I wonder if this assumption is correct. The altered cells may be abnormal enough in activity to trigger apoptosis or they may be aberrant enough in surface molecular presentation to prompt destruction by the immune system. Either or both would weed them out fairly quickly, and they don't say whether they could still function correctly as hepatic cells. Failure to blend in and at least perform some normal functions would just get them sorted sooner. It does not appear that the altered cells would bear the necessary mutations to become cancer cells (yet) eitherAs far as permanence unless someone comes up with a gene therapy to change the dna of the impacted cells they will continue to reproduce with their new code. How is that not permanent?