Selection, the mutation rate and cancer: Ensuring that the tail does not wag the dog

In considering tumorigenesis, much attention is paid to genome instability and mutation rates. While reflecting on the circumstances that have led to this emphasis on mutation rates, Ian Tomlinson and Walter Bodmer point out that an increased mutation rate does not necessarily cause a tumor to grow and that selection is in fact the mechanism that drives the cellular, somatic evolution that leads to cancer.