Leech and Rogue, absolutely!
Beast's self experimentation, yes!
Hope, perhaps...
Mutant or not, most of 'us' are our own X-aminers...but what's being tested and what's to achieve?
In many ways Xavier's credo and Sinister's too are 'cures' for a made illness...the sense of wounds and infection...the inward bend of the barb and blame.
But these characters are not cures. These powers and empowerments are at root highly altruistic and in that way deeply personal inter-social manifestations of a people...of an us that is in contrast and conflict to the us and them and the me who is not the I said to be me.
God Loves Man Kills gets to the heart of it...and in that way...in the sense of genocide, acculturation and assimilation...the concept of 'sick' and 'corrupted'...hmmm, remember the issue of Uncanny where Mesmero makes circus freaks out of the ANAD X-Men...that issue...
I don't know if I like the 'cure' concept but it's very much a part of our society today. Even if it's not explicitly enforced or spoken to, it is there in the patriarchy, here in the world of commodity, gain, possession and profit...here in the law stated and street block imposed - from there on the other side, over the fence, in the keep off the grass in the 'not in my backyard' compounds of what's deemed healthy and well and suited to say, to themselves, from aisle to aisle inside the castles of the kingdom...what the subjects should be, where they should be, and by what means they should address themselves.