I think cancer is a more specific concept than just "unregulated growth." Cancer is a phenomenon that occurs when a valid "self-replicate then die" program has a similar encoding to a "self-replicate indefinitely" program, such that random-noise damage to the program's stored representation can result in the former being rewritten into the latter.

Whether or not the substrate is biological, I would think that you'd still have to worry about ensuring your program is encoded in such a way that the part of it that turns it off can't be damaged without disabling the program as a whole.