It wouldn't work. Cancer is basically a disease where developmental programs are expressed in cells uncontrollably. If you'd want to clone a healthy animal, you would definaltely need normal genome as a starting material for the developmental programs to work properly.
Besides, for a cancer you'll need more than than just one mutation. First you'd need a mutation in the apoptosis cascade to stop the cell from killing itself. Second you'd need a mutation to increase the proliferation of the cell, either by over expressing oncogenes or by silencing tumor suppressor genes. Next you'd propably have a mutation in the DNA repair machinery to facilitate accumulation of further mutations. Fourth would propably be some kind of metabolic mutation to allow tuomors to grow under low oxygen conditions (the diffusion of oxygen would limit the size of tumors, see Wartburg effect
). And finally, if cancer is considered to be malignant, you'd need some mutation to break the tissue integrity.
So, to sum it all up: It wouldn't work, and you wouldn't be getting any monsterous mutant creatures or zombies or anything