The current Scandinavian prospective study was designed to investigate the associations between vitamin C, vitamin E, folate, and β-carotene intake from diet and supplements and the risk of postmenopausal breast cancer. Few studies on micronutrients and breast cancer have examined the associations with the histology (ductal/lobular) and hormone receptor status of the tumors. The study included 26,224 postmenopausal women who provided information concerning diet, supplements and lifestyle through questionnaires. During follow-up, 1,072 cases of breast cancer were diagnosed among the study participants. Cox proportional hazard analyses were used to calculate incidence rate ratios (IRRs) of breast cancer overall and breast cancer subtypes related to micronutrient intake. No associations were found between overall risk of breast cancer and any of the micronutrients studied. However, some effects were found when the results were stratified by breast cancer subtypes. Dietary (but not supplemental) beta-carotene was found to have a protective effect against lobular breast cancer (IRR = 0.72, 95% confidence interval (CI) = 0.57-0.91). Dietary vitamin E was associated with lower risk of estrogen receptor positive (ER+) and progesterone positive (PR+) breast cancer (IRR = 0.50, 95% CI = 0.25-0.98). On the other hand, dietary folate was found to be associated with higher risk of ER+/PR+ breast cancer (IRR = 1.27, 95% CI = 1.03-1.95). The authors conclude that no effect of micronutrients was found on overall risk of postmenopausal breast cancer. However, the results indicated possible effects of micronutrients in subgroups of breast cancer, with a potential beneficial effect of dietary beta-carotene in lobular breast cancer and dietary vitamin E in ER+/PR+ breast cancer and a potential harmful effect of dietary folate in ER+/PR+ breast cancer.

The current prospective study was designed to investigate the association between breast cancer recurrence and vegetable intake, with a focus on the impact on those using tamoxifen. The protective effect of vegetables on the risk of breast cancer recurrence has not been established. Previous reports of anti-carcinogenic activity of phytochemicals in cruciferous vegetables in combination with tamoxifen led the authors to include specific evaluation of this class of vegetables in the study. The study included 3,080 breast cancer survivors enrolled in the Women's Healthy Eating and Living (WHEL) Study. Vegetable intake based on repeat 24-hour dietary recalls were examined as a secondary analysis in the cohort. The women were 23.5 months post-diagnosis, on average, at time of enrollment. The hazard of recurrence with vegetable intake was assessed in the overall study group and separately for women taking tamoxifen, while controlling for relevant clinical and demographic variables. Participants reported baseline average intakes of 3.1 +/- 0.05 servings per day of vegetables, and 0.5 +/- 0.02 servings per day of cruciferous vegetables. Vegetable intake was divided into thirds. Vegetable intake in the highest compared to the lowest thirds was found to be associated with a lower adjusted hazard ratio (HR) for breast cancer recurrence of 0.69 (95% confidence interval (CI) = 0.55-0.87). Among women taking tamoxifen, HR = 0.56 (95% CI = 0.41-0.77) for total vegetable intake and HR = 0.65 (95% CI = 0.47-0.89) for cruciferous vegetable intake. For women using tamoxifen who had above median cruciferous vegetable intake, as well as being within the highest third of total vegetable intake, HR = 0.48 (95% CI = 0.32-0.70). The authors conclude that baseline vegetable intake may be associated with a reduction in the risk of breast cancer recurrence or new events, particularly for those using tamoxifen. The associations deserve further study since it is possible that vegetable intake is simply a surrogate for other health-promoting behaviors.

The present study was designed to investigate the mechanism by which the cruciferous vegetable compound benzyl isothiocyanate suppresses the viability of human breast cancer cells. Benzyl isothiocyanate has been shown to inhibit the growth of both hormone receptor positive MCF-7 and hormone receptor negative MDA-MB-231 human breast cancer cells and also to retard mammary cancer development in MMTV-neu mice by causing apoptosis. However, but the mechanism of cell death is not fully understood. The authors show that whereas p53 is not required for benzyl isothiocyanate-induced cell death, proapoptotic response to benzyl isothiocyanate is mediated by suppression of X-linked inhibitor of apoptosis (XIAP) protein expression. Benzyl isothiocyanate treatment heightened levels of total and Ser15-phosphorylated p53 protein in MCF-7 breast cancer cells, but the proapoptotic response to benzyl isothiocyanate remained even after knockdown of the p53 protein level. In both MCF-7 and MDA-MB-231 cells, exposure to benzyl isothiocyanate caused in a marked decrease in protein level of XIAP as soon as eight hours after treatment. Ectopic expression of XIAP was found to confer statistically significant protection against benzyl isothiocyanate-mediated cytoplasmic histone-associated apoptotic DNA fragmentation in both breast cancer cell types. In addition, inhibition of implanted MDA-MB-231 cell growth in female athymic mice by benzyl isothiocyanate administration was related to a modest but statistically significant decrease in XIAP protein level. The benzyl isothiocyanate treatment also was found to cause induction as well as nuclear translocation of survivin only in the MCF-7 cells. Furthermore, the benzyl isothiocyanate-induced apoptosis was modestly but statistically significantly augmented by RNA interference of survivin in MCF-7 breast cancer cells. The authors comment that their study provides new insight into the molecular mechanism of benzyl isothiocyanate-induced apoptosis. In particular, suppression of XIAP expression is a critical mediator of this process.

