Abstract 3476: Higher plasma levels of heparan sulfate are associated with improved survival of patients with advanced ovarian cancer.

Abstract

Abstract Background: Ovarian cancer (OC) is the leading cause of gynecologic cancer death in the United States. Survival in advanced OC is highly variable and is impacted by the endogenous anti-tumor immune response. Toll-like receptors (TLR) on tumor-infiltrating leukocytes can modulate anti-OC immunity. Heparan sulfate (HS) is an oligosaccharide component of the extracellular matrix that, when released, binds and triggers TLR-4 to induce production of multiple cytokines; HS is liberated from the extracellular matrix by heparanase, which is overexpressed by many ovarian cancers. We therefore explored the association between plasma levels of HS, heparanase, proinflammatory and immunosuppressive cytokines, and survival in patients with advanced OC. Methods: We designed a two stage cohort study of plasma biomarkers in ovarian cancer patients. For the pilot stage, we enrolled 100 patients with advanced OC (AJCC Stage III and IV), 50 patients with early stage OC (Stage I and II), and 50 patients with benign surgical conditions from the Mayo Ovarian SPORE Biospecimens Core. For the expansion stage, 257 patients with advanced OC were enrolled. Presurgical plasma samples were assayed for HS, heparanase, and multiple cytokines by ELISA and electrochemiluminescence. Differences in plasma levels between benign, early, and advanced OC patient groups were assessed using plate-adjusted linear models. Associations between plasma levels of HS and heparanase with overall survival in advanced OC patients were assessed by Cox proportional hazards models using a log2 transformation; total effects across stages were estimated using a meta-analysis approach. Results: In the pilot cohort, soluble HS levels were similar in control (mean +/ STD: 88.26 +/- 32.23), early stage (93.91 +/- 37.77), and advanced OC (93.55 +/- 40.44), with similar values observed in the expansion cohort (129.29 +/- 95.64). There was no correlation between heparanase and HS levels. Higher levels of HS were associated with improved overall survival (log2 HR = 0.62, p = 0.042; HR = 0.84, p = 0.014; HR = 0.82, 95% CI: 0.71-0.93, p = 0.003 for the pilot, expansion, and combined sets, respectively). There was no association between heparanase levels and overall survival (all p > 0.45). Conclusions: Neither soluble HS nor heparanase were elevated in presurgical OC patients relative to controls; however, higher levels of HS were associated with improved survival in patients with advanced OC. These results suggest that HS may play a key role in modulating the innate immune response to OC. Citation Format: Matthew S. Block, Matthew J. Maurer, Krista M. Goergen, Courtney L. Erskine, Marshall D. Behrens, Kimberly R. Kalli, Keith L. Knutson. Higher plasma levels of heparan sulfate are associated with improved survival of patients with advanced ovarian cancer. [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 3476. doi:10.1158/1538-7445.AM2013-3476