The bottom line is that you cannot explain, mathematically, how you can get cancer from random mutation of your DNA. The odds are astronomically small so that cancer would be incredibly rare and no two cancers would be the same. That is not what we see, instead cancer seems to be growing exponentially and millions of people have the same cancer.
However, if cancer is simply a fungal infection and we are surrounded by a variety of fungi all the time and all you need is to weaken the immune system so that the fungus can get a foothold well then that would explain millions of people getting cancers that are similar, it would explain why some are in the blood, others in the lungs, and still others in digestive tract. It would also explain why we could have so many different carcinogens.
It would also explain why treatments that treat cancer as a fungal infection have a great track record at a tiny fraction of the cost of American medicine. Things like ESSIAC
I fully agree with this. Whether cancer is caused by the body's own defence mechanisms, by parasites or by fungi, I am certain that the one thing it isn't caused by is random mutations. As you correctly describe, were cancer caused by mutation, it would be incredibly rare and each one would be different. More likely, the mutation is caused by the cancer (not the other way around).
In times past, some doctors have claimed a link between vaccines and cancer (I believe one said he had never seen a case of cancer in a (totally) unvaccinated patient).
My theory at present is that cancer is the body's own defence mechanism. The parasites and fungus are there as their purpose is to clean up the mess, and they're trying to do that, but not actually the cause of the cancer. I don't think this explanation holds up well with cancers going malignant and spreading when disturbed (perhaps the body's defences are already in overdrive, and fungi/parasites are a part of the problem but not the root cause?)
Things like poisons in chemicals, radiation, vaccines etc. may trigger the body's defense mechanism when lesser means fail (bacteria and exosomes). I don't buy the virus explanations, as I don't believe viruses have ever been proven scientifically to exist independently (i.e. they are produced by the cells).