A cell line that is under control

3T3 cells were established after a temporary dip in reproductive ability (top); once established they entered a resting state at a low cell density (bottom). G RE EN George Todaro and Howard Green establish the 3T3 cell line— the first well behaved, contact-inhibited cell line. In this mess of uncontrolled growth it was difficult or impossible to pick out cells that had been transformed after infection with oncogenic viruses, thus slowing the study of this transformation process. Todaro and Green (1963) took a different approach. “I wanted to do an experiment that somebody else could reproduce,” says Green. He and Todaro controlled