[onemoreact]

Cancer is a series of mutations that enable a single cell to out compete other cells in the body for resources and reproduce exponentially. The final stage of cancer is generally some cancer cells that learn how to travel though the body and end up in a new location. However, rather than a simple disease it's an evolutionary process than can result in a brand new parasite as long as the cells learn to adapt outside the original host. http://en.wikipedia.org/wiki/Devil_facial_tumour_disease

Warning, clinking on that link may give you nightmares.

[majmun]

could this be how some viruses were started?