Background: Cytokines are intercellular hormones, believed to play a functional role in the natural history of various malignant diseases. In vitro and in vivo studies have indicated that interleukin 6 (IL-6) may provide autocrine and paracrine growth stimulation in ovarian cancer cells.
Methods: In the present study we measured IL-6 in the serum of 73 patients with FIGO stage I to IV ovarian cancer. Enzyme-linked immunosorbent assay (ELISA) was used to determine IL-6 serum levels. Results were correlated to clinical data. Serum levels of IL-6 were additionally evaluated in a panel of 50 normal controls.
Results: Median serum levels of IL-6 in patients with ovarian cancer and normal controls were 55.6 (minimum 0, maximum 2869.0) pg/ml and 0.5 (minimum 0, maximum 2.14) pg/ml, respectively (Mann-Whitney U test, P = 0.0001). When serum levels of IL-6, taken prior to therapy, were grouped by FIGO stage, lymph node involvement, and grading of tumor cells, we found a statistically significant correlation with FIGO stage (Mann-Whitney U test, P = 0.04). Lymph node involvement and grading of tumor cells were not correlated with IL-6 levels. Elevated IL-6 serum levels prior to therapy were significantly correlated with poorer disease-free (log-rank test, P = 0.003) and overall survival (log-rank test, P = 0.01).
Conclusion: Elevated IL-6 serum levels prior to therapy are correlated with a poor relapse-free and overall survival in ovarian cancer patients.