Human cancer may be thought of as Darwinian evolution of cells within the body (somatic evolution). As such, it may be modeled using evolutionary game theory. Winners in this game are able to maintain viable population numbers while losers go extinct. A model for somatic evolution is presented that shows how cancer can evolve to become a winner in this game. Associated with the model is an adaptive landscape that illustrates the evolutionary potential of cells as a function of adaptive parameters used by cells. Normal cells have a novel adaptive landscape that permits coexistence of invading mutant phenotypes. A mutant cellular population needs not immediately form a malignancy due to the existence of cellular constraints that results in limited growth and non-lethal coexistence. However, this coexistence deforms the local adaptive landscape resulting in an unoccupied fitness peak. The existence of this peak provides the potential for evolution to drive the mutant cells from simple coexistence to an evasive cancer. The model presented here suggests all that is required to accomplish this result is the relaxation of constraints that normally prohibit cells to evolve.
