title: Effect of dietary intake of phytoestrogens on estrogen receptor status in premenopausal women with breast cancer.
abstract: Although many dietary studies have focused on breast cancer risk, few have examined dietary influence on tumor characteristics such as estrogen receptor (ER) status. Because phytoestrogens may modulate hormone levels and ER expression, we analyzed ER status and phytoestrogen intake in a case-case study of 124 premenopausal breast cancer patients. We assessed intake with a food-frequency questionnaire and obtained ER status from medical records. Rather than focusing on risk, we evaluated whether low intakes were more strongly associated with ER-negative tumors than with ER-positive disease. In logistic regression adjusting for potential confounders, threefold greater risks of ER-negative tumors relative to ER-positive tumors were associated with low intake of the isoflavones genistein (odds ratio, OR=3.50; 95% confidence interval, CI=1.43-8.58) and daidzein (OR=3.10; 95% CI=1.31-7.30). Low intake of the flavonoid kaempferol (OR=0.36; 95% CI=0.16-0.83), the trace element boron (OR=0.33; 95% CI=0.13-0.83), and the phytosterol beta-sitosterol (OR=0.42; 95% CI=0.18-0.98) were associated with decreased risk of ER-negative tumors relative to ER-positive disease. Other phytoestrogens were not significantly associated with ER status. Thus, in premenopausal patients, some phytoestrogens may affect breast carcinogenesis by influencing ER status. Such findings suggest new directions for mechanistic research on dietary factors in breast carcinogenesis that may have relevance for prevention and clinical treatment.
authors.affiliation: Department of Epidemiology, The University of Texas M.D. Anderson Cancer Center, Houston 77030, USA.
authors.forename: Marina S
authors.initials: MS
authors.lastname: Touillaud
authors.forename: Patricia C
authors.initials: PC
authors.lastname: Pillow
authors.forename: Jelena
authors.initials: J
authors.lastname: Jakovljevic
authors.forename: Melissa L
authors.initials: ML
authors.lastname: Bondy
authors.forename: S Eva
authors.initials: SE
authors.lastname: Singletary
authors.forename: Donghui
authors.initials: D
authors.lastname: Li
authors.forename: Shine
authors.initials: S
authors.lastname: Chang
mesh_terms: D000328:Adult; D016588:Anticarcinogenic Agents / Q000008:administration & dosage / Q000494:pharmacology; D001895:Boron / Q000008:administration & dosage / Q000494:pharmacology; D001943:Breast Neoplasms / Q000178:diet therapy / Q000378:metabolism*; D004032:Diet; D005260:Female; D019833:Genistein / Q000494:pharmacology; D006801:Humans; D000960:Hypolipidemic Agents / Q000008:administration & dosage / Q000494:pharmacology; D007529:Isoflavones / Q000008:administration & dosage / Q000494:pharmacology; D044949:Kaempferols / Q000008:administration & dosage / Q000494:pharmacology; D008875:Middle Aged; D009752:Nutritional Status / Q000502:physiology*; D016017:Odds Ratio; D048789:Phytoestrogens / Q000008:administration & dosage / Q000494:pharmacology*; D017697:Premenopause / Q000502:physiology*; D011960:Receptors, Estrogen / Q000187:drug effects* / Q000378:metabolism; D012307:Risk Factors; D012855:Sitosterols / Q000008:administration & dosage / Q000494:pharmacology; D011795:Surveys and Questionnaires
chemical_list: D016588:Anticarcinogenic Agents; D000960:Hypolipidemic Agents; D007529:Isoflavones; D044949:Kaempferols; D048789:Phytoestrogens; D011960:Receptors, Estrogen; D012855:Sitosterols; C025473:gamma-sitosterol; C004742:daidzein; C006552:kaempferol; D019833:Genistein; D001895:Boron