Ovarian Cancer represents the most fatal type of gynecological malignancies. A number of processes are involved in the pathogenesis of ovarian cancer, especially within the tumor microenvironment. Angiogenesis represents a hallmark phenomenon in cancer, and it is responsible for tumor spread and metastasis in ovarian cancer, among other tumor types, as it leads to new blood vessel formation. In recent years angiogenesis has been given considerable attention in order to identify targets for developing effective anti-tumor therapies. Growth factors have been identified to play key roles in driving angiogenesis and, thus, the formation of new blood vessels that assist in “feeding” cancer. Such molecules include the vascular endothelial growth factor (VEGF), the platelet derived growth factor (PDGF), the fibroblast growth factor (FGF), and the angiopoietin/Tie2 receptor complex. These proteins are key players in complex molecular pathways within the tumor cell and they have been in the spotlight of the development of anti-angiogenic molecules that may act as stand-alone therapeutics, or in concert with standard treatment regimes such as chemotherapy. The pathways involved in angiogenesis and molecules that have been developed in order to combat angiogenesis are described in this paper.

Advanced ovarian cancer (AOC) is one of the leading lethal gynecological cancers in developed countries. Based on the important role of angiogenesis in ovarian cancer oncogenesis and expansion, we hypothesized that the development of an “angiogenic signature” might be helpful in prediction of prognosis and efficacy of anti-angiogenic therapies in this disease. Sixty-nine samples of ascitic fluid- 35 from platinum sensitive and 34 from platinum resistant patients managed with cytoreductive surgery and 1^st-line carboplatin-based chemotherapy- were analyzed using the Proteome Profiler^TM Human Angiogenesis Array Kit, screening for the presence of 55 soluble angiogenesis-related factors. A protein profile based on the expression of a subset of 25 factors could accurately separate resistant from sensitive patients with a success rate of approximately 90%. The protein profile corresponding to the “sensitive” subset was associated with significantly longer PFS (8 [95% Confidence Interval {CI}: 8–9] vs. 20 months [95% CI: 15–28]; Hazard ratio {HR}: 8.3, p<0.001) and OS (20.5 months [95% CI: 13.5–30] vs. 74 months [95% CI: 36-not reached]; HR: 5.6 [95% CI: 2.8–11.2]; p<0.001). This prognostic performance was superior to that of stage, histology and residual disease after cytoreductive surgery and the levels of vascular endothelial growth factor (VEGF) in ascites. In conclusion, we developed an “angiogenic signature” for patients with AOC, which can be used, after appropriate validation, as a prognostic marker and a tool for selection for anti-angiogenic therapies.