Expressions will change as the host has certanly a diffrent metabolism and hormon levels, in addition to possible epigenitic changes.

I think: that genetic treatment of a organ is currenlty not possible. Your goal would be to remove all immuno activating markers and replace them with the host ones. But for that to happen the old markers have to be removed which commonly happens when the cell dies. A duplication of a treated cell wouldn't solve the issue either at first iteration as the old markers would still be present, just their concentratio n per cell would be lower. With following iterations and natural removal of the old markers there would probably be a state achieved that would be ideal for tranplant. But dead and duplication can have big inteervals, like sure if you would take gut it would take just a couple days to get there but with a kidney or liver it would take years if not decades. Keeping a organ alive for that long would be a big achievemen.

You might then thing, yeah lets just do it in the donor, but then you get the same issues with a immune reaction, but now just on the donors side.