In a developing animal, stem cells proliferate and differentiate to form the organs needed for life. A new study shows how a crucial step in this process happens and how a reversal of that step contributes to cancer. The study, led by researchers at the Ohio State University Comprehensive Cancer Center-Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, shows for the first time that three proteins, called E2f1, E2f2 and E2f3, play a key role in the transition stem cells make to their final, differentiated, state. These proteins help stimulate stem cells to grow and proliferate. But...