e18090 Background: The standard therapy of patients with ovarian cancer consists of primary surgery followed by chemotherapy. Initial response rates are very high, but recurrence occurs in 85% of the cases. Personalized ex vivo analyses of various anti-tumor compounds in a standardized tissue slice culture system (1) might be a very promising approach for individualized therapeutic decisions. In comparison to cell culture, tumor slice cultures maintain the direct tumor microenvironment which plays a role in resistance mechanisms and thus therapy response. Methods: Patient derived tumor cultures (1) are grown under standardized conditions and are analyzed semi-automated. Patient’s tumor samples were collected during surgery, cut into standardized slices and were cultivated in triplicates for 2, 4, 7 and 14 days and treated with standard therapy for 7 days. A baseline control was prepared at day 0. The cultured tissue is PFA-fixated and paraffin embedded. Hematoxylin eosin staining was performed for microscopic evaluation of morphologic structures. Subsequently, immunohistochemical staining against CD3 was applied to examine the immune setting of the tumor and its environment. Results: Ovarian tumor tissues remained their morphological properties over a period of 14 days. Parameters like cellular formation, proliferation and heterogeneity were adequately represented in the cultures.. Staining against CD3 revealed T-cells in ovarian tumor tissue slices up to 14 days ex vivo and individual response to treatment was observable. Conclusions: Correlation to clinical data is ongoing to analyze the tissue culture model of ovarian cancer for clinical usage. Different approaches, concerning mutational burden, immunological signature and histology are considered for decision of response and non-response.