Non-CpG methylation—a key epigenetic modification in cancer

• Published in: Briefings in functional genomics Vol. 20; no. 5; pp. 304 - 311
• Main Authors: Ramasamy, Deepa, Deva Magendhra Rao, Arunagiri Kuha, Rajkumar, Thangarajan, Mani, Samson
• Format: Journal Article
• Language: English
• Published: 11-09-2021
• ISSN: 2041-2649; 2041-2657
• DOI: 10.1093/bfgp/elab035

The methylation of cytosine residues that precede adenine/thymine or other cytosine nucleotides instead of guanine in DNA is known as non-CpG methylation. It is a pronounced epigenetic modification with a central role in gene regulation similar to CpG methylation. Due to technological limitations, the locus-specific role of non-CpG methylation was scarcely understood. At present, high-throughput analyses and improved enrichment methods can elucidate the role of genome-wide non-CpG methylation distributions. Although the functional basis of non-CpG methylation in regulating gene expression control is known, its role in cancer development is yet to be ascertained. This review sheds light on the possible mechanism of non-CpG methylation in embryos and developed tissues with a special focus on cancer development and progression. In particular, the maintenance and alteration of non-CpG methylation levels and the crucial factors that determine this level of non-CpG methylation and its functional role in cancer are discussed.