Infantile hemangioma research: looking backward and forward.

This is a remarkable time to be a student of infantile hemangiomas (IHs). IH is a common tumor, estimated to occur in approximately 4% of infants. Studied for many decades, the acquisition of knowledge and pace of IH research are accelerating. The article by Greenberger et al. in this issue is a welcome addition to the literature. It examines rapamycin as a possible treatment for IH that could potentially be curative because suppression of self-renewal of stem cells might deplete hemangiomas of the stem cells from which they originate. However, before we get too enthusiastic about using rapamycin for IHs, it is important to reflect on lessons learned from previous hemangioma therapies.