Use of ‘Omics to Elucidate Mechanism of Action and Integration of ‘Omics in a Systems Biology Concept.

This special issue of Mutation Research may demonstrate to the reader that 'omics technologies are beginning to take their place among other routinely used approaches for chemical hazard/risk assessment. This is because of the potential added value that 'omics data have been demonstrated to bring to the risk assessment process by improving mechanistic understanding and identifying modes of action. It is also promising that whilst transcriptomics may be more sensitive than analysing classical toxicology parameters, metabolomics appears to be at least equally sensitive. It is now generally accepted that no-observed adverse effect levels (NOAELs) can be obtained from 'omics studies if they are based on specific patterns of change for potentially relevant biological effects, i.e. patterns indicating perturbations of adverse outcome pathways that can be causally related to a toxic effect. Consequently, using any alterations in individual parameters from 'omics studies, e.g. at the single gene or metabolite level, is considered to be unsuitable for the derivation of NOAELs....