In the present study, associations between pretreatment interleukin 6 (IL-6), interleukin 8 (IL-8) and C-reactive protein (CRP) serum levels and epithelial ovarian cancer (EOC) were analyzed using commercially available, enzyme-linked immunosorbent assay (ELISA) in 118 patients and 64 control subjects. Values were correlated with clinicopathological characteristics and outcomes. Control variables included age, stage, grade, histological type and residual tumor size. Kaplan-Meier plots and univariate and multivariate Cox proportional hazards models were used to study the associations between IL-6, IL-8 and CRP levels, control variables, overall survival and disease-free survival. The median IL-6, IL-8 and CRP serum levels in EOC were significantly higher than in the normal control group; 11.5 pg/mL (range, 3.4-62.6) versus 2.9 (1.1-12.3) pg/mL (p<0.001) and 21.8 pg/mL (range, 16.4-105.3) versus 9.3 (4.3-32.4) pg/mL (p<0.001) and 9.51 mg/L (range, 0.3-129.2) versus 1.2 (0.1-11.5) mg/L (p = 0.001), respectively. High levels of IL-6, IL-8 and CRP were associated with reduced overall survival (P = 0.003, P = 0.035, P = 0.046) and disease-free survival (P<0.001, P = 0.026, P = 0.043), respectively. Multivariate analyses showed that IL-6, IL-8 and CRP serum levels independently predicted disease-free survival (P = 0.011, P = 0.001 and P = 0.021), and overall survival (P = 0.004, P = 0.014 and P = 0.016), respectively. EOC is associated with extensive changes in the serum cytokine environment, highlighting the importance of further investigations of relative cytokine level changes. Preoperative serum IL-6, IL-8, and CRP levels seem promising for distinguishing EOC patients from healthy controls; however, their clinical value is still to be confirmed. High levels of IL-6, IL-8, and CRP in EOC patients have been suggested to be a poor prognostic factor for OS and DFS.
Keywords: C-reactive protein (CRP); epithelial ovarian cancer (EOC); interleukin-6 (IL-6); interleukin-8 (IL-8); prognostic factors.