1.   However, Cheresh noted that tumors produce such a wide variety of angiogenic proteins that neutralizing one of them has little effect.

2.   No one knows why tumors produce substances that inhibit angiogenesis as well as others that promote it.

3.   Since most brain tumors produce symptoms, like headaches, that are commonly caused by far less devastating disorders, they are often ignored or dismissed as unimportant.

4.   Through many years of pioneering research, Folkman discovered that tumors produce substances that induce angiogenesis, and, more surprisingly, substances that suppress the process.

5.   He contacted Australian team doctor Tony Galvin, who explained that tumors could produce different types of hormones and ordered further testing, including ultrasound.