The present prospective study was designed to investigate the associations of caffeinated coffee and black tea consumption with risk of breast cancer overall and by hormone receptor status. The study included 61,433 women in the Swedish Mammography Cohort who were cancer free during the baseline enrollment period of 1987 to 1990. Coffee and tea intake was determined using a food-frequency questionnaire administered both at baseline and in 1997. Swedish cancer registers were accessed to obtain information concerning the incidence and nature of newly diagnosed invasive breast cancers in the study cohort. During an average follow-up period of 17.4 years (through year-end 2007), 2,952 incident cases of invasive breast cancer were found. Coffee consumption was found not to be associated with overall risk of breast cancer (multivariate relative risk (RR) for at least four cups per day compared to less than one cup per day = 1.02; 95% confidence interval (CI) = 0.87 - 1.20). Nor was any association found between coffee consumption and breast cancer subtype defined by estrogen receptor (ER) and progesterone receptor (PR) status. On the other hand, black tea intake was found to be significantly positively associated with risk of breast cancer overall and ER+/PR+ tumors in particular. The multivariate RRs comparing at least two cups of black tea per day with no consumption were 1.22 (95% CI = 1.05 - 1.42) for breast cancer overall and 1.36 (95% CI = 1.09 - 1.69) for ER+/PR+ breast cancer. The authors conclude that the study findings do not support a role of coffee consumption in the development of breast cancer. However, the results suggest that black tea may be positively associated with risk of ER+/PR+ breast cancer.

The present study was designed to investigate the impact of zeranol, an anabolic growth promoter used by the U.S. beef industry to stimulate cattle growth, on human breast cancer cells. The molecular links between obesity and breast cancer have been studied extensively, but the relationship is not fully clear. Obesity has been shown to significantly increase the risk of breast cancer, as well as increasing the likelihood of death from breast cancer. Leptin (a hormone secreted primarily by fat cells) production is enhanced in obesity. Leptin has also been shown to promote breast cancer cell growth. Zeranol is a growth promoter whereas (-)-gossypol, a polyphenol extracted from cottonseed, has been shown to be chemopreventive. In the study, the effects of leptin, zeranol, and (-)-gossypol on the growth of MCF-7 Adr hormone receptor positive (ER+/PR+) human breast cancer cells were investigated. Leptin was found to enhance the sensitivity of MCF-7 Adr cells to zeranol; the combination increased cancer cell growth. The findings suggest that exposure to zeranol may lead to initiation of transformation of normal breast cells to breast precancerous cells. The authors conclude that obese individuals may be at greater risk of developing zeranol-induced breast cancer as a result of their heightened leptin production.

The present study was designed to investigate the influence of the dietary phytoestrogens enterolactone and genistein on breast cancer angiogenic factors. Formation of new blood vessels is an important element of cancer progression and its regulators are released both by the cancer cells and the stroma. Stroma, which is interposed between cancer cells and normal host tissues, is essential for tumor growth. Dietary phytoestrogens, such as the lignan enterolactone and the isoflavone genistein, may influence breast cancer growth differently. In the study, human hormone receptor positive (ER+/PR+) MCF-7 breast cancer cells were transplanted into ovariectomized athymic mice, creating a tumor. The mice were fed one of four diets supplemented with estradiol (E2): (1) control basal AIN-93G diet (basal diet); (2) basal diet supplemented with 100 mg/kg enterolactone; (3) basal diet supplemented with 100 mg/kg genistein; or (4) basal diet supplemented with their combination (enterolactone+genistein). Both the enterolactone and enterolactone+genistein diets were found to inhibit E2-induced cancer growth and angiogenesis while genistein alone did not. Extracellular proteins in mice tumors were sampled using microdialysis. Both enterolactone and enterolactone+genistein were observed to result in a reduction of both stroma- and cancer cell-derived vascular endothelial growth factor (VEGF), whereas cancer cell-derived placenta growth factor (PlGF) was found to increase. Furthermore, enterolactone and enterolactone+genistein reduced E2-induced endothelial cell infiltration while genistein alone did not. Finally, in endothelial cells, E2-induced VEGFR-2 expression was inhibited by enterolactone but not by genistein. The authors conclude that dietary enterolactone has powerful anti-estrogenic effects on breast cancer growth (even in combination with genistein) by down regulating E2-stimulated angiogenic factors derived both from the stroma and the cancer cells while genistein does not posses any anti-estrogenic effects.

