It never occurred to me that cancer could be a natural default condition that is suppressed in multicellular life but that is what Paul Davies and Charles Lineweaver are suggesting.

Briefly: Normal cells will divide a number of times and then die. This programmed cell death is called apoptosis. Cancer cells are cells that wont die. Early eurkaryotic cells had no use for apoptosis. That was a development of multicellular life. Failure of apoptosis may be a reversion to the earlier state. IOW cancer is built into the genes.

www.iop.org/news/13/jul/page_60392.html