Hemangiomas are benign tumors in which cells that line the blood vessels proliferate wildly, resulting in a tangled thicket of blood vessels. Approximately 1 out of 100 newborns develop at least 1 hemangioma and approximately 25% of premature babies develop hemangiomas.

Typically, hemangiomas exhibit a fairly predictable pattern of growth. They grow rapidly for the first 6 to 12 months of life, after which they begin a much slower process of shrinking, or involution, which may take from one to seven years. By the time a child reaches about 12 years of age, involution is almost always complete. For this reason, most hemangiomas require no treatment.

However, some hemangiomas develop near the eyes or on vital organs, where, if they become large enough, they may pose a threat to the child's vision or life. These often require treatment with interferon alpha, a drug that was discovered by Bruce R. Zetter in Folkman's lab in the 1980s to be antiangiogenic and was the first antiangiogenic agent to be used in humans. However, interferon isn't universally effective.

Joyce Bischoff and colleagues in the Vascular Biology Program are seeking to learn which factors stimulate the growth of endothelial cells and, more importantly, which factors inhibit growth. Identifying factors that inhibit abnormal endothelial cell proliferation in hemangiomas could suggest new treatments for the children who do not respond to current therapies.