5556 Background: Antiangiogenic treatment in addition to platinum/taxane based chemotherapy was shown to improve progression-free survival in first- and second-line chemotherapy in ovarian cancer patients. Predictive markers for antiangiogenic treatment are of high interest. Therefore we investigated VEGF-receptor (VEGFR) expression as possible biomarker candidate in primary ovarian cancer tissue and its clinical impact. Methods: A total of 82 patients with primary ovarian cancer were enrolled into this study. Primary tumor tissue was analyzed for the expression of VEGFR1, VEGFR2 and VEGFR3 by immunhistochemistry. Moreover, the presence of circulating tumor cells (CTC) in the blood was detected by immunomagnetic enrichment and multiplex reverse transcriptase-polymerase chain reaction (Adnatest Ovarian Cancer, Adnagen). Disseminated tumor cells (DTC) in the BM were identified by immunocytochemistry using the pancytokeratin antibodyA45B/B3 and subsequent automatic detection based on staining and cytomorphology. Results: Positivity for at least one VEGFR was observed in 43% of cases. The positivity rates for VEGFR1, -2 and -3 were 34%, 17% and 27%, respectively. VEGFR-status of the primary tumor neither correlated with established clinicopathogical parameters (age, FIGO-stage, nodal status, grading, histological subtype) nor with the presence of CTC or DTC. In addition, VEGFR-status does not provide prognostic significance in regard to progression-free and overall survival (OS). Nevertheless, a trend was observed that patients, being positive for VEGFR3 at primary diagnosis, were more likely to experience suboptimal debulking (p = 0.074). CTC-positivity after adjuvant therapy significantly correlated with OS, but multivariable analysis showed only residual tumor as prognostic factor for OS. Conclusions: The VEGFR-family, albeit frequently expressed in our patient cohort, provided neither prognostic nor predictive relevance, but could probably be a predictor for debulking efficiency. The implementation of VEGFR-status into future biomarker studies should carefully be considered.