Background: Several studies in epidemiology indicate that risk of pancreatic cancer is reduced in individuals with allergies. Although genes have been identified that are critical in allergic response, polymorphisms in these genes have not been studied in relation to risk of pancreatic cancer. We hypothesized that variants in these genes are related to risk.
Methods: We investigated the association of allergies and pancreatic cancer in a hospital-based case-control study with 405 cases and 212 controls. In a subgroup of 149 cases and 135 controls, we studied the association of variants in IL-4 (C-589T, G3017T) and IL-4R alpha (Gln576Arg) with allergies and with risk of pancreatic cancer.
Results: We found reduced risk of pancreatic cancer associated with allergies, with adjusted odds ratios of 0.58 (95% CI 0.40-0.84) for any allergies, 0.45 (95% CI 0.29-0.70) for hay fever, and 0.43 (95% CI 0.23-0.80) for animals. The minor allele at each locus studied was associated with reduced risk of allergies in controls, leading us to hypothesize that they would be associated with increased risk of pancreatic cancer. Overall, there was no association between the genotypes studied and risk of pancreatic cancer. In analyses within strata defined by presence or absence of allergies, there were differences in risk associated with genotype for IL-4 G3017T: there was slightly increased risk among those with allergies and reduced risk among those without allergies.
Conclusions: The consistent association of allergies with risk of pancreatic cancer and these results suggest that associations between variants in genes related to allergic response and pancreatic cancer warrant further study.