The present prospective population study was designed to examine the association between dietary fiber intake and risk of breast cancer by hormone receptor status and histologic type among postmenopausal women. Although it has been postulated that dietary fiber might lower the risk of breast cancer by modulating estrogen metabolism, the association between dietary fiber and breast cancer risk by hormone receptor status is not clear. The study included 185,598 postmenopausal women with average age 52 in the National Institutes of Health–AARP Diet and Health Study. Dietary intakes were determined by a food-frequency questionnaire and new breast cancer cases were identified by means of linkages with state cancer registries. Cox proportional hazard models were used to calculate relative risks (RRs) and two-sided 95% confidence intervals (CIs). During an average follow-up period of seven years, 5,461 breast cancer cases were identified, of which 3,341 had information concerning estrogen receptor (ER) and progesterone receptor (PR) status. Overall consumption of dietary fiber was found to be inversely associated with risk of breast cancer: RR for the highest compared to the lowest quintile of intake = 0.87, 95% CI: 0.77 - 0.98; P for trend: 0.02. The inverse association was stronger for estrogen receptor negative/progesterone receptor negative (ER-/PR-) tumors: RR = 0.56, 95% CI: 0.35 - 0.90; P for trend: 0.008 (366 cases) than for ER+/PR+ tumors: RR = 0.95, 95% CI: 0.76 - 1.20; P for trend: 0.47 (1,641 cases). The relative risk was also significantly lower for lobular tumors: RR = 0.66, 95% CI: 0.44 -0.97; P for trend: 0.04 than for ductal tumors: RR = 0.90, 95% CI: 0.77 - 1.04; P for trend: 0.10. When stratified by type of food, fiber intake from grains, fruit, vegetables, and beans was not found to be related to risk of breast cancer.

The present prospective study was designed to investigate the association between intake of conjugated linoleic acids (CLAs) and the risk of breast cancer. Animal and in vitro studies suggest that CLAs, fatty acids found primarily in dairy products and in the meat of ruminants, have protective activities against mammary carcinogenesis. However, findings from population studies in relation to breast cancer risk are few and inconsistent. The study included 61,433 women in the Swedish Mammography Cohort who were cancer-free at enrollment during 1987 to 1990. Dietary CLA intake was determined by means of a food-frequency questionnaire at baseline. Cox proportional hazards models were used to calculate rate ratios (RRs) and 95% confidence intervals (CIs), adjusted for breast cancer risk factors. During a mean follow-up period of 17.4 years, 2,952 new cases of invasive breast cancer were diagnosed in the study group. No significant association was found between dietary CLA intake and risk of breast cancer, overall or by estrogen receptor (ER) and progesterone receptor (PR) status of the tumors. The multivariate relative risks (95% CI) for the highest fifth of CLA intake (155.7 mg/day) compared with the lowest quintile (<78.1 mg/day) were 1.04 (0.92 - 1.17) for overall breast cancer, 1.09 (0.90 - 1.31) for ER+/PR+ tumors, 1.09 (0.78 - 1.53) for ER+/PR- tumors, and 0.84 (0.57 - 1.24) for ER-/PR- tumors. The authors conclude that the results provide no evidence of a protective effect of CLA against breast cancer development in women.

The present prospective study investigated the associations between carbohydrate intake, glycemic index and glycemic load and risk of breast cancer in the Swedish Mammography Cohort. High-glycemic load diets are thought to increase the risk of breast cancer but population studies have yielded inconsistent results. The study included 61,433 women who completed a food frequency questionnaire upon enrollment in the period 1987 to 1990. During a follow-up period averaging 17.4 years, 2,952 incident cases of invasive breast cancer were diagnosed. Glycemic load but not carbohydrate intake or glycemic index was found to be weakly positively associated with risk of breast cancer (p for trend = 0.05). When stratified by tumor estrogen receptor (ER) and progesterone receptor (PR) status, significant positive associations of carbohydrate intake, glycemic index and glycemic load with risk of ER+/PR- breast cancer were found: the multivariate relative risks comparing the highest and lowest quintiles of intake were 1.34 (95% confidence interval (CI) = 0.93-1.94; p for trend = 0.04) for carbohydrate intake, 1.44 (1.06-1.97; 0.01) for glycemic index and 1.81 (1.29-2.53; 0.0008) for glycemic load. No associations were seen for ER+/PR+ or ER-/PR- breast tumors. The authors conclude that a high carbohydrate intake and diets with high glycemic index and glycemic load may increase the risk of developing ER+/PR- breast cancer.

The present study was designed to examine the association between alcohol consumption and breast cancer in postmenopausal women by breast cancer type. The study group included 184,418 postmenopausal women 50 to 71 years old in the National Institutes of Health-AARP Diet and Health Study (1995–2003). A mailed questionnaire was used at baseline to assess alcohol use, diet, and potential risk factors for cancer. Relative risks and 95% confidence intervals were calculated by using Cox proportional hazards regression. State cancer registries were used to identify breast cancer cases and estrogen receptor and progesterone receptor status. During a mean seven year follow-up period, 5,461 breast cancer cases were identified. Alcohol consumption was found to be significantly positively associated with risk of breast cancer: Even a moderate amount of alcohol (greater than 10 g/day) was shown to significantly increase risk of breast cancer. In a comparison of greater than 35 g per day versus no alcohol intake, the multivariate relative risks were found to be 1.35 (95% confidence interval (CI): 1.17-1.56) for total breast cancer, 1.46 (95% CI: 1.22-1.75) for ductal breast cancer, and 1.52 (95% CI: 0.95-2.44) for lobular tumors. The multivariate relative risk for estrogen receptor-positive/progesterone receptor-positive (ER+/PR+) tumors was 1.46 (95% CI: 1.12-1.91) for greater than 35 g per day versus no alcohol intake. The estrogen receptor-positive/progesterone receptor-negative (ER+/PR-) multivariate relative risk was 1.13 (95% CI: 0.73-1.77) for greater than 20 g versus no alcohol intake. The estrogen receptor-negative/progesterone receptor-negative (ER-/PR-) multivariate relative risk was 1.21 (95% CI: 0.79-1.84) for greater than or equal to 20 g versus no alcohol intake. The authors conclude that moderate consumption of alcohol is associated with breast cancer, especially hormone receptor-positive tumors.

