Asthma and allergies may reduce risk

USA Today (Society for the Advancement of Education), Oct, 2005

Having asthma, hay fever, or another allergic condition may reduce the risk of developing one fatal form of brain cancer, suggests a study from Ohio State University, Columbus. New evidence for this relationship is found in the normal variation of two genes.

"Variations in certain genes may make a person more prone to develop asthma or allergies and those same variations may protect adults against the most common kind of brain cancer," says Judith Schwartzbaum, associate professor of public health.

Glioblastoma multiforme (GBM) affects three out of 100,000 people, a rate that quadruples among those who are 65 and older. The average five-year survival rate from the time of diagnosis is 3.3%.

The current study supports several years' worth of research by other scientists who have suggested an inverse relationship between asthma, allergies, and GBM. Those studies, however, were based only on information that participants gave about their history of asthma and allergies, not on data from DNA testing.

"We needed an objective way to measure the accuracy of allergy self reports, one that isn't affected by the presence of a brain tumor," Schwartzbaum notes. "Looking at genetic variation is one way to do this."

That genetic variant is called a polymorphism. While a mutation has a rare and abnormal DNA pattern, a polymorphism consists of common patterns, each considered normal. Polymorphisms can offer protection against certain diseases or render a person more vulnerable to particular conditions. For example, researchers suspect that several polymorphic forms of key genes may increase susceptibility to Alzheimer's disease.

The researchers looked for polymorphisms on two genes associated with asthma and allergies, IL-4RA and IL-13. "People who have polymorphisms in the two genes that we examined may be susceptible to allergic conditions and may also have a lower risk of GBM," Schwartzbaum concludes.