Everyone's body has mutant cells in them all the time. In most cases the body rejects these cells and the body removes them. When for what ever reason the body doesn't fight off the mutant cell and it multiplies that is when cancer forms.
I blame California. Everything causes cancer there. Heck, I found electrical tape one time that had a carcinogen warning on it. AND I just heard on the news this morning that those beaker-brains now think the dye in Pepsi causes cancer! Pff!
cancer is a rapid, unhealthy growth of cells.... it can be caused many things for instance the sun. when a person gets too much sun their cells starts to mutilate and cells divide and do all sorts of crazy things. it is simply science. one might ask why humans just came about all of a sudden... or the earth even. cancer is just a part of life and death.