The present study investigated the effects of genistein on CYP19 regulation in HepG2 liver cells. Genistein is considered a selective estrogen receptor modulator since it displays different binding affinity to different estrogen receptor (ER) isoforms. Aromatase or CYP19 is highly expressed in the ovary, which is the primary source of estrogen in pre-menopausal women. After menopause, when the ovaries stop producing the hormone, localized estrogen synthesis in other tissues become more significant physiologically. In the study, genistein was found to induce aromatase activity in HepG2 cells. Several protein kinases were examined and PKCα, P38, and ERK-1/2 were found to be involved. The transcriptional factor CREB was also found to be activated in the gene regulation. The authors comment that the study illustrated an extragonadal pathway by which genistein might increase estrogen synthesis.

The current Chinese case-control study was designed to examine the association between dietary isoflavone intake and breast cancer risk by estrogen receptor (ER) and progesterone receptor (PR) status. The study, which was conducted in southeast China during 2004–2005, included 756 incident breast cancer cases and 1,009 age-matched healthy controls recruited from outpatient breast clinics. Isoflavone intake was assessed using face-to-face interviews with a validated food-frequency questionnaire. Tumor ER and PR status was obtained from pathologic reports. Women in the highest quartile of total isoflavone intake were found to have reduced risks of all receptor status subtypes of breast cancer with a dose-response relationship compared to women in the lowest intake quartiles. The adjusted ORs (95% CIs) were 0.39 (CI = 0.27–0.58) for ER+, 0.32 (CI = 0.21–0.49) for ER−, 0.43 (CI = 0.29–0.64) for PR+, and 0.30 (CI = 0.19–0.45) for PR− (P for trend <0.001). These inverse associations persisted in both premenopausal and postmenopausal women after stratification. A stronger protective effect of high isoflavone intake was seen for breast cancer tumors with concordant rather than discordant receptor status; i.e., those with ER+/PR+ (OR 0.39, 0.26–0.59) or ER−/PR− (OR 0.28, 0.17–0.44) status. The authors comment that the finding that isoflavones protect against all tumor subtypes of breast cancer have biological plausibility since they are supported by evidence from experimental studies.

The current prospective study was designed to examine the association between dietary calcium intake and breast cancer risk by estrogen receptor (ER) and progesterone receptor (PR) status of the tumor. Calcium is thought to potentially influence breast cancer risk since it has a role in regulating cell proliferation, differentiation, and apoptosis. The study included 61,433 women in the Swedish Mammography Cohort who were cancer-free at enrollment during 1987 to 1990. Dietary calcium intake was determined by means of a food-frequency questionnaire at baseline and again in 1997. Cox proportional hazards models were used to calculate rate ratios (RRs) and 95% confidence intervals (CIs), adjusted for breast cancer risk factors. During a mean follow-up period of 17.4 years, 2,952 new cases of invasive breast cancer were diagnosed in the study group. Dietary calcium intake was found not to be associated with breast cancer risk in the group overall; the multivariate RR for the highest compared with the lowest fifth of calcium intake was 0.97 (95% CI: 0.87 - 1.09; P for trend: 0.49). However, a statistically significant inverse trend for ER-negative/PR-negative (ER-/PR-) breast cancer (P for trend: 0.02) was observed; the multivariate RR for the comparison of the highest with the lowest quintiles of calcium intake was 0.66 (95% CI: 0.44 - 0.99). Calcium intake was not found to be associated with ER+/PR+ or ER+/PR- tumors. The authors conclude that their findings do not support an association between dietary calcium intake and overall breast cancer risk and that the inverse relation between calcium intake and ER-/PR- breast cancer requires confirmation in other studies.

The current study was designed to examine the association between dietary folate intake and the risk of breast cancer by estrogen receptor (ER) and progesterone receptor (PR) status of the tumor. Folate is a B vitamin involved in one-carbon metabolism that has been postulated to affect the risk of breast cancer. However, population studies of folate intake with regard to breast cancer risk are not conclusive. Study participants included 61,433 women in the Swedish Mammography Cohort who were cancer-free at enrollment during 1987 to 1990. Dietary folate intake was determined by means of a food-frequency questionnaire at baseline and again in 1997. Cox proportional hazards models were used to calculate rate ratios (RRs) and 95% confidence intervals (CIs), adjusted for breast cancer risk factors. During a mean follow-up period of 17.4 years, 2,952 new cases of invasive breast cancer were diagnosed in the study group. Dietary folate intake was not found to be associated with breast cancer risk in the group overall; the multivariate RR for the highest compared with the lowest fifth of calcium intake was 1.01 (95% CI: 0.90-1.13; P for trend: 0.84). There were also no observed associations between dietary folate intake and risk of ER+/PR+ or ER-/PR- tumors. However, folate intake was found to be inversely associated with the risk of ER+/PR- breast cancer (n = 417 cases; RR for highest versus lowest quintile = 0.79; 95% CI, 0.59-1.07; Ptrend = 0.01). The results did not vary by alcohol intake or menopausal status. The authors conclude that the study findings do not support an overall association between folate intake and risk of breast cancer but suggest that folate intake may be inversely associated with ER+/PR– tumors.

