Researchers continue to put induced pluripotent stem cells (iPSCs) through their paces: "iPSCs, discovered in 2006, are derived by reprogramming adult cells into a primitive stem cell state. They are similar to [embryonic stem cells (ESCs)] in terms of their ability to differentiate into different types of cells in vivo, including endoderm cells that give rise to liver and lung tissue. ... induced pluripotent stem cells (iPSCs) can differentiate into definitive endoderm cells, in vitro, with similar functional potential when compared to embryonic stem cells (ESCs), despite minor molecular differences between the two cell types. These findings are particularly important given growing controversy in the scientific literature about whether subtle differences between iPSCs and ESCs should dampen enthusiasm for iPSCs to serve as an alternative source of differentiated precursor cells for various tissues, such as the liver, lung or blood. The new work provides compelling evidence that iPSCs have potential in regenerative medicine as an investigational tool for the development of treatments against diseases that affect endodermal-derived organs, such as cirrhosis, diabetes, cystic fibrosis and emphysema."