What can I do if I suspect that my Mycelium word list backup has been compromised? When creating a backup with the Mycelium app, it gives me a list of 12 words which are used as some form of seed which I am supposed to write down and store in a safe place. Anyone with access to this word list can access any current and future funds in the wallet.

Well, what if my safe place gets compromised and the list of words stolen - can I somehow cancel the backup and generate a new one? Or would I need to set up a new wallet and transfer my funds there and just abandon the old one?
There is no way to cancel the backup. Also you cannot be sure if it is comprised until the person actually spends the funds. 


Transfer the funds to a new wallet 
Diversify risk: Don't but all funds in one wallet !