I have been studying the work on cancer of the Italian researcher Stefano Fais. You can find a recent review of his work at this link. Basically, Fais sees tumor cells as the result of an unbalanced metabolism that leads these cells to develop on their own, even using anoxic processes to grow. He maintains that it is possible to slow down the development of these cells by making their metabolic growth processes more difficult, in particular using proton pumps to make their local environment more basic.
I am not expert enough to be able to give an informed judgement on these ideas. But, as you may imagine, it led me to consider if there were a link between cancer and the concept of holobionts and, yes, there is a line of research in this area. Several researchers seem to be exploring the idea that cancer is the result of a "dysbiosis," that is an unbalance of the host's microbiota. For instance, in a 2014 work by Apidianakis, we can read:
".... the host genetic background and that of the microbiome, define the intestinal hologenome, which is influenced by age and the environment toward homeostasis or disease. Thus, the intestinal disease may ensue when the intestinal hologenome is imbalanced, that is, when a genetically predisposed or old host interacts with its dysbiotic microbiota in an inadequate or harmful dietary or lifestyle-shaped environment."
The problem, here, is that there is no link whatsoever with Fais's idea that tumors are related to acidity. Maybe there is a link, somewhere, but the story is horribly complicated and I leave it here. It is just a note that you may find interesting and perhaps worth studying in depth.
