Table 3.

Trends, opportunities, and challenges in the cancer epigenetics and epidemiology field

Most of the studies have been conducted using methylation markers.Integrate epigenetic research with genetics, environmental predisposition, and lifestyle factors.Follow an individual's epigenomic status, which changes spatiotemporally and compartmentally in tissues, and contributes to variations.
The majority of the exposures evaluated for their impact on the epigenome were nutrition, smoking, drugs and treatments, and infectious agents.Incorporate epigenetics into epidemiologic studies of cancer and the environment, which could contribute greatly to our understanding of cancer risk and development.Improve strategies for epigenetic data analysis and interpretation.
Most of the studies investigated epigenetic changes at specific individual loci, and very few studies explored changes at multiple loci or interactions among multiple loci.Determine the stability of epigenetic marks in repeated biospecimen samples from the same people over time.Conduct large-scale epidemiologic studies to determine whether epigenetic changes detected using blood samples accurately reflect both inherent and acquired epigenetic changes that contribute to cancer risk and impact outcomes.
Few investigators explored histone modifications along with methylation, nucleosome remodeling, or miRNA expression changes in cancer epidemiology.Explore the use of epigenomic information to better define cancer subcategories.Identify new chromatin abnormalities and their association with cancer.
Most epigenetic studies have been conducted in blood, which may not be an appropriate biospecimen.Develop improved strategies for epigenetic data analysis and interpretation.Develop high-throughput technologies for histone modifications and nucleosome remodeling.
Conduct studies that examine the relationship between epigenetic marks in germline DNA and tumor DNA.Distinguish between association and causality of epigenetic mark with disease.
Characterize all the components of theepigenome, which might help to understand the underlying mechanism of cancer risk and identify new biomarkers of cancer initiation and development.Evaluate relationships between epigenetic marks in germline versus tumor DNA.
Develop technologies that require small amount of samples compared with the amount currently used which might help to analyze multiple biomarkers in small samples.Distinguish age-related epigenomic marks with cancer-associated marks.
Use exposomes with information on well-defined factors (tobacco, diet, occupational exposures, and environmental pollutants) and omics profiling (genomics, transcriptomics, epigenomics, and metabolomics) for evaluating environmental exposure and cancer risk.Synthesize monoclonal antibodies for histone modifications (currently available antibodies have low dynamic range).
Understand the role of epigenetics in interaction of cancer-associated infectious agents with host factors.Develop technologies that use smaller amounts of sample for epigenomic profiling.
Use resources such as family registries in identifying cancers that tend to cluster in families.Increase in funds to conduct studies on epigenome-wide association studies.
Determine for how long longitudinal measurements should be taken in individuals at high risk before the disease develops. Two unresolved issues are: (i) whether epigenetic marks are transmitted intact from parent to offspring; and (ii) can we develop an epigenetic transmission test comparable with the transmission disequilibrium test used in genetic epidemiology.
Consider confounding factors between the epigenome and increasing age and tissue heterogeneity.