#1, Vitamin D is not a hormone. It's a vitamin. HUGE difference. While it's great for people who get little or no sun exposure, or don't drink milk enriched with it, it does not kill cancer.
If it did, nobody would die from skin cancers caused by the sun, would they?
Please don't fall for every quack on the market. This man will get rich, and you will die. It's sad to be this desperate. I know, I've had breast cancer, but this kind of shit makes me mad.