Markers of a metastatic niche in the omentum in ovarian cancer.

e18081 Background: Ovarian cancer spreads intraperitoneally due to the interaction of tumor cells and the omental mesothelium, creating a metastatic niche and supporting elements of cancer cell expansion such as adhesion, proliferation, migration, and neoangiogenesis. The purpose of the study was to analyze levels of VEGFA, IGF-I, IGF-II and TGFβ1 in omental tissues in ovarian cancer (OC). Methods: The main group included 23 patients with metastatic OC T3-4аN0-3M1; the comparison group – 21 patients with non-metastatic OC T3-4аN0-3M0; the control group – 19 non-cancer patients. Levels of VEGFA, IGF-I, IGF-II and TGFβ1 were measured by standard ELISA methods in tissues of primary tumors and the omentum. Results: Levels of growth factors in the comparison group were not elevated compared to control values. Growth factors in omental tissues in the main group were increased compared to control values: VEGFA – by 2.5 times, IGF-I – by 3.4 times, IGF-II – by 2.5 times, TGFβ1 - by 3.1 times. In the comparison group, the levels in omental tissues were lower than in the main group: VEGFA – by 1.7 times (p < 0.05), IGF-I – by 2.1 times, IGF-II – by 1.6 times (p < 0.05); TGFβ1 did not differ from the levels in the main group. Conclusions: Higher expression of VEGFА in the omentum with metastases can be considered a significant factor in the formation of signaling pathways between metastatic tumor cells and local non-cancer cells. IGF-I and IGF-II trigger the endothelial growth factor. The TGFβ1 activation in the omentum in metastatic ovarian cancer is necessary for the paracrine induction and transition of disseminated tumor and/or stem cells from the "sleeping" to the active state.