Cancers are in all of us, all the time- they're misregulated cells growing wrong. Our bodies normally deal with them- unless they're under too much strain from other toxins and parasites etc. Our air, water and food, not to mention "medicine" and ever-increasing radiation, all attack our systems.

The antithelminics, antiparasitics all have been observed to have tremendous anticancer properties, and likely due to multiple reasons, one of which is anti-parasite activity. This is similar to zinc and vitamins having multiple beneficial paths, because there are a lot of cascades in our bodies and they weave into each other in complex ways.

The keys seem to be around re-establishing natural balance, and then maintaining it.