Synchronized Seasonal Variations of Mammographic Breast Density and Plasma 25-Hydroxyvitamin D

Relationship of vitamin D deficiency with mammographic breast density and triple-negative breast cancer: A cross-sectional study

Background As breast epithelium is affected by vitamin D, it may have a direct effect on breast density and the risk of breast cancer. Our aim was to study the serum levels of vitamin D in patients with malignant and benign breast disease, and to study the association, if any, between vitamin D levels, mammographic breast density (MD) and molecular subtypes of breast cancer. Methods In this cross-sectional, observational study, we enrolled 162 consecutive adult women with benign and malignant breast masses subjected to mammography and core-needle biopsy. Serum levels of vitamin D were estimated and correlated with MD and with immunohistochemical subtyping of breast cancer. Results The mean vitamin D level in these 162 patients was 12.44 (5.88) ng/ml, with vitamin D deficiency seen in 98%. The mean (SD) vitamin D level in MD type 1 was 16.19 (4.62) ng/ml and it decreased to 7.54 (2.58) ng/ml in MD type 4. High MD was associated with significantly lower vitamin D levels. The mean vitamin D level in patients with benign breast disease (n=102) was 13.73 (5.68) ng/ml, while it was significantly lower in patients with breast cancer (n=60) at 10.26 (5.61) ng/ml. Among patients with breast cancer, the good prognosis luminal A molecular subtype had mean vitamin D level of 12.94 (6.16) ng/ml, whereas the poor prognosis triple-negative subtype had a significantly lower value of 7.68 (3.42) ng/ml. Conclusion Our study shows that vitamin D deficiency has a significant relationship with breast cancer (v. benign breast disease), high MD (showing increased breast cancer risk) and poor prognosis triple-negative breast cancer. Vitamin D deficiency could be an important, potentially modifiable, risk factor for the prevention of breast cancer in susceptible populations.

The Influence of Vitamin D on Mammographic Density: Results from CALGB 70806 (Alliance) a Randomized Clinical Trial

Current therapies for breast cancer prevention only prevent estrogen receptor positive (ER+) disease and toxicity limits use of these agents. Vitamin D is a potential prevention therapy for both ER+ and ER- disease and is safe with few side effects. This study evaluates the effect of 1-year of vitamin D supplementation on mammographic density (MD), a biomarker of breast cancer risk in a multicenter randomized controlled trial. Premenopausal women with ≥25% MD and no history of cancer were randomly assigned to 2,000 international units (IU) of vitamin D or placebo orally daily for 1 year. Change in percent MD was evaluated using Cumulus software after all participants completed treatment. Three hundred women enrolled between January 2011 and December 2013 with a mean age of 43 and diverse ethnicity [14% Hispanic, 12% African American (AA)]. Supplementation significantly increased vitamin D levels compared with placebo (14.5 ng/mL vs. -1.6 ng/mL; P < 0.0001) with all participants on the vitamin D arm achieving vitamin D sufficiency at 12 months. Vitamin D was safe and well tolerated. After adjustment for baseline MD, the mean between-arm difference (vitamin D vs. placebo) at 1 year was -0.75 (-0.26, 1.76; P = 0.56). A greater effect was seen for women with ≥50% MD and AA women, although neither reached significance. This randomized controlled trial demonstrated significant improvement in vitamin D levels with 2,000 IU for 1 year, with 100% of supplemented women achieving sufficiency. However, a null effect was seen regarding change in MD for premenopausal women (the primary outcome of the study). PREVENTION RELEVANCE: Current therapies for breast cancer prevention only prevent estrogen receptor positive (ER+) disease and are underutilized due to toxicity and side effects. Vitamin D is a potential prevention therapy for both ER+ and ER- disease and is safe with few side effects.

Serum 25-hydroxyvitamin D and mammographic density in premenopausal Spanish women

