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