Division of Genetic and Molecular Toxicology
Provide internationally recognized expertise in developing, validating, and interpreting genetic toxicology research for regulatory decisions that improve public health.
Division Director: Robert Heflich, Ph.D.
Division Research Themes
- Develop and validate of regulatory genetic-toxicology assays
- Conduct chemical-specific research
- Develop new paradigms for regulatory decision-making that integrate measures of genetic risk with biomarkers of toxicity by conducting research to develop:
- Relevant biological models
- Comprehensive approaches to monitor genetic variation using technologies such as Next Generation Sequencing
- Better ways of evaluating data to determine human risk
Division scientists actively participate in FDA committees and international working groups that form consensus on how to conduct regulatory genetic-toxicology testing. International working groups include: International Workshop for Genotoxicity Testing (IWGT), the Organization for Economic Cooperation and Development (OECD), and the Health and Environmental Sciences Institute (HESI). Division scientists will continue to be involved in discussions concerning the appropriate strategies for conducting risk-assessments of regulated products.
2018 Select Accomplishments
Minimally Invasive Gene-Mutation Assay Identify Mutagens and Carcinogens
Division scientists developed a novel version of the Pig-a assay for rat bone-marrow erythroid cells. These cells are the direct precursors of red blood cells found in circulating blood that are routinely used for the Pig-a assay. Mammalian erythrocytes lack genomic DNA; therefore, confirmation of mutation induction — a necessary step for assay validation — is not possible in erythrocytes. The data from an NCTR study conclusively demonstrated that the Pig-a mutant erythrocytes (red blood cells) measured in the circulating blood of mutagenized rats were descendent from cells containing Pig-a mutations. Bone marrow erythroid precursor cells have nuclei and DNA, and thus are suitable for sequencing Pig-a mutations. Two publications resulted from this research and can be found in the October 2018 issue of Environmental Molecular Mutagenesis.
Detection of Rare Genomic Mutations Using Next-Generation Sequencing (NGS)
FDA scientists from NCTR and the Center for Drug Evaluation and Research are developing a sensitive method to detect mutations induced by chemicals. Mutations are changes in the DNA sequence of an organism, ranging from small point mutations to large chromosome alterations that can cause adverse health effects, such as cancer and genetic disease. The goal of the ongoing study is to establish a new NGS assay that may become a powerful, rapid, and practical tool to routinely evaluate the mutagenicity of FDA-regulated products. Data from this study were interpreted and reported in the December 2018 issue of Archives of Toxicology.
Lung Tumor Model Improves Understanding of Cancer-Drug Resistance
Division scientists detected the outgrowth and enrichment of mutant tumor cells clinically associated with the development of drug resistance. They cultured primary lung tumor organoids—tiny, self-organized three-dimensional tissue cultures—in the presence of varying concentrations of erlotinib (Tarceva®), a drug used to treat lung cancer. Using this novel model and a sensitive method for mutation detection (ACB-PCR) they detected increases in mutant tumor cells after culture. Better patient outcomes are being achieved using personalized cancer treatments by selecting therapies based on tumor genetics. Unfortunately, resistance to the therapy occurs frequently and limits drug efficacy. Because this lung tumor-organoid model reproduces the cellular and mutational diversity of human lung adenocarcinomas, it has the potential to identify treatment strategies and drug combinations that reduce or eliminate drug resistance.
2019 Select Research Projects
- Immunotoxicity Assessment of Nanomaterials Using Human Immune Cell-Based Biomarkers of Innate Immunity
- Somatic Oncomutations as Biomarkers for Translating Preclinical Safety Data to Human Cancer Risk
- Validating the Rat Pig-A Assay for Regulatory Use: Determining the Molecular Basis of Mutants Detected in the Rat Pig-A Gene Mutation Assay
- Developing an In Vitro System to Evaluate the Disease-Related Toxic Effects of Inhaled Test Agents in Human Airway Tissue Models
- Evaluating the Toxicity and Inflammation Produced By Cigarette Smoke Using Human In Vitro Airway Models
- Developing FDA ddPCR Expertise, Training Opportunities, and the Means to Validate Low-Frequency Oncomutation Measurements
- Advance Safety Assessments of FDA-Regulated Products Using High-Throughput and High-Content Quantitative Approaches in Cultured Human Cells to Evaluate Genotoxicity
- Using Metabolically Competent Human Cell Lines to Perform High-Throughput Genotoxicity Testing
- Detection of Rare Genomic Mutations Induced by Genotoxic Carcinogens Using Next Generation Sequencing
- Quantification of In Vivo Genomic Damage by Whole Genome Clone Analysis and High-Fidelity Next Generation Sequencing
Resources For You
- National Center for Toxicological Research
Food and Drug Administration
3900 NCTR Rd
Jefferson, AR 72079
- (870) 543-7391