Superfund Research Program
Biomarkers of Chemical Exposure and Leukemia Risk
Final Progress Reports
Year: 2010 2005
Childhood leukemia is the most common form of childhood cancer, affecting 3,000 children annually in the U.S. and many more worldwide. The causes are essentially unknown. The major form of childhood leukemia is ALL (acute lymphoblastic leukemia), and the other is AML (acute myeloid leukemia).
The goal of this project is to determine the role chemical exposures play in the development of childhood leukemia. In one of the largest studies of its kind in the world, bone marrow and/or peripheral blood was obtained on 961 cases of childhood leukemia, and peripheral blood and urine were obtained from many of the mothers. These have been analyzed with the latest technologies.
Important discoveries so far
Project investigators examined whether the use of paint and petroleum solvents at home before birth and in early childhood influenced the risk of leukemia in children. They found that ALL risk was significantly associated with paint exposure, with a higher risk observed when paint was used post-natally, by an adult other than the mother, or frequently. They found no significant association between solvent use and ALL risk overall, but a significant association with AML risk was observed.
The investigators measured blood levels of selected Superfund chemicals in the blood of mothers of children with leukemia and control mothers, including 33 volatile organic compounds (VOCs), and urine levels for 10 cancer-causing polycyclic aromatic hydrocarbons (PAHs) and cotinine (a biomarker of smoking). House dust was collected simultaneously and a significant positive correlation between levels of nicotine in house dust and those of serum cotinine (a nicotine metabolite) in maternal blood samples was found, showing that nicotine in house dust is a good surrogate marker of adult smoking in the home. House dust was also used as an exposure indicator to examine the risk of childhood leukemia in relation to residential exposure to persistent organochlorine chemicals, such as polychlorinated biphenyls (PCBs). Detection of any PCB congener in the dust conferred a 2-fold increased risk of ALL.
Earlier studies had shown that most causal genetic changes found in the children’s leukemia were present before they were born. Recent studies have shown that secondary changes, including those in a cancer gene called RAS, occur postnatally after the child is born.
What they plan to do next
The project has now become part of a new NIEHS/EPA Children’s Environmental Health Center called the Center for Interdisciplinary Research on Childhood Leukemia and the Environment (CIRCLE), led by Dr. Buffler.