Q:

Cancer and Evolution

Edit: just to clarify, I am asking what, if anything, the literature says can be gleaned about evolution by studying cancer, especially relating to how multicellularity evolved and the traits used to force cells under control of the organism.  
Most of the original question details I had added were just my own thoughts on the topic.

Original question
Is there a sense in which cancer can be considered as a return to the unicellular "origin" of a cell?
It has always seemed to me like cancer is almost inevitable by the structure of the cell (its poor "design", essentially). The only thing standing in the way are the cellular controls: senescence/apoptosis (e.g. p53 pathway), immunosuppression (e.g. cytotoxic T lymphocytes), telomeres, etc...
So it seems like multi-cellularity did not evolve "ground-up", but was instead generated by slowly differentiating the functions of the various cells, while developing "top-down"controls against errant cellular behaviour.
Thus, cancer, which occurs when these protections fail, is in some sense merely a return to an ancient evolutionary root. 
I suppose some arguments against this include the fact that modern cells are vastly different than their ancient ancestors (or even modern archaea/bacteria). 
So the best we can perhaps say is that the core of the cell has been sufficiently preserved (ribosomes are still mostly RNA, are they not? :] ).
Further, it is hard to call some of the "micro-evolutions" of cancer (e.g. interleukin-8 production) as returns to primitive behaviour. 
In these cases, I tend to see them as necessary occurrences to remove the "top-down" controls, rather than as integral to the destructive out-of-control growth characterizing oncogenesis.
But, debatably, perhaps not all of them are (e.g. extravasation in metastasis).
Obviously this seems very simplistic, but is there any literature thinking about it this way? Or directly debunking it?

A:

Cancer and level of selection
Cancer results from the opposite action of different level of selection. There is selection on the population of multicellular individuals and there is selection on the population of cells within each multicellular individuals.
There is selection among cells within an individual for increase replication rate while there is selection among multicellular individuals in the population for controlled replication rate of their cells.
Major transitions
The passage from small unit of selection to bigger units is called a "major transition". Such transitions include the grouping of genes on chromosomes, the grouping of cells onto multicellular individuals, the grouping of multicellular individual onto colonies and, if there are several planets inhabiting life in the universe, then the grouping of life forms in every planet into a population of living planets. One can list other, more extreme or intermediate major transitions but there is quite a bit of debate on what really constitute a major transition.
Literature on the subject

[I]s there any literature thinking about it this way?

The keywords that will help search further information are group selection, kin selection, major transitions.
I recommend having a look at Major Transitions In Evolution by Maynard Smith and Szathmary and also The Major Transitions in Evolution Revisited by Calcott and Sterelny which is a book made of many small parts, each written by a different author on these same questions of level of selection.
You might eventually have a look at Evolutionary Dynamics: Exploring the Equations of Life  by Nowak as well.
These discussions of level of selection include discussion of what an individual is and what level is most important. The extremely popular and well written books by Dawkins will also bring you some light on the subject. Consider The extended phenotype for example.
For more book recommendations in evolutionary genetics, please have a look at Books on population or evolutionary genetics?.
If you like the sensation of thinking of the entire earth as an individual part of eventually a larger group of living planet, then you'll maybe enjoy having a physiological / ecological view of this living planet earth with Gaia by Lovelock

