Epigenetics is defined as functional and inheritable changes in the regulation of gene activity and expression without altering the primary DNA sequence, which is dynamic and susceptible to environmental exposures. Epigenetic regulation includes DNA methylation and demethylation, as well as posttranslational modifications of histones, chromatin remodeling, nucleosome positioning, and non-coding RNAs. Both epigenetic and genetic alterations contribute to cancer initiation and progression. In the process of tumor formation and development, epigenetic alteration has increasingly attracted attention. Aberrant epigenetic regulation contributes to cancer development through its involvement in tumor growth, apoptosis, senescence, invasion, metastasis, stemness, and drug resistance.

Similar to cancer genetics, cancer epigenetics has advanced due to high-throughput technology to characterize the epigenetic changes at the global and single-molecular levels. Epigenetic alterations may promote genetic mutations and genomic rearrangements in cancer, although the mechanisms involved are yet to be elucidated. A greater understanding of epigenetics and the therapeutic potential of intervention into these processes is necessary to help clinical treatment of cancer. More importantly, there are quite a number of scientific and pragmatic challenges to discovering epigenetic drugs as we are just beginning to understand the complexities of epigenetic events.

The aim of this Special Issue is to collate findings associated with epigenetic factors as ‘drivers’ or regulators of tumorigenesis. We welcome both original research and review articles.

Potential topics include but are not limited to the following:

• DNA methylation in cancer
• Histone modification in cancer
• Non-coding RNA in cancer
• Epigenetic reprogramming in tumor metastasis
• Epigenetic alteration in cancer chemoresistance
• Epigenetic factors as therapeutic targets
• Epigenetic factors as diagnostic markers
• The development of compounds that target enzymes involved in regulating the epigenome
• Epigenetic regulation of cancer stem cell formation and maintenance
• Epigenetic regulation of tumor microenvironment