Dietary flavonoids and the risk of breast cancer and childhood leukemia.

摘要

Numerous studies have demonstrated an inverse relationship between dietary flavonoid intake and cancer risk. This association may be modified by polymorphisms in flavonoid metabolizing genes, such as NQO1. The independent role of dietary flavonoids was explored in breast cancer and childhood leukemia. The main effect of NQOI*2 and the joint effect with flavonoid intake was assessed in childhood leukemia. Multivariable Cox proportional hazards regression and unconditional logistic regression models were used to analyze data from the Life After Cancer Epidemiology Study (LACE) and the Northern California Childhood Leukemia Study (NCCLS), respectively.;Consuming more than 9 6 mg daidzein isoflavones daily from soy foods after a breast cancer diagnosis was associated with a non-significantly reduced risk of recurrence in women who were postmenopausal (Hazard Ratio [HR], 0.70; 95% confidence interval [CI], 0.27-1.77) or had ever used tamoxifen (HR, 0.48; 95%CI, 0.19-1.21) in the LACE study. Among postmenopausal women ever treated with tamoxifen, there was a significant reduction in breast cancer recurrence comparing the highest (> 1.5 mg/day) to the lowest ( 7.7 mug/day) daidzein intake (HR, 0.48; 95%CI, 0.21-0.79).;A meta-analysis demonstrated that overall the NQO1*2 variant allele had no significant effect on risk of childhood leukemia. There was, however, an increased risk associated with having at least one copy of NQO1*2 in a subset of all leukemia cases with MLL translocations (summary odds ratio [OR], 1.39; 95% CI, 0.98-1.97).;In the NCCLS data, there was a significantly reduced risk of childhood leukemia associated with mothers consuming 9.6-20 mg quercetin daily during pregnancy (OR for non-Hispanic white children with ALL, 0.25; 95% CI, 0.10-0.61; OR for cases harboring a prenatal translocation other than MLL, 0.22; 95% CI, 0.07-0.70). Having at least 1 copy of the NQO1*2 allele was not independently associated with the risk of childhood ALL or AML (p-value for linear trend > 0.05) and, although tenuous because of sample size, there was no significant interaction between quercetin and the NQO1*2 allele.