Soy products in the management of breast cancer.
OBJECTIVE
Meta-analyses of epidemiological studies of soy consumption and breast cancer risk have demonstrated modest protective effects, usually attributed to isoflavones. Concern has been expressed, however, that the estrogenic activity of isoflavones may have adverse effects on breast cancer recurrence.


RESULTS
The review covers epidemiological studies that have investigated the impact of soy consumption in breast cancer patients on recurrence and mortality. There are preliminary data to suggest that soy has differential effects on recurrence in human epidermal growth factor receptor-2 positive and human epidermal growth factor receptor-2 negative tumours. Recent studies on mechanisms of action of soy in breast cancer provide insights into epigenetic effects and the interaction of isoflavones with IGF-1 and with a number of polymorphisms of genes associated with breast cancer risk such as MDM2 and CYP1B1.


CONCLUSIONS
Overall, these studies indicate that soy foods consumed at levels comparable to those in Asian populations have no detrimental effects on risk of breast cancer recurrence and in some cases significantly reduce the risk. Importantly, soy does not appear to interfere with tamoxifen or anastrozole therapy. Recent research suggests that women who are at increased risk of breast cancer due to polymorphisms in genes associated with the disease may especially benefit from high soy isoflavone intake.
Northern Ireland Centre for Food and Health, School of Biomedical Sciences, University of Ulster, Coleraine, UK.
Pamela J
PJ
Magee
Ian
I
Rowland
D000077384:Anastrozole; D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics / Q000378:metabolism; D044466:Asian People; D001943:Breast Neoplasms / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics / Q000517:prevention & control*; D065633:Cytochrome P-450 CYP1B1; D004032:Diet / Q000009:adverse effects; D004347:Drug Interactions; D005260:Female; D006801:Humans; D015994:Incidence; D007529:Isoflavones / Q000009:adverse effects / Q000494:pharmacology*; D015201:Meta-Analysis as Topic; D009570:Nitriles / Q000494:pharmacology; D011110:Polymorphism, Genetic; D011379:Prognosis; D051736:Proto-Oncogene Proteins c-mdm2 / Q000235:genetics / Q000378:metabolism; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics / Q000378:metabolism; D012008:Recurrence; D012307:Risk Factors; D045730:Soy Foods / Q000009:adverse effects; D013629:Tamoxifen / Q000494:pharmacology; D014230:Triazoles / Q000494:pharmacology
D000077384:Anastrozole; D001189:Aryl Hydrocarbon Hydroxylases; D065633:Cytochrome P-450 CYP1B1; D007529:Isoflavones; D009570:Nitriles; D051736:Proto-Oncogene Proteins c-mdm2; D018719:Erb-b2 Receptor Tyrosine Kinases; D013629:Tamoxifen; D014230:Triazoles; C585496:CYP1B1 protein, human; C497206:MDM2 protein, human; C508053:ERBB2 protein, human