cell repair cycles and rebirth (c) RSThere are many factors in the war on or for cancer..
Replication of DNA can lead to some error they theorize but evolution happens that way.
In order to argue for the non cancer function of replication lets talk about sperm..
Spermatozoa rarely have defunct DNA even with millions of replications per spoonful :-)
So talking about replication error is marginal at times ... Obviously some changes do and can occur during sperm production, and the results are called evolution or problems..
Cancer cells themselves are living entities with functioning replication cycles
But first one must keep in mind that DNA is repaired during replication and that thusly cell division has advantages to a living host as well as the possibilities of transmitting an error...
In computer code there is a Key to a file that can be used to decide if the code was transmitted properly and in DNA this sort of thing undoubtedly exists to rectify blatant mistakes,
Small errors or completely missing code , probably not and so overall the message is because you remake the cell during division it is good for the host to divide.
However benefits from stable code when not reproducing mean its unlikely to create as many errors during gene copying, However basic functions are still carried out daily ; enzyme expression and other cell functions that clearly would lead to further problems ..
and of-course benefits like cell repair are more frequent during birth and reproduction.
Simply put cells replicate by design and so doing it is fundamentally safe guarded by evolutionary or creational flavor's :-)