Chemopreventive dietary compounds, such as
flavonols, may inhibit colorectal
carcinogenesis partly by altering
cytokine expression and attenuating
inflammation. Single nucleotide polymorphisms (SNPs) in the promoter regions of genes encoding
cytokines may influence
flavonol-induced changes in
cytokine expression and consequently
cancer risk. Using logistic regression, we estimated odds ratios (OR) and 95% confidence intervals (CI) for the association between SNPs of
interleukin (IL)-1β, 6, 8, and 10 alone or combined with
flavonol intake or serum IL concentration changes, and
adenoma recurrence in 808 participants from the intervention arm of the
Polyp Prevention Trial, a 4-year intervention study evaluating the effectiveness of a low-fat, high-fiber, high-fruit and vegetable diet on
adenoma recurrence. Overall, SNPs in genes encoding IL-1β, 6, 8, and 10 were not associated with their corresponding serum concentrations or
adenoma recurrence. However, individuals homozygous for
IL-10 -592 C (OR=2.23, 95% CI: 1.07-4.66, P(interaction)=0.03) orIL-10 -819 C (OR=2.18, 95% CI: 1.05-4.51, P(interaction)=0.05) had an elevated risk of high-risk
adenoma recurrence when their serum
IL-10 concentrations increased during the trial. In addition,
IL-6 -174 GG in combination with above median
flavonol intake (OR=0.14, 95% CI: 0.03-0.66) or with decreased
IL-6 concentrations (OR=0.14, 95% CI: 0.03-0.65) reduced the risk of advanced
adenoma recurrence, although the interaction term was not statistically significant. In conclusion, our results suggest that IL SNPs, in combination with a
flavonol-rich diet or decreased serum IL, may lower the risk of
adenoma recurrence.