[ulbu]

evolution is a wrong concept to approach it. cancer is not a separate life form, but a bug in the regeneration system of a complicated life form. it doesn’t exist outside of it, it cannot propagate.

[epistasis]

Cancer researchers generally refer to it as evolution, and I've never heard any complaints from the population geneticists or evo-devo folks about it, so I don't think it's a tremendously controversial way to talk about it. See for example

https://www.nature.com/articles/s41586-019-1907-7

[nly]

You might want to read this

https://en.wikipedia.org/wiki/HeLa

[8note]

the single celled dog might beg to differ.

sometimes a cancer can then survive on its own back as a single celled organism

[throwaway81523]

I've heard that some cancers spread by viruses. Viruses do evolve. No idea if that says anything about cancer evolving.