Interferon-gamma in Ascites Could Be a Predictive Biomarker of Outcome in Ovarian Carcinoma

Objective: The ovarian cancer-associated ascites is an ideal material for evaluating the interaction between the host immune system and cancer cells in the tumor micro-environment. The aim of this study was to investigate whether the selected target cytokine expression levels in ascites could serve as an immune biomarker for predicting outcomes in ovarian cancer.

Methods: Eighty-eight specimens of ovarian cancer-associated ascites were evaluated to select the target cytokine by a cytokine profiling kit. The 144 total samples were subsequently analyzed for this target cytokine. The correlation between the target cytokine and clinical characteristics was analyzed.

Results: Interferon-gamma (IFN-γ) was identified as the target cytokine. Higher levels of IFN-γ in the ascites of the tumor micro-environment were associated with advanced disease (p=0.012), higher tumor histological grading (p=0.004), and sub-optimal surgical status (p=0.040). By multivariate analysis, the adjusted hazard ratios (HRs) were 2.74 (95% confidence interval (CI) 1.85-4.05, p<0.001) for disease-free survival (DFS) and 1.72 (95% CI 1.01-2.93, p=0.048) for overall survival (OS) for a 10-fold increase in IFN-γ concentration in the ascites. An inverse dose-response relationship between IFN-γ level and survival was also noted (Ptrend<0.001 for DFS and Ptrend<0.042 for OS).

Conclusions: Patients with ovarian cancer and higher IFN-γ expression levels in cancer-associated ascites will have shorter DFS and OS. IFN-γ levels in the ascites may be a prognostic marker and a potential reference for immunotherapy targeting IFN-γ.