The role of vitamin D in mammographic density is still unclear. This study examines the association between serum 25-hydroxyvitamin D (25(OH)D) and mammographic density, overall and by specific women characteristics. DDM-Madrid is a cross-sectional study that recruited 1403 premenopausal women in a breast radiodiagnosis unit of Madrid City Council. Information was collected with a questionnaire and plasma 25(OH)D was measured by solid-phase extraction on-line coupled to liquid chromatography-tandem mass spectrometry. Percent mammographic density was assessed using a semi-automated computer tool (DM-Scan). Multivariable linear regression models were used to quantify the associations, categorizing 25(OH)D levels (nmol/L) into 3 groups according to the cut-offs established by the US Endocrine Society. Models were adjusted for age, education, body mass index, age at menarche, parity, previous breast biopsies, family history of breast cancer, physical activity, energy intake, use of corticoids, hypercholesterolemia and day of sample extraction. Mean serum 25(OH)D level was 49.4 + 18.9 nmol/L. Women with sufficient concentrations of 25(OH)D showed a slight decrease in mammographic density (β _>75nmol/L=-3.40; p = 0.037). No differences were observed according to women characteristics except for parity, where the protective effect of 25(OH)D was only seen among nulliparous (β _>75nmol/L=-13.00; p-heterogeneity = 0.006). In light of the protective effect of vitamin D on mammographic density and the high prevalence of vitamin D insufficiency in our population, improving these levels could be an effective measure for the prevention of health problems related to the lack of this essential vitamin.

A Randomized Double-Blind Placebo-Controlled Trial of the Effect of Vitamin D3 Supplementation on Breast Density in Premenopausal Women

Background: This double-blind, placebo-controlled parallel group trial assessed whether oral supplementation with 1,000, 2,000, or 3,000 IU/day vitamin D₃ over one year reduces percent mammographic breast density in premenopausal women.Methods: The trial was conducted between October 2012 and June 2015, among premenopausal female volunteers from Quebec City (Quebec, Canada). Women were randomized with ratio 1:1:1:1 to one of four study arms (1,000, 2,000, or 3,000 IU/day vitamin D₃ or placebo). The primary outcome was mean change in percent mammographic breast density. Participants and research team were blinded to study arm assignment.Results: Participants (n = 405) were randomized to receive 1,000 (n = 101), 2,000 (n = 104), or 3,000 IU/day (n = 101) vitamin D₃, or a placebo (n = 99). The primary analysis included 391 participants (96, 99, 100, and 96, respectively). After the one-year intervention, mean ± SE change in percent breast density in the arms 1,000 IU/day (-5.5% ± 0.5%) and 2,000 IU/day (-5.9% ± 0.5%) vitamin D₃ was similar to that in the placebo arm (-5.7% ± 0.5%) (P values = 1.0). In the 3,000 IU/day vitamin D₃ arm, percent breast density also declined but slightly less (-3.8% ± 0.5%) compared with placebo arm (P = 0.03). Adherence to intervention was excellent (92.8%), and reporting of health problems was comparable among study arms (P ≥ 0.95). All participants had normal serum calcium.Conclusions: In premenopausal women, one-year supplementation with 1,000, 2,000, or 3,000 IU/day vitamin D₃ resulted in a reduction of percent breast density no greater than that seen with the placebo.Impact: At doses of 1,000-3,000 IU/day, vitamin D supplementation will not reduce breast cancer risk through changes in breast density. Cancer Epidemiol Biomarkers Prev; 26(8); 1233-41. ©2017 AACR.

Serum 25-Hydroxyvitamin D3 and Mammography Density among Mexican Women

Low circulating levels of vitamin D and high mammographic density (MD) have been associated with higher risk of breast cancer. Although some evidence suggested an inverse association between circulating vitamin D and MD, no studies have investigated this association among Mexican women. We examined whether serum 25-hydroxyvitamin D3 [25(OH)D3] levels were associated with MD in a cross-sectional study nested within the large Mexican Teacher's Cohort. This study included 491 premenopausal women with a mean age of 42.9 years. Serum 25(OH)D3 levels were measured by liquid chromatography/tandem mass spectrometry. Linear regression and non-linear adjusted models were used to estimate the association of MD with serum 25(OH)D3. Median serum 25(OH)D3 level was 27.3 (23.3-32.8) (ng/ml). Forty one (8%) women had 25(OH)D3 levels in the deficient range (< 20 ng/ml). Body mass index (BMI) and total physical activity were significantly correlated with 25(OH)D3 (r = -0.109, P = 0.019 and r = 0.095, P = 0.003, respectively). In the multivariable linear regression, no significant association was observed between 25(OH)D3 levels and MD overall. However, in stratified analyses, higher serum 25(OH)D3 levels (≥27.3 ng/ml) were significantly inversely associated with percent MD among women with BMI below the median (β = -0.52, P = 0.047). Although no significant association was observed between serum 25(OH)D3 and percent MD in the overall population, specific subgroups of women may benefit from higher serum 25(OH)D3 levels.

