Asthma may reduce the risk of brain tumors -- but how

Asthma has been associated with a lowered risk of brain tumors, and researchers at Washington University School of Medicine in St. Louis now think they know why: Immune cells activated under conditions of asthma are less able to promote the growth of brain tumors. The findings could lead to new therapeutic approaches.
There’s not much good that can be said about asthma, a breathing disease in which the airways become narrowed and inflamed. But there’s this: People with asthma seem to be less likely to develop brain tumors than others.