Cancer is normal development spun out of control. It is the great plasticity and power of development, without the overarching controls that guide normal development toward an integrated adult form. Instead, whenever a newly developed kind of tissue acquires the ability to survive, grow, and resist control, there is nothing to stop it. That may be why normal adult cells are often terminally differentiated into a restricted cellular program. And it may be why wound healing, which releases the restricted cellular program and powerfully plastic tissue remodeling, is so tightly regulated and, when dysregulated, so often associates with cancer. With regard to evolutionary history, humans develop differently from their ape ancestors, and their lifestyle causes them to suffer different kinds of tissue damage. Those differences in development and wound healing likely led to new aspects of cancer disease over human history. (#40691)