The miseries of allergies just may help prevent some cancers, s...( There may be a silver -- and healthy...),Health

There may be a silver -- and healthy -- lining to the miserable cloud of allergy symptoms: Sneezing, coughing, tearing and itching just may help prevent cancer -- particularly colon, skin, bladder, mouth, throat, uterus and cervix, lung and gastrointestinal tract cancer, according to a new Cornell study.

These cancers, interestingly, involve organs that "interface directly with the external environment," said Paul Sherman, Cornell professor of neurobiology and behavior, who led the study. He and colleagues analyzed 646 studies on allergies and cancers published over the past 50 years, putting together "the most comprehensive database yet available" on allergies and cancers.

The study revealed "a strong relationship" between allergies and cancer in environmentally exposed tissues, Sherman said. This relationship seldom exists, he noted, between allergies and cancers of tissues that are not directly exposed to the environment, such as cancers of the breast and prostate, as well as myelocytic leukemia and myeloma.

Moreover, the study found that allergies linked to tissues that are exposed to environmental factors -- eczema, hives, hay fever, and animal and food allergies -- were most strongly associated with lower rates of cancers in exposed tissues.

The study, co-authored with Erica Holland '05 (now a medical student at the University of Massachusetts) and Janet Shellman Sherman, a Cornell research scientist and lecturer in neurobiology and behavior, is published in the December issue of The Quarterly Review of Biology (83:4).

"One of our main results was that more than twice as many studies reported inverse allergy-cancer associations as reported positive associations," said Sherman.

Sherman believes that allergy symptoms may help protect against cancer by shedding foreign particles from the body. Some of those particles, he said, might be carcinogenic or carry carcinogens.

"The idea is that t
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