I saw that as well, but dug a little deeper. This book looks interesting:
http://yourcancerquestions.com/cancer-books/world-without-cancer-the-story-of-vitamin-b17
Sometimes I wonder what info the Multi Billion drug industry can control to protect their interests. Any food, drug, supplement taken in huge doses can be damaging to your body.
That said, I am new to all this cancer info and can be remarkably obtuse about same. JF