The antiangiogenic agents TNP-470 and 2-methoxyestradiol inhibit the growth of angiosarcoma in mice

Background: Endothelial malignancies, such as angiosarcoma and hemangioendothelioma, are often resistant to chemotherapy and surgery, and may result in death. Improved means of therapy are needed for these disorders. Objective: We wanted to determine whether angiosarcoma can be treated with angiogenesis inhibitors in mice. Methods: Mice were inoculated with a cell line that gives rise to angiosarcoma and were treated with the angiogenesis inhibitors 2-methoxyestradiol and TNP-470. Response to therapy was monitored by measurement of tumors. Results: TNP-470 caused an 84% reduction in tumor size, and 2-methoxyestradiol caused a 68% reduction in tumor size. Conclusion: Angiogenesis inhibitors are highly effective in treatment of angiosarcoma in mice. Clinical trials of these agents in humans with angiosarcoma and hemangioendothelioma are warranted.