High Serum Levels of Interleukin-18 Are Associated With Worse Outcomes in Patients With Breast Cancer

BACKGROUND/AIM: Interleukin (IL)-18, which belongs to the IL-1 superfamily of cytokines, is a known interferon-gamma (IFN-γ)-inducing factor. Since IFN-γ plays an essential role in anticancer immunity mediated through cytotoxic T cells, IL-18 may also contribute to the function of immunosurveillance. The aim of the study was to examine the association of IL-18 with the outcomes of patients with breast cancer. PATIENTS AND METHODS: Serum IL-18 levels were determined at baseline in 270 patients operated for breast cancer, and the relapse-free survival (RFS) was compared between IL-18-high and -low groups. The relationships between IL-18 and tumor-infiltrating lymphocytes (TILs) or the neutrophil-to-lymphocyte ratio (NLR) were also investigated. RESULTS: The RFS of patients was significantly better in the IL-18-low group than in the IL-18-high group (p=0.032). According to the multivariate analysis, IL-18 was a significant and independent predictive factor for RFS (hazard ratio(HR)=0.336; 95% confidence interval(CI)=0.147-0.727; p=0.0053). No association was observed between the IL-18 levels and TILs or NLRs. CONCLUSION: IL-18 levels may be useful for predicting the prognosis of patients who have received surgical treatment for breast cancer.