Neovascularization in Ewing's sarcoma.

Ewing's sarcoma is the second most common bone malignancy in adolescents and young adults after osteosarcoma. Similar to other solid tumors, Ewing's sarcomas require an adequate vascular supply to grow and survive. The development and maintenance of vascular supply is accomplished via three main mechanisms; angiogenesis, vasculogenesis, and tumor cell vasculogenic mimicry. In addition, growth factors, parallel biochemical pathways and the tumor microenvironment are implicated in the initiation and maintenance of neovascularization. This article summarizes the different mechanisms and factors that contribute to neovascularization in Ewing's sarcoma, and discusses the significance of this phenomenon for current treatment options.