American physician who helped discover a possible treatment for some types of brain cancer using compounds from the liver of a type of shark. The compound, called squalamine, is an angiogenesis inhibitor, meaning it interferes with a tumor's ability to cause the growth of new blood vessels necessary to feed it as it expands. This, in turn, may help to limit the growth and spread of tumors, holding the promise of a treatment to limit the severity of some types of cancer.