What Makes Stem Cells Stem Cells? (broadcast Friday, February 22nd, 2008)

In the past few years, scientists have drawn several parallels between stem cells and cancer cells. In tumor formation, formerly specialized tissue cells somehow become 'reprogrammed' to form tumor tissue. A similar reprogramming takes place in the creation of stem cells. Both types of cells also have an unusual ability to renew themselves. So what is it that lets a stem cell know it's a stem cell, and not a cancer cell?

In this segment, Joe Palca talks with stem cell researcher George Daley 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 called “let-7 microRNAs” found in both stem cells and cancer. Teachers, find more information about using Science Friday as a classroom resource in the Kids' Connection.