The present case-control study was designed to investigate the associations between vitamin D and risk of breast cancer stratified by hormone receptor status. The study included 759 breast cancer cases and 1,135 cancer-free controls from a previous 2003–2005 case-control study in Ontario, Canada. In the current study, the authors calculated the association between vitamin D intake at various ages and combined hormone receptor status (estrogen receptor (ER) and progesterone receptor (PR)) of tumors. While higher intake of vitamin D (from both the sun and the diet) was found to be most consistently associated with a lower risk of ER+/PR+ breast cancer (for example, odds ratio (OR) = 0.76, 95% confidence interval (CI) = 0.59 - 0.97 for use of cod liver oil during adolescence), comparable nonsignificant associations were also observed for hormone receptor negative breast cancer (ER–/PR–) (OR = 0.74, 95% CI = 0.53 - 1.04) and mixed receptor status tumors (ER+/PR–) (OR = 0.79, 95% CI = 0.51 - 1.22). The authors conclude that vitamin D is associated with a reduced risk of breast cancer regardless of ER/PR status of the tumor.

The present study was designed to evaluate the association between dietary and supplemental intakes of carotenoids and vitamins C and E and the risk of breast cancer according to estrogen receptor (ER) and progesterone receptor (PR) status. The study group included 84,805 postmenopausal women in the Women's Health Initiative Observational Study. During an average follow-up period of 7.6 years, there were 2,879 new cases of invasive breast cancer, of which 2,509 had receptor data. Dietary α-carotene (highest versus lowest quintile: RR = 0.83; 95% CI = 0.70- 0.99; P for trend = 0.019), β-carotene (highest versus lowest quintile: RR = 0.78; 95% CI = 0.66-0.94; P = 0.021), and lycopene (highest versus lowest quintile: RR = 0.85; 95% CI = 0.73-1.00; P = 0.064) were each found to be inversely associated with the risk of ER+/PR+ breast cancer, but not with other breast cancer groups as defined by ER and PR status. Total or supplemental β-carotene and dietary intakes of lutein+zeaxanthin and β-cryptoxanthin were not found to be associated with breast cancers defined by ER and PR status. Vitamin E (regardless of source) and dietary vitamin C were found not to be associated with breast cancer. However, both total (dietary plus supplemental) and supplemental vitamin C intake were found to be weakly positively associated with breast cancer. The authors conclude that dietary intake of certain carotenoids might be differentially associated with risk of invasive breast cancers jointly defined by ER and PR status among postmenopausal women.

The current prospective study was designed to investigate the associations between plasma concentrations of folate, pyridoxal 5-phosphate (the principal active form of vitamin B-6), and vitamin B-12 and risk of breast cancer. B vitamins such as folate, vitamin B-6, and vitamin B-12 are important for DNA integrity and stability. Hence, deficiency in any of these vitamins is thought to have the potential to promote carcinogenesis. Study participants were drawn from the 28,345-member Women's Health Study cohort. Participants provided blood samples and had no history of cancer or cardiovascular disease at baseline in 1993. The study current included 848 incident cases of invasive breast cancer identified as of month-end March 2004, as well as 848 matched control subjects. Logistic regression controlling for matching factors and other risk factors for breast cancer was performed to calculate relative risks (RRs) and 95% confidence intervals (CIs). Plasma concentrations of folate, B-6, and vitamin B-12 were found not to be associated with overall breast cancer risk. Women in the highest fifth relative to those in the lowest quintile had multivariate RRs of 1.42 (95% CI: 1.00 - 2.02) for plasma folate (P for trend = 0.21), 0.91 (95% CI: 0.63 - 1.30) for plasma B-6 (P for trend = 0.48), and 1.29 (95% CI: 0.92 - 1.82) for plasma vitamin B-12 (P for trend = 0.18). However, it was found that higher plasma folate concentrations were associated with increased risk of developing premenopausal breast cancer (P for trend = 0.04) and for developing estrogen receptor positive (ER+) or progesterone receptor positive (PR+) tumors (P for trend 0.06). On the other hand, an inverse association was found between plasma B-6 and postmenopausal breast cancer (P for trend = 0.04). The authors conclude that folate, vitamin B-6, and vitamin B-12, may confer little or no reduction in overall risk of developing breast cancer. The observed positive associations of serum folate with risk of developing premenopausal breast cancer and ER+ or PR+ tumors were unexpected and require additional research to elucidate the role of folate in breast cancer development.

