No it is not!
Evolution is a process of the filter of natural selection working on genetic variation of the genetic material which we pass on to future generations. Cancer is NOT an example of this process in any way shape or form. Cancer is an example of damage to our chemistry (particularly somatic rather than germline genetic material) by a variety of sources like chemicals (carcinogens), radiation, or pathogens.
(see suggestion of a different rewording of the claim below, to which I do not object)
Believe it if you like, but I do not. I am quite sure that the resistance which viruses have to the anti-viral defenses of other organisms is the product of a long history of evolution which evolves many different ways of introducing variation into the genome in a highly controlled manner to achieve highly tuned solutions to particular challenges. That is how the evolutionary algorithm works.
It is all far more intentional than some biologists make it out to be. Intentional but not a matter of intelligent design by a supernatural deity. Where do I get this from? From studies of mutagenesis, which for example find that organisms like E-coli have actually evolved mechanisms to bypass their own DNA repair process in order to introduce variation into their genome.
Incorrect. This is an argument of a THEIST objecting to the monster invented by those using religion for power over other people.
Well THAT is certainly correct! Cancer cells are alive too and also subject to natural selection just as all other living things are. The body has evolved defenses against cancer just as it has against pathogens and so unless a cancer cell can evade these defenses then they will not survive.
SO, if what glipsnort meant to say is that examples of the evolutionary process can be found in the phenomenon of cancer, then I have no objection to that claim. But, it is still very STRANGE to call these examples of evolution, since this is certainly not about the origin of any species – so it might even be better to call them analogies of evolution rather than examples of actual evolution.