Intraindividual Temporal miRNA Variability in Serum, Plasma, and White Blood Cell Subpopulations

Blood microRNAs (miRNAs) are ideal biomarkers, and blood derivatives are often collected in the scope of miRNA research projects. However, knowledge of temporal variations of miRNAs in healthy individuals is lacking. In this study, miRNA variability was measured over a 1-year period in different blood derivatives, collected every 2-3 months from two healthy donors. There is a continuum of intraindividual temporal variability, with particularly stable (coefficient of variation [CV] <20%-30%) and particularly unstable (CV >100%-130%) miRNAs in serum, plasma, and specific white blood cell subpopulations. The temporal intraindividual variability of miRNAs should be taken into consideration in experimental design of biospecimen collections and validation of diagnostic biomarkers.

Automated 3D ultrasound image segmentation to aid breast cancer image interpretation

Segmentation of an ultrasound image into functional tissues is of great importance to clinical diagnosis of breast cancer. However, many studies are found to segment only the mass of interest and not all major tissues. Differences and inconsistencies in ultrasound interpretation call for an automated segmentation method to make results operator-independent. Furthermore, manual segmentation of entire three-dimensional (3D) ultrasound volumes is time-consuming, resource-intensive, and clinically impractical. Here, we propose an automated algorithm to segment 3D ultrasound volumes into three major tissue types: cyst/mass, fatty tissue, and fibro-glandular tissue. To test its efficacy and consistency, the proposed automated method was employed on a database of 21 cases of whole breast ultrasound. Experimental results show that our proposed method not only distinguishes fat and non-fat tissues correctly, but performs well in classifying cyst/mass. Comparison of density assessment between the automated method and manual segmentation demonstrates good consistency with an accuracy of 85.7%. Quantitative comparison of corresponding tissue volumes, which uses overlap ratio, gives an average similarity of 74.54%, consistent with values seen in MRI brain segmentations. Thus, our proposed method exhibits great potential as an automated approach to segment 3D whole breast ultrasound volumes into functionally distinct tissues that may help to correct ultrasound speed of sound aberrations and assist in density based prognosis of breast cancer.

Vitamin D intake, month the mammogram was taken and mammographic density in Norwegian women aged 50-69

BACKGROUND

The role of vitamin D in breast cancer etiology is unclear. There is some, but inconsistent, evidence that vitamin D is associated with both breast cancer risk and mammographic density (MD). We evaluated the associations of MD with month the mammogram was taken, and with vitamin D intake, in a population of women from Norway--a country with limited sunlight exposure for a large part of the year.

METHODS

3114 women aged 50-69, who participated in the Norwegian Breast Cancer Screening Program (NBCSP) in 2004 or 2006/07, completed risk factor and food frequency (FFQ) questionnaires. Dietary and total (dietary plus supplements) vitamin D, calcium and energy intakes were estimated by the FFQ. Month when the mammogram was taken was recorded on the mammogram. Percent MD was assessed using a computer assisted method (Madena, University of Southern California) after digitization of the films. Linear regression models were used to investigate percent MD associations with month the mammogram was taken, and vitamin D and calcium intakes, adjusting for age, body mass index (BMI), study year, estrogen and progestin therapy (EPT), education, parity, calcium intakes and energy intakes.

RESULTS

There was no statistical significant association between the month the mammogram was taken and percent MD. Overall, there was no association between percent MD and quartiles of total or dietary vitamin D intakes, or of calcium intake. However, analysis restricted to women aged <55 years revealed a suggestive inverse association between total vitamin D intake and percent MD (p for trend = 0.03).

CONCLUSION

Overall, we found no strong evidence that month the mammogram was taken was associated with percent MD. We found no inverse association between vitamin D intake and percent MD overall, but observed a suggestive inverse association between dietary vitamin D and MD for women less than 55 years old.

Premenopausal plasma 25-hydroxyvitamin D, mammographic density, and risk of breast cancer

Epidemiologic evidence for an association between plasma 25-hydroxyvitamin D [25(OH)D] and breast cancer is inconsistent. Data are especially limited for premenopausal women and for associations with mammographic density. To test the hypothesis that plasma concentration of 25(OH)D is associated with mammographic density, we conducted a cross-sectional study among 835 premenopausal women in the Nurses' Health Studies. We measured 25(OH)D in blood samples and used multivariable linear regression to quantify the association of average percent density by quartile of plasma 25(OH)D. In a nested case-control analysis including 493 breast cancer cases, we evaluated risk of breast cancer associated with vitamin D status within tertiles of mammographic density. Women in the top quartile of plasma 25(OH)D levels had an average percent breast density 5.2 percentage points higher than women in the bottom quartile (95 % confidence interval: 1.8, 8.7; P trend <0.01), after adjusting for predictors of 25(OH)D and established breast cancer risk factors. Plasma 25(OH)D concentration was significantly inversely associated with breast cancer risk among women with high mammographic density (P trend < 0.01) but not among women in lower tertiles of mammographic density (P-interaction < 0.01). These results do not support the hypothesis that vitamin D is inversely associated with percent mammographic density in premenopausal women. There was evidence that the association between premenopausal 25(OH)D and breast cancer risk varies by mammographic density, with an inverse association apparent only among women with high mammographic density.