The present study was designed to evaluate the potential estrogenic and anti-estrogenic activities of Avlimil, a dietary supplement advertised to increase female sexual response. Avlimil is a mixture of eleven herbs, and some of these herbs (black cohosh, licorice, red raspberry, red clover and kudzu) contain compounds which have been suggested to have estrogenic, anti-estrogenic, or androgenic potential for relieving menopausal symptoms. In the study, Avlimil was investigated to see if it could modulate the growth of estrogen receptor positive (ER+) human breast cancer (MCF-7) cells in vitro and in vivo. A dimethylsulfoxide extract of Avlimil was tested for its estrogenic and anti-estrogenic effects on the growth of MCF-7 cells in vitro. The Avlimil extract at low concentrations (0.1–50 μg/mL media) was found to increase MCF-7 cell proliferation in a dose-dependent manner, whereas Avlimil extract at 100 μg/mL inhibited the growth of MCF-7 cells. Avlimil and some of its components (black cohosh and licorice roots) of Avlimil were fractionated using sequential solvent extraction and the activities of the fractions were monitored with respect to effects on the growth of MCF-7 cells. Depending on dosage, both stimulatory and inhibitory effects on the growth of MCF-7 cells were observed. Next, the effect of dietary Avlimil at dosages approximating human intake was studied using ovariectomized mice implanted with MCF-7 cells. The mice were fed diets containing 500 ppm or 1000 ppm Avlimil for 16 weeks. Dietary Avlimil at 500 ppm was found to stimulate the growth of MCF-7 tumors, but Avlimil at 1000 ppm had no observable effect on MCF-7 tumors. The authors comment that the study observation of increased tumor growth in the absence of uterine weight gain indicate that the observed estrogenic/anti-estrogenic effects of Avlimil may be dosage- and target tissue-specific and that Avlimil may not be safe for women with estrogen-dependent breast cancer.

The present prospective study was designed to investigate the association between lignan intake and risk of breast cancer in postmenopausal women by estrogen receptor (ER) and progesterone receptor (PR) subtypes. Plant lignans, which are a major type of phytoestrogen in Nordic countries, are present primarily in cereals, fruit, and vegetables. Plant lignans are metabolized to mammalian lignans such as enterolactone by intestinal microflora. The study included 51,823 postmenopausal women in the Swedish Mammography Cohort who were under 70 years old and cancer free (non-melanoma skin cancer was allowed). Information on diet was collected by means of self-administrated food-frequency questionnaires in 1987 and 1997. Total lignan intake for each woman was estimated using published values for secoisolariciresinol, matairesinol, lariciresinol, and pinoresinol. The Swedish Registration System was used to obtain date of breast cancer diagnosis, death, or migration from the study area. Information concerning the hormone receptor status of breast tumors was obtained from Uppsala University Hospital and the Regional Oncology Centre. A time-dependent multivariate Cox proportional hazards regression model was used to estimate hazard rate ratios and 95% confidence intervals with age as the time scale. During a mean follow-up period of 8.3 years, 1,284 invasive breast cancer cases were diagnosed. Details of ER/PR status was available for 1,188 cases, of which 716 were ER+/PR+, 279 were ER+/PR-, 50 were ER-/PR+, and 143 were ER-/PR- tumors. Women with high lignan intake tended to be older, better educated and more likely to use hormone replacement therapy. A significant 17% reduction in the risk of breast cancer overall was observed in the high lignan quartile, especially among postmenopausal hormone users, but there was no heterogeneity across ER/PR subtypes.

The current prospective study investigated the associations between physical activity, diet, and obesity and survival after breast cancer diagnosis. Study participants included 1,490 women diagnosed and treated for early-stage breast cancer between 1991 and 2000. The women were enrolled in the study at two years post diagnosis on average. Seven women were lost to follow-up through December 2005. In single-variable analysis, reduced mortality was found to be weakly associated with higher vegetable-fruit consumption, increased physical activity, and a body mass index that indicated neither low weight nor obesity. In a multivariate Cox model, only the combination of consuming five or more daily servings of vegetables/fruits plus accumulating at least 540 metabolic equivalent tasks-minutes per week (equivalent to walking 30 minutes, six days per week) was found to be associated with a significant survival advantage (hazard ratio, 0.56; 95% confidence interval, 0.31-0.98). The approximate 50% reduction in breast cancer metastasis risk associated with these behaviors was found in both obese and nonobese women, although fewer obese women were physically active with a high vegetable/fruit intake. In other words, among those who adhered to this healthy lifestyle, there was no observable effect of obesity on survival. The effect was stronger in women who had hormone receptor-positive (ER+/PR+) cancers.

The current prospective study examined the associations between the risk of invasive breast cancer in postmenopausal women and dietary intakes of four plant lignans (pinoresinol, lariciresinol, secoisolariciresinol, and matairesinol) and estimated exposure to two enterolignans (enterodiol and enterolactone). The study included 58,049 postmenopausal French women who were not taking soy isoflavone supplements. The women completed a self-administered diet history questionnaire. Relative risks (RRs) and 95% confidence intervals (CIs) were calculated using multivariable Cox proportional hazards regression models. Analyses were stratified by tumor combined estrogen and progesterone receptor (ER/PR) status. During a median follow-up period of 7.7 years, 1,469 cases of breast cancer were diagnosed. Women in the highest quartile of total lignan intake (greater than 1,395 µg per day) were found to have a reduced risk of breast cancer (RR = 0.83, 95% CI = 0.71-0.95, Ptrend = .02) compared to women in the lowest quartiles, as did those in the highest quartile of lariciresinol intake (RR = 0.82, 95% CI = 0.71-0.95, Ptrend = .01). The inverse associations between phytoestrogen intakes and postmenopausal breast cancer risk were restricted to ER+ and PR+ disease (RR for highest versus lowest quartiles of total plant lignan intake = 0.72, 95% CI = 0.58 - 0.88, Ptrend = .01). The authors conclude that high dietary intakes of plant lignans and high exposure to enterolignans are associated with reduced risks of ER+/PR+ postmenopausal breast cancer in a Western population that does not consume a diet rich in soy.

