Allergies, Asthma May Protect Against Brain Cancer
Study Shows a Genetic Link Between the 2
Another possibility, she says, is that the immune response that is triggered in people with asthma and allergies helps protect them against the brain cancer. This is just speculation, but Schwartzbaum says the implications of such an association would be great.
"If this is the case the question becomes, 'How aggressively should you treat these conditions?'" she tells WebMD. "Obviously, people can die from asthma. It is a serious disease that needs to be treated. But it could be that a little bit of hay fever may be a good thing."
So how could the same genetic variants promote one disease while protecting against another? Inflammation may hold the key, Schwartzbaum says. It turns out that the same cytokines that cause allergy- and asthma-promoting inflammation in the lungs inhibit inflammation in the brain. Less inflammation may mean less cancer risk.
NCI researcher Peter Inskip, ScD, was a co-researcher of the agency's 2002 allergy and brain cancer study. He tells WebMD that the link has now been seen in multiple studies, "which lessens the likelihood that it is due to chance or bias."
"We cannot rule out the possibility that allergies or asthma are directly protective," he says. "However, other possibilities should be considered. A possible protective role of medication taken for allergies and/or asthma needs to be evaluated further."
The NCI is continuing its research on allergies, asthma, and glioblastomas, he says.
"We know very little about the etiology of brain cancers, most of which are gliomas," he says. "The findings concerning allergies/asthma that have emerged over the last few years provide one of the most promising leads that we have. It is extremely important that researchers pursue this lead in order to better understand the biological basis of the association."