Abstract 1434: Levels of IL-12 family cytokines in ascitic fluid are associated with extent and resectability of ovarian cancer and correlate with overall survival.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC Background: Ovarian cancer (OC) is commonly associated with ascites and predominantly remains in the peritoneal cavity. Soluble factors present in ascites such as growth factors and cytokines likely play a key role in local tumor behavior including stage, invasiveness and resectability and survival. Members of IL-12 family (IL-12p70, IL-23, IL-27 and IL-35) play a critical role in the regulation of inflammatory response. However, their role as local factors in ovarian cancer growth has not been well studied. We hypothesized that that the level of these important immunomodulatory and pro-inflammatory cytokines are associated with the clinical behavior of OC. Methods: Ascites fluid was collected and analyzed from women undergoing maximal debulking surgery for presumed OC, and relevant clinical endpoints were abstracted. Concentrations of IL-12 related cytokines (IL-23, IL-27, IL-35, and IL-12p70) were assessed by ELISA. Cytokines were also assessed on matching pre-surgery plasma samples. Cytokine concentrations between matched ascites and plasma samples were examined using scatter plots and Spearman correlations. Associations between ascites concentrations and clinical characteristics were assessed using Wilcoxon rank-sum tests. Associations between ascites levels with overall survival in newly diagnosed invasive OC patients were assessed by Cox proportional hazards models using a log2 transformation. Results: Ascites fluid was analyzed from 20 patients with primary epithelial OC including 18 serous histology, 19 patients with stage III or IV disease: 16 (80%) were optimally debulked. We observed that higher levels of IL-12p70 were associated with locally invasive disease including higher rates of sub-optimal debulking (p=0.0074) and stage IV disease (p=0.012). For other IL-12 family members we observed similar associations between higher cytokine levels and suboptimal disease and stage IV disease including IL-23 (p=0.73, p=0.17), IL-27 (p=0.041, p=0.018), and IL35 (p=0.12, p=0.11), respectively. In addition, increase in IL-23 was associated with worse overall survival (log2 HR = 1.85, p=0.031). Conclusions: Higher levels of IL-12 family of cytokines in ascitic fluid are associated with several surrogates of biological aggressiveness in OC including stage, resectability and survival. Given the importance of local tumor environment on clinical behavior, a detailed understanding of IL-12 pathway may help in developing novel therapeutic strategies to treat OC. Citation Format: Eati Basal, Mathew S. Block, Matthew J. Maurer, Krista Goergen, Courtney L. Erskine, Marshall Behrens, Kimberly R. Kalli, Keith Knutson, William Cliby. Levels of IL-12 family cytokines in ascitic fluid are associated with extent and resectability of ovarian cancer and correlate with overall survival. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1434. doi:10.1158/1538-7445.AM2013-1434