Cancer epigenetics in clinical practice

Cancer development is driven by the accumulation of alterations affecting the structure and function of the genome. Whereas genetic changes disrupt the DNA sequence, epigenetic alterations contribute to the acquisition of hallmark tumor capabilities by regulating gene expression programs that promote tumorigenesis. Shifts in DNA methylation and histone mark patterns, the two main epigenetic modifications, orchestrate tumor progression and metastasis. These cancer-specific events have been exploited as useful tools for diagnosis, monitoring, and treatment choice to aid clinical decision making. Moreover, the reversibility of epigenetic modifications, in contrast to the irreversibility of genetic changes, has made the epigenetic machinery an attractive target for drug development. This review summarizes the most advanced applications of epigenetic biomarkers and epigenetic drugs in the clinical setting, highlighting commercially available DNA methylation-based assays and epigenetic drugs already approved by the US Food and Drug Administration.