Allergic Disease and Allergy Medications in the Regulation of Breast Cancer

This study aims to better understand the link between allergic disease and cancer, particularly breast cancer. In several studies aimed at examining disease associations, allergy has been associated with a reduced cancer risk. A cell type, known as the mast cell that is activated during allergy, is found in increased numbers around breast tumors. Studies of breast cancer cells have demonstrated that they have receptors for substances, such as histamine, produced by mast cells during allergic reactions. We are investigating two potential explanations for reduced cancer risk in allergy. First that, allergic reactions lead to the production, by mast cells, of substances that will inhibit tumor growth. Second, that commonly used allergy medications such as antihistamines can inhibit breast cancer growth.

We do not yet know which types of cancer patients this will help. However, we do know that during allergic responses, the immune response is enhanced. We also know that mast cells are not destroyed during cancer radiation therapy although other types of immune system cells are badly affected. If mast cell activation in allergy helps to prevent tumor growth, it could lead to the development of new treatments. However, if it is harmful, we should go to greater efforts to use drugs that prevent mast cell activation. Based on current information, the use of common allergy medications may be potentially helpful or harmful in breast cancer. Drugs, such as antihistamines, are very commonly used. It is extremely important to begin to examine the impact of allergy and allergy treatments, so that breast cancer patients and those at high risk of developing disease can be provided appropriate advice. New treatments based on this research may take many years to develop. However, improved advice on the potential impact of allergy medications and allergic disease on breast cancer could be available as a result of this study within a much shorter time frame and inform both current treatment and the development of improved studies in this area.