Association between intake of sugar-sweetened beverages and circulating 25-hydroxyvitamin D concentration among premenopausal women

Intake of sugar-sweetened beverages has increased in North America and seems to have several adverse health effects possibly through decreased circulating 25-hydroxyvitamin D (25(OH)D) concentrations. The aim of this cross-sectional study was to evaluate the association between sugar-sweetened beverages intake and 25(OH)D concentrations among premenopausal women. Intake of sugar-sweetened beverages including colas, other carbonated beverages and sweet fruit drinks was assessed using a validated food frequency questionnaire among 741 premenopausal women. Plasma concentrations of 25(OH)D were quantified by radioimmunoassay. The association between sugar-sweetened beverages intake and 25(OH)D concentrations was evaluated using multivariate generalized linear models and Spearman correlations. A higher intake of colas was associated with lower mean 25(OH)D levels (67.0, 63.7, 64.7 and 58.5 nmol/L for never, <1, 1–3 and >3 servings/week, respectively; r = −0.11 (p = 0.004)). A correlation was observed between intake of other carbonated beverages and 25(OH)D concentrations but was not statistically significant (r = −0.06 (p = 0.10)). No association was observed between intake of sweet fruit drinks and 25(OH)D concentrations. This study suggests that high intake of colas may decrease 25(OH)D levels in premenopausal women. Considering the high consumption of these drinks in the general population and the possible consequences of vitamin D deficiency on health, this finding needs further investigation.

Consumption of sweet foods and mammographic breast density: a cross-sectional study

BACKGROUND

The increasing consumption of sugar worldwide seems to lead to several health problems, including some types of cancer. While some studies reported a positive association between sweet foods intake and breast cancer risk, little is known about their relation to mammographic density (MD), a strong breast cancer risk factor. This study examined the association of sweet foods and drinks intake with MD among 776 premenopausal and 779 postmenopausal women recruited at mammography.

METHODS

A food-frequency questionnaire was used to assess intake of sweet foods, sugar-sweetened beverages and spoonsful of sugar added. Percent and absolute breast density were estimated using a computer-assisted method. Multivariate generalized linear models were used to evaluate associations. All models were adjusted for potential confounders, including age and body mass index.

RESULTS

For increasing quartiles of sugar-sweetened beverages intake, adjusted-mean absolute density was respectively 32, 34, 32 and 36 cm2 among all women (P(trend) = 0.040) and 43, 46, 44 and 51 cm2 among premenopausal women (P(trend) = 0.007). For increasing quartiles of sweet foods intake, adjusted-mean percent density was respectively 16, 16, 17 and 19% among postmenopausal women (P(trend) = 0.036). No association was shown between intake of spoonsful of sugar added and MD.

CONCLUSION

Our results suggest that an increase in sweet foods or sugar-sweetened beverage intake is associated with higher MD.

Mammographic density and serum 25-hydroxyvitamin D levels

Background

Vitamin D, which influences cellular proliferation and breast tissue characteristics, has been inversely correlated with breast cancer risk. Dietary vitamin D intake has been associated with lower mammographic density (MD), a strong intermediate marker of breast cancer risk.

Findings

We examined the relationship between MD and serum 25-hydroxyvitamin D [25(OH)D], an integrated measure of vitamin D status from dietary sources and sunlight exposure, in a multi-ethnic cohort of women undergoing screening mammography. We recruited women age 40–60 years without a history of breast cancer at the time of their routine screening mammogram, and conducted in-person interviews and collected blood specimens. We enrolled 195 women from 2007–2008, 120 gave blood, and 114 were evaluable, including 25% white, 41% African American, 18% African Caribbean, and 16% Hispanic. We digitized mammograms and calculated percent density, dense area, and non-dense area on cranial-caudal images. We measured serum 25(OH)D in batched, archived specimens. Median serum 25(OH)D was 22 ng/ml (range, 8–66 ng/ml). In univariable analysis, higher serum 25(OH)D was associated with white race, higher educational level, ever breast feeding, and blood draw during the summer. After adjusting for body mass index and other confounders, we found no association between serum 25(OH)D and different measures of MD. However, when stratified by season, 25(OH)D was inversely associated with dense area during July-December (p = 0.034).

