They are just cutting genes from one organism and planting them another.... the genes are from two very different species that do the exact same thing. They are simply planting a gene in the new organism, in this case (the tomato), and then it starts producing this chemical at a much larger rate and quantity. Seems pretty bad ass to me. If you could control the plant growth/reproduction ie. in a controlled greenhouse, then it wouldn't spread out into the wild.. There is a strong correlation between this chemical and not getting cancer.
Also, I am not "tripping" on purple food, hell I dont care if the food is glowing (as long as not radioactive), if it were to cut my chances of getting cancer or living longer with a cancer, id eat it. I think docs are saying something like 6-8 tomatoes, so that your body even gives a shit if you ate them. this would cut that to 1.