RHOH and sarcoma: Since we were able to show that cells forming the tumor vasculature, such as endothelial cells and tumor cells, can be rendered pro-coagulant by radiation-induced externalization of PS and thereby can increase the pro-coagulant activity of tTF-NGR, we have tested combination therapy with tTF-NGR and regional tumor irradiation in a human sarcoma xenograft system in vivo.