Vascular endothelial growth factor and its relationship to the prognosis and treatment of breast, ovarian, and cervical cancer

Tumor neovascularization is a complex process that plays a crucial role in the development of many different types of cancer. Vascular endothelial growth factor (VEGF) is a potent mitogen that is involved with mitogenesis, angiogenesis, endothelial survival, and the induction of hematopoiesis. By increasing vascular permeability in endothelial cells, it helps tumors recruit wound-healing proteins fibrin and fibrinogen from the plasma, suggesting that tumor formation is a process of abnormal wound healing dependent on the ability to generate a blood supply. The human female reproductive tract is highly dependent on VEGF for normal functions such as endometrial proliferation and development of the corpus luteum. The unique influence of female sex steroid hormones on the expression and activity of VEGF deems angiogenesis an important facet of the development of breast and ovarian cancer. Additionally, the up-regulation of VEGF by the E6 oncoprotein of the human papillomavirus suggests that VEGF plays an important role in the development of cervical cancer. Clinical trials have investigated the humanized monoclonal antibody bevacizumab as potential treatment for all three forms of cancer; the data show that in breast cancer, the use of bevacizumab may lengthen the disease-free survival for women with advanced breast cancer, but does not appear to change their overall survival. It may have a role as salvage chemotherapy for ovarian and cervical cancer, though further research is needed to establish it as a definitive form of treatment.