Why do cancer cells multiply and take over the body.

It's not a moral question, it's a scientific approach to a problem that we want to solve.

And how do you fight cancer? You kill every cancer cell. You don't negotiate with the cancer cells. You don't try to find out what it is they want. You don't ask how you've offended the cancer cell. You don't try to buy them off with money. I If cancer has attacked you (as Iran has attacked us), you fight and kill them. End of story