Cancer stem cells.

N Engl J Med 2006;355:1253-61. Copyright © 2006 Massachusetts Medical Society. The deepening of our understanding of normal biology has made it clear that stem cells have a critical role not only in the generation of complex multicellular organisms, but also in the development of tumors. Recent findings support the concept that cells with the properties of stem cells are integral to the development and perpetuation of several forms of human cancer.1-3 Eradication of the stem-cell compartment of a tumor also may be essential to achieve stable, long-lasting remission, and even a cure, of cancer.4,5 Advances in our knowledge of the properties of stem cells have made specific targeting and eradication of cancer stem cells a topic of considerable interest. In this article, we discuss the properties of cancer stem cells, outline initial therapeutic strategies against them, and present challenges for the future.