Epidemiological associations of allergy, IgE and cancer

Abstract

Several epidemiological studies have evaluated potential associations between allergy and risk of malignancy. It remains clear that the relationship between allergy and cancer is complex. Three hypotheses have been proposed to account for observed relationships: these are chronic inflammation, immunosurveillance, prophylaxis, and we propose adding a fourth: inappropriate T-helper 2 (Th2) immune skewing. Each of these attempts to explain either the increased or decreased risk of different cancer types in 'allergic' patients reported in the literature. All four hypotheses are based on known mechanisms of allergic inflammation and/or IgE antibody functions, and uphold the view of an immunological basis for the relationship between allergy and malignancies. This review summarizes and draws conclusions from the epidemiological literature examining the relationships between specific types of cancer and allergic diseases. Particular emphasis is placed on the most recent contributions to the field, and on consideration of the allergic immune mechanisms that may influence positive or negative associations.

The link between neoplastic and atopic diseases

“…Reduced levels of IgE and histamine have been found in patients with neoplastic diseases. IL-12 is an anti-allergic inflammation cytokine that stimulates T cells and NK cells as well as the production of INF gamma, which stimulates macrophages to kill neoplastic cells [3,4]. Perhaps these described reactions explain the lower incidence of chronic leukemia in atopy patients.…”

“…Damage to the oxidative pathways of cells induces the mutation of suppressor genes and posttranslational modifications of proteins responsible for DNA repair processes or apoptosis process control. The transition in the Th1/Th2 balance towards Th2 lymphocytes among allergy patients fosters inhibition of correct production processes of cytotoxic effector cells and simultaneously lowers their ability to eliminate neoplastic cells [3,4]. What these two theories have in common is the field of "allergo-oncology", which analyzes the correlation between the immunological system and the occurrence of neoplastic diseases [5].…”

Cutting Edge: IgE Plays an Active Role in Tumor Immunosurveillance in Mice

“…The strength of the IgE response may therefore be an evolutionary compromise, finetuned to convey antiparasitic and tumor surveillance activity. Slight deviations from the optimal IgE response may explain the high incidence of atopy, which, interestingly, does seem to correlate with a lowered risk for developing cancer (9,26,27).…”

Understanding the Role of the Immune System in the Development of Cancer: New Opportunities for Population-Based Research

“…Epidemiologic studies with measures on lifetime history to allergies, or other chronic inflammatory conditions, such as periodontal disease, provide data on immune dysregulation and their associations with cancer risk. A growing number of studies have observed inverse associations between allergies and risk of brain, pancreatic, colorectal, hematologic, and gynecologic malignancies (23)(24)(25); in contrast, a history of allergies appears to be positively associated with lung and urological malignancies (25). The potential mechanisms have been reviewed and include chronic inflammation, immunosurveillance, inappropriate Th2 immune skewing, and prophylaxis (25).…”