Toxicogenomics

Toxicogenomics is a field of science that deals with the collection, interpretation, and storage of information about gene and protein activity within particular cell or tissue of an organism in response to toxic substances. Toxicogenomics combines toxicology with genomics or other high throughput molecular profiling technologies such as transcriptomics, proteomics and metabolomics. Toxicogenomics endeavors to elucidate molecular mechanisms evolved in the expression of toxicity, and to derive molecular expression patterns (i.e., molecular biomarkers) that predict toxicity or the genetic susceptibility to it.

This broad definition is supported by the United States Environmental Protection Agency stating that "the term "genomics" encompasses a broader scope of scientific inquiry and associated technologies than when genomics was initially considered. A genome is the sum total of all an individual organism's genes. Thus, genomics is the study of all the genes of a cell, or tissue, at the DNA (genotype), mRNA (transcriptome), or protein (proteome) levels. Genomics methodologies are expected to provide valuable insights for evaluating how environmental stressors affect cellular/tissue function and how changes in gene expression may relate to adverse effects. However, the relationships between changes in gene expression and adverse effects are unclear at this time and may likely be difficult to elucidate."

The nature and complexity of the data (in volume and variability) demands highly developed processes for of automated handling and storage. The analysis usually involves a wide array of bioinformatics and statistics. , regularly involving classification approaches.

In pharmaceutical Drug discovery and development toxicogenomics is used to study adverse, i.e. toxic, effects, of pharmaceutical drugs in defined model systems in order to draw conclusions on the toxic risk to patients or the environment. Both the EPA and the U.S. Food and Drug Administration currently preclude basing regulatory decision making on genomics data alone. However, they do encourage the voluntary submission of well-documented, quality genomics data. Both agencies are considering the use of submitted data on a case-by-case basis for assessment purposes (e.g., to help elucidate mechanism of action or contribute to a weight-of-evidence approach) or for populating relevant comparative databases by encouraging parallel submissions of genomics data and traditional toxicologic test results.

Public Toxicogenomics Projects

 * Chemical Effects in Biological Systems (CEBS) - Project hosted by the National Institute of Environmental Health Sciences (NIEHS) building a knowledgebase of toxicology studies including study design, clinical pathology, and histopathology and toxicogenomics data.
 * InnoMed PredTox assessing the value of combining results from omics technologies together with the results from more conventional toxicology methods in more informed decision making in preclinical safety evaluation.
 * Predictive Safety Testing Consortium aiming to identify and clinically qualify safety biomarkers for regulatory use as part of the FDA's Critical Path Initiative
 * ToxCast program for Predicting Hazard, Characterizing Toxicity Pathways, and Prioritizing the Toxicity Testing of Environmental Chemicals at the United States Environmental Protection Agency