The purpose of this research study is to learn the effects (good and bad) of an antiangiogenic therapy drug (drugs that stop new blood vessel growth and starve a tumor by cutting off its blood supply) called avastin. Avastin is an antibody directed against vascular endothelial growth factor, or VEGF. VEGF is a potent, specific growth factor with a well-defined role in normal and abnormal blood vessel formation. It is present in a wide variety of normal tissues, but is produced in excess by most solid cancers (tumors). In the setting of cancer, VEGF promotes the growth of blood vessels that bring nutrients to tumor cells. In laboratory studies, avastin has been shown to inhibit the growth of several different types of human cancer cells.