No, I don't think so. Cancerous cells don't win at evolution. In fact, is they manage to kill the host, they explicitly lose.
Survival of the fittest doesn't prove the non-existence of broken bones, either.
It seems to me that the better argument is more along the lines of "bodies put a lot of effort into policing competition among their constituent parts" and "bodies put a lot of effort into repelling invaders." It is actually amazing that multicellular organisms overcome the prisoners' dilemma type situations, and there are lots of mechanisms that work on that problem, and amazing that pathogens don't kill more of us than they already do.
And when those mechanisms fail, the problems are just as dire as one would expect. Consider something...
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
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