An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

Research Grants

NIEHS/EPA CEHCs: Center for Integrative Research on Childhood Leukemia and the Environment (CIRCLE) - UC Berkeley


Leukemia, or cancer of the white blood cells, is the most common type of childhood cancer. Scientists at this center are examining how early exposure to toxic chemicals might contribute to leukemia in children.

Research at this center focuses on the effects of pesticides, tobacco-related contaminants, polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs, or brominated flame retardants) in the womb and early in life. To determine if and how, early exposure to such chemicals might cause childhood leukemia, scientists are trying to identify which chemicals are associated with a higher risk for leukemia and are looking at how these chemicals interact with genes known to be involved in leukemia development.

Researchers at this children’s center are evaluating environmental exposures in the womb and in early childhood, using existing home dust samples and biospecimens from the Northern California Childhood Leukemia Study. They are also examining environmental and genetic influences for distinct leukemia subtypes and sharing their findings with other researchers and the public to help prevent childhood leukemia and improve children's health.

  • Research Projects

    Project 1: Childhood Leukemia International Consortium Studies
    The chemicals that children are exposed to can have a dramatic impact on their health and the interaction between various chemicals they are exposed to can change that reaction in many ways. Some studies have linked tobacco smoke and pesticides applied in homes with childhood leukemia; however, most of these studies are limited by small sample sizes. This project pools data from 14 case-control studies in 10 countries within the Childhood Leukemia International Consortium (CLIC) to provide a more definitive assessment of the contribution of environmental chemicals to childhood leukemia. The researchers are examining linkages between parental smoking and home pesticide use, genetic variations that make children more or less likely to be able to process foreign chemicals and the risks of different types of childhood leukemia in different populations.

    Project Leader: Catherine Metayer, Ph.D., University of California, Berkeley

    Project 2: Exposure Assessment for Childhood Leukemia
    This project aims to improve scientists’ ability to assess whether – and when – children have been exposed to environmental chemicals and to identify which chemicals raise the risk for childhood leukemia.  The study builds on data from the Northern California Childhood Leukemia Study using blood samples from 250 childhood leukemia patients. The researchers are looking to see if there is an association between levels of nicotine, PAHs (polycyclic aromatic hydrocarbons from combustion), PCBs (polychlorinated biphenyls), and PBDEs (polybrominated diphenyl ethers – flame retardants) in the blood and measurements of chemicals in house dust. Using methods newly developed by UC Berkeley, investigators analyze newborn dried blood spots (DBS) collected at birth to quantify internal doses of chemical exposures.

    Project Leader: Stephen M. Rappaport, Ph.D., University of California, Berkeley

    Project 3: Prenatal Exposures, DNA Methylation, and Childhood Leukemia
    Once researchers identify a link between a chemical exposure and childhood leukemia, the next step is to find out how the chemical causes cancer. The cause often involves changes in a person’s genetic code or the activation or repression of certain genes. This project examines how certain toxins affect a person’s cells at the molecular level to help advance methods for early detection of leukemia diagnosis using newborn DBS from the general population.

    Project Leader: Joseph L. Wiemels, Ph.D., University of California, San Francisco

  • Outcomes

    Primary Environmental Exposures: Pesticides, tobacco-related contaminants, PCBs, PBDEs
    Primary Health Outcomes: Childhood leukemia