If there is one cause of cancer, it would be genetic damage to somatic cells. So all we have to do to cure cancer is prevent all genetic damage! That’s not a very useful prescription, unfortunately; it’s rather like saying that all we have to do to prevent accidental deaths is prohibit all potential causes of injury. The causes of genetic damage are ubiquitous.
We’re familiar with some. Smoking, for instance, irritates and damages the cells of the lung epithelium, and increases the rate of cancer incidence. UV radiation damages DNA, so prolonged exposure to the sun increases the rate of skin cancer. Chimney sweeps would get covered in the carcinogenic compounds present in soot, which would accumulate in folds of skin, and had phenomenal rates of scrotal cancer. So don’t clamber around in chimneys, stay in the dark all the time, and never start smoking, and you won’t get cancer, right? Wrong. You’ve eliminated some factors that increase the incidence of cancer, but not all. You might think that if we just eliminated every cause of genetic damage we’d be safe, except that there’s one we can’t get away from.
