There are a handful of animals, mammals even, that essentially don't get cancer (some/all large whales and naked mole rats IIRC). So that might be solvable other ways.

Nitpick, it is far less likely, but they can still get cancer.

Cancer is not fundamentally unsolvable (AFAIK?). This is a tough question to answer though. Can we prove cancer to be solvable without solving it?

You also fix the copying errors.