Conclusions

Overall, our findings suggest that circulating vitamin D, a potentially modifiable breast cancer risk factor, is not associated with MD; the seasonal effects we observed need to be replicated in larger cohorts.

Serum factors and clinical characteristics associated with serum E-screen activity

BACKGROUND

The E-Screen bioassay can measure the mitogenicity of human serum and thus may be useful as a biomarker in epidemiologic studies of breast cancer. While the assay's MCF-7 cells are known to proliferate in response to estrogen, the specific determinants of variation in E-Screen activity in human serum samples are poorly understood. We sought to identify serum molecules and patient characteristics associated with serum E-Screen activity among postmenopausal women.

METHODS

Postmenopausal women (N = 219) aged 55 to 70 years with no history of postmenopausal hormone use or breast cancer completed a questionnaire and provided a blood sample. Serum was analyzed for E-Screen activity and a variety of molecules including sex hormones, growth factors, and environmental chemicals. Stepwise selection procedures were used to identify correlates of E-Screen activity.

RESULTS

Serum samples from all women had detectable E-Screen activity, with a median estradiol equivalents value of 0.027 ng/mL and interquartile range of 0.018-0.036 ng/mL. In the final multivariable-adjusted model, serum E-Screen activity was positively associated with serum estradiol, estrone, insulin-like growth factor-binding protein (IGFBP)-3, and testosterone levels (all P < 0.05), as well as body mass index (P = 0.03). Serum E-Screen activity was lower among women with higher SHBG (P < 0.0001) and progesterone levels (P = 0.03).

CONCLUSION

Serum E-Screen activity varies according to levels of endogenous estrogens and other serum molecules. Obesity appears to confer additional serum mitogenicity beyond its impact on the measured hormones and growth factors.

IMPACT

By capturing mitogenicity due to a variety of patient and serum factors, the E-Screen may provide advantages for use as a biomarker in breast cancer studies.

Vitamin d: are we ready to supplement for breast cancer prevention and treatment?

Vitamin D deficiency is a potentially modifiable risk factor that may be targeted for breast cancer prevention and treatment. Preclinical studies support various antitumor effects of vitamin D in breast cancer. Numerous observational studies have reported an inverse association between vitamin D status, including circulating 25-hydroxyvitamin D (25(OH)D) levels, and breast cancer risk. The relationship between vitamin D and mammographic density, a strong predictor of breast cancer risk, remains unclear. Studies analyzing the link between genetic polymorphisms in vitamin D pathway genes and breast cancer incidence and prognosis have yielded inconsistent results. Vitamin D deficiency among breast cancer patients has been associated with poorer clinical outcomes and increased mortality. Despite a number of clinical trials of vitamin D supplementation, the efficacy, optimal dosage of vitamin D, and target blood level of 25(OH)D for breast cancer prevention have yet to be determined. Even with substantial literature on vitamin D and breast cancer, future studies need to focus on gaining a better understanding of the biologic effects of vitamin D in breast tissue. Despite compelling data from experimental and observational studies, there is still insufficient data from clinical trials to make recommendations for vitamin D supplementation for breast cancer prevention or treatment.

Diet across the Lifespan and the Association with Breast Density in Adulthood

Studies have shown inconsistent results regarding the association between dietary factors across the lifespan and breast density and breast cancer in women. Breast density is a strong risk factor for breast cancer, and the mechanism through which it influences cancer risk remains unclear. Breast density has been shown to be modifiable, potentially through dietary modifications. The goal of this paper is to summarize the current studies on diet and diet-related factors across all ages, determine which dietary factors show the strongest association with breast density, the most critical age of exposure, and identify future directions. We identified 28 studies, many of which are cross-sectional, and found that the strongest associations are among vitamin D, calcium, dietary fat, and alcohol in premenopausal women. Longitudinal studies with repeated dietary measures as well as the examination of overall diet over time are needed to confirm these findings.

Rotating night shift work and mammographic density

BACKGROUND

An increased risk of breast cancer has been observed in night shift workers. Exposure to artificial light at night and disruption of the endogenous circadian rhythm with suppression of the melatonin synthesis have been suggested mechanisms. We investigated the hypothesis that rotating night shift work is associated with mammographic density.

