For the liver, what's so interesting is that there's no stem cell in the liver. So the normal liver actually can regenerate. It's one of the only organs in the human body that can do this, and we've known this since the time of Greek mythology.

For the liver, what's so interesting is that there's no stem cell in the liver. So the normal liver actually can regenerate. It's one of the only organs in the human body that can do this, and we've known this since the time of Greek mythology.

An interesting opportunity is actually not just thinking about building organs for patients, but actually building little tiny organs that you could do drug screening on.

In fact, if we cut 50 percent of the liver out, it'll be back in two weeks.