[aeternum]

If you have a skin cell that incorrectly differentiated into a mole, how do you reverse it?

You can't just fix the DNA, it must also figure out whether it should become a hair follicle or one of the many subtypes of cells that make up your skin layers. We know that this differentiation seems to be controlled by ion/electrical signals early in life.

So a key question is: Why does differentiation accuracy seem to degrade with aging, and is there anything we can do to stop it?

CRISPR is pretty good at fixing DNA, we definitely need to optimize our use of that tool but at least there's a path. We really don't have a clear path to fix the differentiation/epigenome problem.