Ascites and Serum Interleukin-10 Levels as a Prognostic Tool for Ovarian Cancer Outcomes

Interleukin-10 (IL-10) has been shown to be present at high levels in the ascites of ovarian cancer (OC) patients; however, little is known about its prognostic value. We sought to correlate IL-10 levels in ascites and sera of OC patients with clinicopathologic characteristics and oncologic outcomes. IL-10 levels and clinical data from biobanked ascites and serum samples of OC patients were evaluated. Receiver operating characteristic curves were used to quantify marker performance and identify IL-10-high and IL-10-low groups. Correlations between IL-10 levels and clinicopathologic data were performed. Survival outcomes were calculated, while the factors affecting them were also investigated. A total of 106 patients had ascites samples, of which 44 serum samples were also available. Mean ascites IL-10 levels were significantly higher in patients with serous histology compared to endometrioid histology (p = 0.024). Fold-change in ascites IL-10 during treatment positively correlated with clinical response, as determined by a change in serum cancer antigen (CA)-125 levels (p = 0.0126). Median progression-free survival (PFS) and overall survival (OS) were shorter in patients with high compared with low ascites IL-10 levels (PFS: 18 versus 60 months; p = 0.007, OS: 42 versus 85 months; p = 0.029). A significant positive correlation was seen between ascites and sera IL-10 levels (p = 0.019). In multivariable analyses, a high ascites IL-10 level was associated with a significantly worse prognosis (PFS hazard ratio (HR) = 1.93; p = 0.02). Patients with high ascites levels of IL-10 have worse outcomes, which are likely reflective of the immunosuppressive effect of IL-10. This highlights its potential role as an immunomodulator in the tumor microenvironment, leading to OC immune evasion.