Thirty years ago, Judah Folkman, of Children’s Hospital Boston and Harvard Medical School, first developed the idea that cancerous tumors are dependent on the growth of small blood vessels. Since then, Folkman and other researchers have sought a way to block the growth of cancer tumors through restricting or eliminating the small blood vessels that feed them. A new discovery made by a team of researchers working at Beth Israel Deaconess Medical Center (BIDMC) in Boston offers one of the first explanations for how angiogenesis – the medical term for the growth of small blood vessels – is inhibited in the body. The study focuses on a protein called tumstatin. Senior author Raghu Kalluri is a researcher in the Department of Medicine and the Program in Matrix Biology at BIDMC and associate professor at Harvard Medical School. The study appeared in the Jan. 4, 2002, issue of Science. “This is a very important advance in the fields of angiogenesis research and cancer biology,” said Folkman. The study was supported in part by grants from the National Institutes of Health (NIH) and research funds from Beth Israel Deaconess Medical Center.