Nuclear factor κB (NF-κB) is a transcription factor that plays a significant role in cell inflammation, proliferation, and apoptosis. In cancer cells, NF-κB facilitates resistance to chemotherapy by promoting cell proliferation and inhibiting apoptosis. The study examined the effects of selected phytochemicals and apple extracts on NF-κB activation in hormone receptor positive human breast cancer cells. Apple extracts and curcumin both were found to inhibit NF-κB activation of breast cancer cells.

The current study was designed to evaluate the effects of sulforaphane on cell growth and death in several human breast cancer cell lines and to test the hypothesis that sulforaphane acts as a histone deacetylase (HDAC) inhibitor in these cell lines. The test cell lines included (ER-/PR-) MDA-MB-231, (ER-) MDA-MB-468, (ER+/PR+) MCF-7, and (ERα+) T47D cells. Sulforaphane, an isothiocyanate found in cruciferous vegetables, has been shown inhibit the growth of carcinogen-induced mammary tumors in rats. In the study, sulforaphane treatment was found to inhibit cell growth, induce a G2-M cell cycle block, increase expression of cyclin B1, and induce oligonucleosomal DNA fragmentation in all four human breast cancer cell lines tested. Activation of apoptosis by sulforaphane in the (ER-/PR-) MDA-MB-231 cells appeared to be initiated by induction of Fas ligand, which resulted in activation of caspase-8, caspase-3, and poly(ADP-ribose) polymerase. On the other hand, apoptosis in the remaining cell lines was initiated by decreased Bcl-2 expression, release of cytochrome c into the cytosol, activation of caspase-9 and caspase-3 (but not caspase-8) and poly(ADP-ribose) polymerase cleavage. Sulforaphane was found to inhibit HDAC activity and reduce the expression of estrogen receptor-α, epidermal growth factor receptor, and human epidermal growth factor receptor-2 in each cell line. The data indicates that sulforaphane inhibits growth, promotes apoptosis, inhibits HDAC activity, and reduces the expression of key proteins involved in breast cancer proliferation in human breast cancer cells.

The present prospective study was designed to examine the association between red meat intake and breast cancer by hormone receptor status among premenopausal women. Study participants included 90,659 women ages 26 to 46 years in the Nurses' Health Study II. Red meat intake was determined by a food frequency questionnaire administered in 1991, 1995, and 1999. Respondents were followed up through year-end 2003. Breast cancer cases were self-reported and confirmed by review of pathologic reports. During a follow-up period of 12 years, 1,021 new cases of invasive breast carcinoma were documented. Greater red meat intake was found to be strongly associated with elevated risk of breast cancers that were estrogen and progesterone receptor positive (ER+/PR+; n = 512) but not to cancers that were estrogen and progesterone receptor negative (ER–/PR–; n = 167). Compared to those consuming fewer than four servings of red meat per week, the multivariate relative risks (95% confidence intervals) for ER+/PR+ tumors with increasing servings of red meat intake were (a) 1.42 (1.06-1.90) for five to seven servings per week; (b) 1.20 (0.89-1.63) for seven to 10 1/2 servings per week; and (c) 1.97 (1.35-2.88) for more than 10 1/2 servings per week (test for trend, P = .001). The corresponding relative risks for ER-/PR- breast cancer were 1.21 (0.73-2.00), 0.69 (0.39-1.23), and 0.89 (0.43-1.84) (test for trend, P = .28). The authors conclude that higher red meat intake may be a risk factor for ER+/PR+ breast cancer among premenopausal women.

The current study was designed to assess the influence of the phytoestrogens genistein and apigenin on breast cancer growth. Genistein and apigenin are present in several commercial supplements designed to be used for postmenopausal symptoms and breast health. Both flavonoids were found to stimulate proliferation of estrogen receptor-positive/progesterone receptor-positive (ER+/PR+) MCF-7 and estrogen receptor alpha (ERα-positive) T47D breast cancer cells. However, the compounds did not stimulate the proliferation of ERα-negative MDA-MB-435 breast cancer cells. Genistein was observed to be more efficient in this regard due to its higher binding affinity for ERα. Similarly to actions previously described for estradiol (E2), both genistein and apigenin were found to down regulate ERα and enhance estrogen response element-dependent gene expression. An additional finding that genistein antagonizes the anti-proliferative effect of hydroxytamoxifen indicates that certain phytoestrogens may be detrimental for women with breast cancer who are being treated with tamoxifen. The authors conclude that because of their ability to stimulate breast cell growth, the use of phytoestrogen supplements in postmenopausal women could be detrimental.

