I think pinning it on one thing or another is probably rudimentary. It's probably thousands of variables, some greater than others. If we adhere to diets that correlate with health and longevity, or revert back to what it was like before the increase in cancer rates, we have a better defense system. There are more variables than just diet though. Environmental factors, stress, and nutrient-depleted soils to name a few. Eat real food that eats real food.