Interesting. I am surprised that the skin cell from the patient -> stem cell -> liver cell -> was injected into mice and that the cells were still working after 6 wks. The article does not say whether these were immunodeficient mice. Nevertheless, the proof-of-concept is halfway there. I would caution that whatever happens in vitro (in a dish) is entirely different in vivo (in animals/humans). Induction of cancer by re-injected cells would certainly be a potential concern. However, the findings from this article do show enormous potential.