Hypermethylation of the DNA is one of the simplest yet still very poorly characterized forms of epigenetic dysregulation in cancer. Adding additional methyl groups to a promoter of the gene simply shuts it off — and losing methyls on a promoter could turn a gene on. The simple mechanism explains how cancer can result when an oncogene is hypomethylated or tumor supressor gene is hypermethylated EVEN in the absence of DNA mutations.
The research done by a group at the University of Essen here links hypermethylation to CLL, adding to the index of clearly defined epigenetic changes that have direct clinical relevance. Understanding the process of tumorigenesis in this case provides a direct potential target for future therapies.