Systematic evaluation of vascular endothelial growth factor receptor expression in primary ovarian cancer and its clinical relevance

Objectives: The identification of novel molecular biomarkers, predicting outcome of ovarian cancer, is highly desirable. Considering that angiogenesis is a critical factor for ascites development and peritoneal dissemination in ovarian cancer and given that the vascular endothelial growth factor (VEGF) receptor signaling axis is a major driver of angiogenesis, we sought to analyze expression and compartmental distribution of VEGF-receptor family in ovarian cancer and to assess its clinical relevance with regard to established clinicopathological parameters, tumor cell dissemination to the bone marrow (BM) and the patient's survival.

Methods: A total of 73 patients with primary ovarian cancer were enrolled into this study. Primary tumor tissue was analyzed for the expression of VEGF-R1, VEGF-R2 and VEGF-R3 by immunhistochemistry. The presence of disseminated tumor cells (DTC) in the BM was analyzed by immunocytochemistry using the pancytokeratin antibody A45B/B3 and subsequent automatic detection based on staining and cytomorphology.

Results: In primary ovarian cancer tissue, VEGF-receptor expression, detected with an overall frequency of 44%, was mostly located in the vascular wall and across the stroma; positivity rates for VEGF-R1, VEGF-R2 and VEGF-R3 were 34%, 18% and 26%, respectively. Total VEGF-receptor expression correlated with residual tumor after primary debulking surgery and the presence of DTC at primary diagnosis (p = 0.035, p = 0.023, respectively). Interestingly, VEGF-R1 positivity significantly correlated with decreased progression-free survival (p = 0.026).

Conclusions: This is the first report, suggesting total VEGF-receptor status as a molecular biomarker for monitoring tumor cell spread to the BM and, particularly, revealing prognostic significance of VEGF-R1.