Abstract A086: Omental fat in ovarian cancer induces lymphangiogenesis

Ovarian cancer metastasis occurs by direct multifocal seeding into the peritoneum as well as by migration through the lymphatic system. High-grade ovarian carcinoma patients often present with distant metastases. Significant risk factors for the development of those are stage, grade, and lymph node involvement. The increase of the number of lymphatic vessels seems to be implicated in ovarian tumor progression. While the tropism of ovarian cancer cells for fat is well described, the potential impact of an adipose-rich microenvironment on the dissemination of metastasis via lymphatic vessels has never been investigated. So far, in this study, we examined the effect of omental fat on lymphangiogenesis in ovarian carcinoma. For that we used a cohort of 80 ovarian cancer specimens. We observed a higher number of tumor-associated vessels and principally lymphatic vessels in ovarian cancer in contact with the omentum. These lymphatic vessels are predominantly localized along the fat tissue. A higher secretion of VEGF-C is observed in ovarian tissues containing fat compared to the ones without fat, giving a potential explanation to the observed increase of lymphatic vessels in fatty tissues. We also developed a healthy fat tissue explant culture model and treated whole tissue explants with ascites. Herein, we saw an increase of the number of adipose-derived stem cells (ADSCs). These ADSCs express lymphatic markers such as D2-40 and Lyve-1. We also observed an impact of fat supernatant on the proliferation, migration and tube formation of lymphatic endothelial cells in vitro. In conclusion, we can say that omental fat in ovarian cancer seems to have an impact on lymphangiogenesis. The close contact of ascites with fat tissue seems to lead to a differentiation of adipose-derived stem cells into lymphatic endothelial cells. Further investigations must be performed to understand the exact mechanisms underlying this phenomenon. Citation Format: Benedicte M.A. Lenoir, Dyke Ferber, Victor Starrach, Meggy Suarez-Carmona, Sarah Schott, Inka Zoernig, Dirk Jager, Niels Halama. Omental fat in ovarian cancer induces lymphangiogenesis [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A086.