Challenges in the analysis of epigenetic biomarkers in clinical samples.

Epigenetic modifications represent an interesting landscape which can describe relevant features of human disease. Epigenetic biomarkers show several advantages as disease biomarkers because they provide information about gene function, specific endophenotypes and can even incorporate information from the environment and the natural history of disease. The improvement in genomic and epigenomic technologies has revolutionized the current comprehension of biological processes underlying health and disease. However, now is the time to adopt these new technologies to improve human health, thus converting this information into reliable biomarkers. This endeavor should be focused on improving methodologies to analyze gene methylation, histone modifications and microRNAs. Ideally, epigenetic biomarkers should be robust, routine, accurate and inexpensive in order to provide better information for patient diagnosis, prognosis, stratification and treatment monitoring. Here we describe some challenges and provide strategies to improve the adoption of epigenetic biomarkers into clinical routine. Furthermore, we summarize the recommended properties for clinical epigenetic biomarkers.