Both stem cells and cancer cells have the unusual ability to renew themselves. In tumor formation, formerly specialized tissue cells become "reprogrammed" to form tumor tissue. A similar reprogramming takes place in the creation of stem cells. So what lets a stem cell know it's a stem cell, and not a cancer cell?
Stem cell researcher George Daley talks about the discovery of a protein that may help give stem cells their unusual multi-function abilities. The protein, named Lin-28, appears to help regulate the activity of certain small RNA molecules found in both stem cells and cancer.