Leukemia begins in chromosomes, the microscopic rod-shaped bodies that carry genes, Caligiuri said. The genes determine whether a person has brown or blue eyes, blond or red hair, and hundreds of other characteristics. At times, chromosomes break and join with other broken chromosome parts, causing the genes within them to fuse. There are millions of possible gene fusions, but a couple of dozen combinations can lead to leukemia. Chemicals can cause leukemia by encouraging chromosomes to break.
More frequent breaks increase the odds of dangerous gene fusions.
Researchers know that exposure to some chemicals causes leukemia. They know how it happens and have identified specific genetic mutations that lead to the development of the disease, Caligiuri said. But other pollutants also are believed to damage chromosomes, which can lead to genetic mutations. Pesticides, hair dyes, solvents and glues are among the suspects, Caligiuri said. Other scientists have identified X-rays, asbestos and caffeine as possible causes of chromosome breaks.