The current study was designed to investigate the influence of oleic, linoleic and eicosapentaenoic acids on the bioavailability of β-carotene, including plasma β-carotene response and its conversion to retinol (vitamin A). The study was conducted by using single (9 hour time course) and repeated (10 days) dose administrations in rats. After a single dose, the levels of plasma β-carotene and retinyl palmitate in the oleic acid and eicosapentaenoic acid groups were higher by 13, 7 and 11, 6 folds than in the linoleic acid group (p < 0.05). The liver β-carotene level in the oleic acid and eicosapentaenoic acid groups were higher by 3 and 1.2 folds than in the linoleic acid group (p < 0.05). After 10 days' repeated dose, the plasma β-carotene and retinyl palmitate levels in oleic acid (6.2%, 51.7%) and eicosapentaenoic acid (25.4%, 17.23%) groups were higher than in the linoleic acid group (p < 0.05). The liver β-carotene level in oleic acid (21.2%) and eicosapentaenoic acid (17.6%) groups also were higher than in the linoleic acid group (p < 0.05). In both the experiments, the activity of β-carotene 15,15′-dioxygenase in the intestinal mucosa and plasma triglyceride levels were also found to be higher in the oleic acid and eicosapentaenoic acid groups than in the linoleic acid group. β-carotene excreted through the urine and feces of the oleic acid and eicosapentaenoic acid groups was lower than that of the linoleic acid group. The authors conclude that the results demonstrate an improved absorption and metabolism of β-carotene when fed a diet supplemented with oleic acid or eicosapentaenoic acid compared to linoleic acid.

The present study was designed to examine whether certain herbs alter proliferation of breast cancer cells that are estrogen receptor (ER) positive but differ in the expression of ER and ERß, and whether these herbs also alter cellular response to estradiol (E2). The breast cancer cell lines MCF-7 (60:40 ER:ERß) and T47D (33:67 ER:ERß) were treated with various strength dilutions of standard extracts of angelica (dang gui), reishi mushroom (ling zhi), licorice (gang cao), fo-ti (he show wu), and astragalus (huang qi) in the presence or absence of estradiol (1nm). Two controls were used: E2 treatment only and no treatment. The proliferation index was determined after 72 hours and values for the herbal treatments were compared to those of the controls. The MCF-7 cells were found to respond more strongly to E2 than did the T47D cells. The most noteworthy difference between these two cell lines was seen in their responses to fo-ti, reishi mushroom, and angelica. The MCF-7 cells either showed no response (fo-ti) or only a slight response (angelica and reishi mushroom) to the herbal extracts. On the other hand, the T47D cells exhibited a dose-related upswing in proliferation at higher doses of fo-ti, reishi mushroom and angelica, with the response to angelica and reishi mushroom exceeding the E2 control levels. This differential response was also found when both cancer cell lines were treated with these three herbs along with E2. In the MCF-7 cells, E2 tended to mask the effects, if any, of these herbs. In T47D cells, however, the addition of E2 to both reishi mushroom and angelica resulted in an additive effect, the proliferation index exceeding E2-stimulated levels at the higher doses. Fo-ti combined with E2 in the T47D cells was found to have no effect on E2-induced proliferation. Astragalus without E2 was found to be biphasic in both cell lines, with proliferative effects at the highest doses reaching E2 control levels in MCF-7 cells and exceeding E2 control values in T47D cells. Astragalus combined with E2 had no effect on the E2-induced proliferation in MCF-7. However, in T47D cells, astragalus plus E2 maintained a biphasic response with enhancement of proliferation at higher doses. Licorice alone showed a proliferative effect equivalent to that of the E2 control in MCF-7 cells; in T47D cells, licorice produced a strong dose response exceeding that of the E2 control. These responses did not change when E2 was added to licorice in both cell lines. These results show that some traditional Chinese medicine herbs used for immune system support may be estrogenic, and that the response differs depending on the breast cancer cell line and the presence or absence of estradiol. Generally speaking, T47D cells respond most strongly to these herbs, most likely because of their higher content of ERß, which has a higher affinity than ER for phytoestrogens. The authors conclude that the estrogenicity of these herbal preparations should be taken into account by those who want to reduce their estrogen exposure.

The present study investigated the effects of extracts of blueberries, black currant, black chokeberries, apple, sea buckthorn, plum, lingonberries, cherries, and raspberries on proliferation of hormone receptor positive breast cancer cells. The extracts decreased the proliferation of breast cancer cells and the effect was proportional to concentration. There were great variations in the antioxidants, cartenoids, flavonols, hydroxycinnamic acids, anthocyanins, phenolics and Vitamin C in the extracts. The antiproliferative effects correlated with levels of some carotenoids and with vitamin C levels. The same inhibition of cell proliferation could not be found using Vitamin C alone, suggesting a possible synergistic effect of Vitamin C and other substances.

The current case-control study was designed to examine the relationship between alcohol consumption and the risk of the most hormonally-responsive breast cancer types (i.e., lobular or hormone receptor positive breast cancers). The study included 975 women 65 to 79 years of age diagnosed with invasive breast cancer during 1997–1999 in Washington State, as well as 1,007 controls. Ever-use of alcohol over the past 20 years was found to be associated with a 1.3-fold [95% confidence interval (CI), 1.0–1.5] increased risk of breast cancer, although this increase was mostly accounted for by women who drank at least 30.0 g per day of alcohol [OR, 1.7; CI: 1.1–2.6]. Ever-use of alcohol also was found to be associated with a 1.8-fold (CI: 1.3–2.5) increased risk of lobular cancer compared to a 1.2-fold (CI: 0.9–1.4) increased risk of ductal cancer. Ever-users of alcohol had an increase in risk of ER+/PR+ tumors (OR, 1.3; CI: 1.1–1.7), but no impact was observed for their risks of ER-/PR- or ER+/PR- breast cancer. The authors conclude that alcohol use appears to be more strongly associated with lobular and hormone receptor-positive cancers than it is with other types of breast cancer.