well i already said they are not necessarily a "cure" for cancer, but more of a preventative means...however there have been quite a few studies that show diet treatments to be more successful and a lot less risky than the typical.
but thats also one of the problems i have regarding this type of stuff....just because you are studying nutrition in university or wherever, doesn't really mean too much (im trying not to be too offensive). but you are learning what they are teaching you, that is all. and the same goes for when you ask professors, they just learned what the university/curriculum whatever taught them. theres more information than just that. even then it differs between schools and between dietary ideas...thats why theres so many out there, and everybody thinks they are right.
i believe our diet (or lack there of) is a major cause of cancer, but not necessarily every time/kind/etc...its hard to say because we haven't been able to research it completely due to the myth that its all caused by global warming or aerosol cans or burnt toast...there are many effects and things in this world harmful to us, but we are unable to fight them off properly without the proper diet and immune system we should and could have.
i also think we are completely limited to what we can do today, diet wise, since our food supply has been cut to the bone in order to make more profits etc. what we eat is contaminated and altered in ways to maximize shelf life and make it more convenient (instant mashed potatoes) blah blah.
and there is lots of evidence (solid fact actually) that shows mere vitamins outright CURING other diseases with just large doses of vitamins. But not just vitamins, oxygen has amazing curing properties as well. it all ties together with other things i'd love to be able to talk about on this forum, and its quite amazing