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Numerous studies have demonstrated an inverse relationship between dietary flavonoid intake and cancer risk,which 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 (accounting for NQO1 genotype),using data from the LACE and NCCLS studies,respectively.High daidzein (soy) consumption after a breast cancer diagnosis was associated with a reduced risk of recurrence in postmenopausal women treated with tamoxifen.A significantly reduced risk of childhood leukemia was associated with mothers who consumed the most flavonoids during pregnancy.Carrying the NQO1 2 variant allele was not independently associated with the risk of childhood ALL or AML and there was no significant interaction with flavonoid intake.In a meta-analysis,NQO1 2 had no significant effect on risk of childhood leukemia overall but was associated with an increased risk in a subset of leukemia cases with MLL translocations. These results suggest that high flavonoid intake may be associated with a reduced risk of breast cancer and childhood leukemia.

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Neela Guha holds a B.A. in Molecular and Cell Biology, M.P.H. in Epidemiology and Biostatistics and Ph.D. in Epidemiology from the University of California at Berkeley. She is currently employed as a scientist with the International Agency for Research on Cancer, World Health Organization.

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