WHY ARE iPS CELLS A BIG DEAL? “Cell differentiation was seen as final and irreversible. Once a cell became specialized … It was considered locked-in and unable to become any other cell type. However, in 2006, scientists reported that they had turned a differentiated cell back into a stem cell with the potential to become any type of cell in the body.”
http://learn.genetics.utah.edu/content/stemcells/ips/