Ageing and cancer as diseases of epigenesis.

ABSTRACT

Cancer and ageing are often said to be diseases of development. During the past fi fty years, the genetic components of cancer and ageing have been intensely investigated since development, itself, was seen to be an epiphenomenon of the genome. However, as we have learned more about the expression of the genome, we fi nd that differences in expression can be as important as differences in alleles. It is easier to inactivate a gene by methylation than by mutation, and given that appropriate methylation is essential for normal development, one can immediately see that diseases would result as a consequence of inappropriate epigenetic methylation. While fi rst proposed by Boris Vanyushin in 1973, recent studies have confi rmed that inappropriate methylation not only causes diseases, and it also may be the critical factor in ageing and cancers.