DNA damage can lead to the deregularization of various cell mechanisms, the ability of the cell to repair DNA being one of them. Only when several of those mech

DNA damage can lead to the deregularization of various cell mechanisms, the ability of the cell to repair DNA being one of them. Only when several of those mechanisms go rogue you get cancer; having only one or two of them disabled is usually not sufficient. In your example, an immortal cell who cannot repair DNA or even identify damaged DNA wouldn't be that dangerous, since it doesn't have the signal to reproduce wildly. See D. Hanahan and R. Weinberg "Hallmarks of Cancer: The Next Generation" for a scholarly (and quite readable) review http://www.sciencedirect.com/science/article/pii/S0092867411001279 http://www.sciencedirect.com/science/article/pii/S0092867411...