish population. The studied IL-18 gene polymorphisms did not influence susceptibility to RCC in the analyzed group of patients (IL-18-607, p = 0.318; IL-18-137 p = 0.740) but may contribute to disease onset and aggressiveness. IL-18-607 CC genotype was significantly associated with higher tumor size (p = 0.001), grade (p = 0.030), T (p = 0.001), M (p = 0.012), and stage (p = 0.002). IL-18-103 GG genotype was correlated with higher tumor size (p = 0.036), grade (p = 0.017), T (p = 0.026), and stage (p = 0.011). The Cox proportional hazard model showed that nuclear 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 RCC. High levels of IL-18 production may play a major role in the growth, invasion and metastasis of renal cancer.
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