The role of prostaglandins in tumor-angiogenesis.
Angiogenesis is growth of new blood vessels from preexisting vessels and capillaries.
Angiogenesis is an important physiological process in embryogenesis, wound healing repair and female estrus. However, this phenomenon occurs, as a pathological process, in chronic inflammation, fibroproliferation, and tumorigenesis. After a new tumor has attained a small size of a few millimeters in diameter, further expansion of the tumor cell population requires induction of new capillary blood vessels. The process of neovascularization is regulated by numerous growth factors generated by host stromal cells including macrophages and mast cells. In the solid tumor, the microenvironment is the space limited by the basement membrane of the microvessels and the neoplastic cell membrane.