| MadSci Network: General Biology |
There are already several lines of mutated cancer cells (we call them clones) that can live outside the human body, but they have to be maintained very carefully in cell culture (in a laboratory). The interesting thing about cancer cells is that they replicate continuously, so some cancer cell clones have been kept alive for great periods of time - the HeLa cancer cell clone line has been around for well over ten years! They can't live by themselves, though. A cancer cell is fairly specialized, being derived from a very specific kind of tissue (epithelial tissue, or connective tissue etc. etc.). It's just a specialized cell from the tissue that goes haywire and can't stop dividing due to an impaired 'mitosis-watching' gene (there are several). So essentially, a cancer cell derived from epithelial tissue will divide out of control, but it will still be an epithelial cell - not the kind of cell that can live on its own like a protist. As far as classification is concerned, the cancerous cell lines that have been isolated from individuals and maintained are called just that: clones or cell lines. The useful thing about maintaining these cell lines is that scientists from all over can do experimental cancer research an THE EXACT SAME KIND OF CANCER, for instance, a scientist in California and a scientist in France can both work on cells from the HeLa clone, and will be able to compare their results.
In case you're interested, Clive Barker, master of the Macabre did write a gothic fiction (read: illustratrated like a comic book) story where a cancer did kind of become its own creature and went around wreaking havoc - I think the name of the book is "Son of Celluloid" (Eclipse Books, 1991).
Good luck! Cool question!