Just like normal tissue, tumors need blood vessels to grow. Because of this, drugs that stop angiogenesis, or the formation of new blood vessels, are one important approach to treating cancers. These angiogenesis inhibitors stop tumor growth by starving them of oxygen and nutrients, usually by interfering with signals from the tumor cells that promote blood vessel formation in the surrounding tissue. Angiogenesis inhibitors have been shown to be effective in the treatment of several cancer types, but the results aren’t always as expected. Several recent studies show how complicated this can be. For instance, FDA approval of the drug More >