Chair of Department,
Johns Hopkins University, USA
Dr Fallin’s talk provided examples of the exposure biomarker opportunities for epigenetics, as well as the challenges that must be addressed to realise these opportunities.
Epigenetic marks can be useful for epidemiology and clinical medicine under multiple scenarios. Epigenetic machinery, such as DNA methylation, histone modifications and chromatin structure, controls regulation of when and where in the body particular genes are expressed. Thus, epigenetic marks can provide mechanistic insights about how genetic variation affects phenotype. Importantly, epigenetic marks are responsive to environmental changes, and thus may also be a mechanism for how exposures manifest disease, or how genes and environment work in concert towards a phenotype. Epigenetic measurement may also be useful as a biomarker of past exposure, even when the epigenetic changes are not directly causal of downstream phenotype. In this case, epigenetic biomarkers may be an attractive opportunity to estimate cumulative or specific prior exposure in situations where direct measurement of the exposure is not feasible. The question remains: Can we start to identify key biomarkers and potential mechanisms associated with the phenotypic adverse change? (Sound techniques, robust data interpretation procedures). The concept of ‘repeated exposure’ and possible links to epigenetic regulations ― with repeated dose studies introducing baseline responses and transient responses with possible link to epigenetics.