Annoying allergies may actually offer defense against cancer
Washington, Oct 30 ANI:
Allergies are much more than just an annoying immune malfunction, they may protect against certain types of
cancer, suggests a new study.According to a new
article in the December issue of The Quarterly
Review of
Biology,
allergy symptoms may protect against cancer by expelling foreign particles, some of which may be carcinogenic or carry absorbed carcinogens, from the organs most likely to come in with contact them.In addition, allergies may serve as early warning devices that let
people know when there are substances in the air that should be avoided.The article has been produced by researchers Paul Sherman, Erica Holland and Janet Shellman Sherman from Cornell
University.
Medical researchers have long suspected an
association between allergies and cancer, but extensive study on the subject has yielded mixed, and often contradictory, results. Many studies have found inverse associations between the two, meaning cancer
patients tended to have fewer allergies in their medical
history. Other studies have found positive associations, and still others found no association at all.In an attempt to explain these contradictions, the Cornell team reexamined nearly 650 previous studies from the past five decades. They found that inverse allergy-cancer associations are far more common with cancers of organ systems that come in direct contact with matter from the external
environment-the mouth and throat, colon and rectum, skin, cervix, pancreas and glial
brain cells. Likewise, only allergies associated with tissues that are directly exposed to environmental assaults-eczema, hives, hay fever and
animal and
food allergies-had inverse
relationships to cancers.Such inverse associations were found to be far less likely for cancers of more isolated tissues like the
breast, meningeal brain cells and
prostate, as well as for myeloma, non-Hodgkins lymphoma and myelocytic leukemia.The
relationship between
asthma and
lung cancer, however, is a special case. A majority of the studies that the Cornell team examined found that asthma correlates to higher rates of
lung cancer. "Essentially, asthma obstructs clearance of pulmonary mucous, blocking any potentially prophylactic benefit of allergic expulsion," they explain. y contrast, allergies that affect the
lungs other than asthma seem to retain the protective effect. So if allergies are part of the body's defense against foreign particle invaders, is it wise to turn them off with antihistamines and other suppressants The Cornell team says that studies specifically designed to answer this question are needed. ANI
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