One might happen from random mutation or low level of a carcinogen, but all three genes suddenly deciding to mutate all at once in the same cell is unlikely. The more molecules you have interacting with DNA in a given cell, the more likely that you'll get the critical mutations. Some families have one of these genes already mutated-genetic predisposition. Then they only need one or two mutations. You may remember that a promoter isn't carcinogenic by itself, but if you give it to someone with a preneoplastic lesion it might make that lesion grow.
Promoters generally increases growth, cause more cell division.
Remember I mentioned that some carcinogens, when assayed at high concentrations, may fail to cause cancer because they kill instead of mutating. The opposite may be true of promoters. Example- saccharine at low concentrations is pretty safe. Cell death followed by regeneration has a promoter-like effect. The mechanism, however, has nothing to do with normal use.