Irving Weissman, professor of developmental biology at Stanford University Medical Center, addresses what cancer stem cells are, how they maintain themselves and why they may be resistant to some current treatments. Weissman also talks about the "don’t eat me" signal and how it relates to the growth of certain types of cancer cells. Find out how Stanford scientists and clinicians are working to identifying cancer stem cells in many types of tumors and how they have used that information to develop new therapeutic strategies. From the Series:The Stanford University Medical Center Health Hour