IMO seed oils are a much bigger issue - causing mitochondrial damage which causes cells to revert to fermentation
Discussion
I've heard of the seed oil thing becoming a major talking point over the past few years, and I agree as far as that anything in excess is almost certain to be a hazard to your health, and while excessive use of oils in cooking (sans olive oil) is naturally bad for you, I've not yet found convincing evidence that oils, seed or not, is bad in any minor amount. I'll have to dig into it.
Also, fermentation happens in the large intestine, not inside the cells themselves.
Cancer cells (anywhere in the body) ferment glucose and glutamine
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4783224/
The question is what can damage mitochondrial function besides seed oil. Probably smoking, but not many other things. I would be surprised if properly cooked potatoes could do it, for example.