These are exciting times for discovering the biological scope and the mechanisms of action of DNA and RNA molecules, which have a great impact on tumors. Epigenetic modifications such as DNA methylation and histone modification play pivotal roles in development, cell differentiation, and cell identity. Inappropriate regulation of epigenetic mechanisms has been implicated in human cancers. Moreover, there has been a recent explosion of activity in the fields of RNA epigenetics and non-coding RNAs, which have become integral parts of the field of gene expression. Both genetic and epigenetic modifications contribute to determining the outcomes of regulatory gene expression systems.

Identifying genetic and epigenetic factors involved in cancer has proven to be a promising field of research, not only to improve the knowledge of risk factors for cancer, which could be of help for prevention, but also to improve the understanding and characterization of cancer, and to optimize and personalize the treatment. However, numerous factors are involved and the role of many of these are still poorly known. Since some genetic and epigenetic changes are significant in abnormalities during cancer development, the initial changes, dynamic and reversible properties, and diagnostic potential of genomic and epigenomic phenomena are subject to genome- and epigenome-wide association studies for therapeutic aims. The recent development of numerous small-molecule compounds of the genetic and epigenetic regulators is allowing to identify novel potential therapeutic approaches in the treatment of different malignancies. However, genetic- and epigenetic-targeted therapy still needs to be expanded and studied in order to understand the mechanisms to improve the clinical outcomes.

The aim of this Special Issue is to collate original research and review articles describing advances in this field.

Potential topics include but are not limited to the following:

• Novel mechanisms and small-molecule compounds of DNA methylation, and histone modifications in cancer
• Novel mechanisms and small-molecule compounds of RNA modification, especially RNA methylation, alternative splicing, and transcription-wide RNA modification in cancer
• Novel mechanisms and small-molecule compounds of non-coding RNAs, including miRNAs, lncRNAs, circRNAs, piRNAs in cancer
• Genetic and epigenetic changes as determinants of drug response and resistance
• Molecular profiling of genetic and epigenetic biomarkers to identify prognostic and therapeutic targets
• Computational tools for the detection of genetic and epigenetic subtypes
• Epitranscriptome bioinformatics, including but not limited to, in silico identification of RNA modification sites from primary sequences, novel computational approaches, and new software tools for analysis of high-throughput epitranscriptome profiling datasets, RNA modifications databases, and computational methods to predict RNA secondary structures and RNA interaction for modified RNA molecules