X-ray irradiation induces subtle changes in the genome-wide distribution of DNA hydroxymethylation with opposing trends in genic and intergenic regions.

DNA hydroxymethylation has gained attention as an intermediate in the process of DNA demethylation. More recently, 5-hydroxymethylcytosine has been recognized as an independent epigenetic mark that can persist over time and that exerts influence on gene regulation and other biological processes. Deregulation of this DNA modification has been linked to tumorigenesis and a variety of other diseases.