METHODS

We conducted a cross-sectional study on the association between rotating night shift work characteristics, 6-sulfatoxymelatonin (MT6s) creatinine adjusted in a spot morning urine sample, and a computer-assisted measure of mammographic density in 640 nurses and midwives ages 40 to 60 years. The associations were evaluated using regression models adjusted for age, body mass index, menopausal status, age at menopause, age at menarche, smoking, and the calendar season of the year when mammography was conducted.

RESULTS

The adjusted means of percentage of mammographic density and absolute density were slightly higher among women working rotating night shifts but not statistically significant [percentage of mammographic density = 23.6%, 95% confidence interval (CI), 21.9%-25.4% vs. 22.5%, 95% CI, 20.8%-24.3%; absolute density = 23.9 cm(2), 95% CI, 21.4-26.4 cm(2) vs. 21.8 cm(2), 95% CI, 19.4-24.3 cm(2) in rotating night shift and day shift nurses, respectively). There were no significant associations between the current or cumulative rotating night shift work exposure metrics and mammographic density. No association was observed between morning MT6s and mammographic density.

CONCLUSIONS

The hypothesis on the link between rotating night shift work, melatonin synthesis disruption, and mammographic density is not supported by the results of the present study.

IMPACT

It is unlikely that the development of breast cancer in nurses working rotating night shifts is mediated by an increase in mammographic density.

Vitamin D and calcium supplementation and one-year change in mammographic density in the women's health initiative calcium and vitamin D trial

BACKGROUND

Calcium and vitamin D may be inversely related to breast cancer risk, in part by affecting mammographic density. However, results from previous, mostly cross-sectional studies have been mixed, and there have been few randomized clinical trials of the effect of calcium and vitamin D supplementation on change in mammographic density.

METHODS

We assessed the effect of one year of supplementation on mammographic density in 330 postmenopausal women enrolled in the Women's Health Initiative hormone therapy (HT) and calcium and vitamin D (CaD) trials. Women were randomized to receive 1,000 mg/d of elemental calcium carbonate plus 400 IU/d of vitamin D(3) or placebo.

RESULTS

After approximately one year, mammographic density decreased 2% in the CaD supplementation group and increased 1% in the placebo group (ratio of means = 0.97; 95% CI = 0.81-1.17). Results suggested potential interaction by HT use (P = 0.08). Among women randomized to HT placebo, the ratio of mean density comparing CaD supplementation and placebo groups was 0.82 (95% CI = 0.61-1.11) vs. 1.16 (95% CI = 0.92-1.45) in women randomized to active HT. In sensitivity analyses limited to women taking ≥ 80% of study supplements, ratios were 0.67 (95% CI = 0.41-1.07) in women not assigned to HT and 1.07 (95% CI = 0.79-1.47) women assigned to HT.

CONCLUSIONS

We observed no overall effect of vitamin D and calcium supplementation on mammographic density after one year.

IMPACT

Potential interaction between these nutrients and estrogen as related to mammographic density warrants further study.

Plasma components affect accuracy of circulating cancer-related microRNA quantitation

Circulating microRNAs (miRNAs) have emerged as candidate biomarkers of various diseases and conditions including malignancy and pregnancy. This approach requires sensitive and accurate quantitation of miRNA concentrations in body fluids. Herein we report that enzyme-based miRNA quantitation, which is currently the mainstream approach for identifying differences in miRNA abundance among samples, is skewed by endogenous serum factors that co-purify with miRNAs and anticoagulant agents used during collection. Of importance, different miRNAs were affected to varying extent among patient samples. By developing measures to overcome these interfering activities, we increased the accuracy, and improved the sensitivity of miRNA detection up to 30-fold. Overall, the present study outlines key factors that prevent accurate miRNA quantitation in body fluids and provides approaches that enable faithful quantitation of miRNA abundance in body fluids.

Vitamin D and mammographic breast density: a systematic review

Studies suggest a protective relationship between Vitamin D and breast cancer risk. Several studies assessed the association of Vitamin D with mammographic breast density, a known and strong breast cancer risk factor. Understanding the potential role of Vitamin D in the modification of breast density might open new avenues in breast cancer prevention. This systematic review summarizes published studies that investigated the association between Vitamin D and mammographic breast density and offers suggestions for strategies to advance our scientific knowledge.

Mammographic density and intake of selected nutrients and vitamins in Norwegian women

Investigating the association between dietary factors and mammographic density (MD) could shed light on the relationship between diet and breast cancer risk. We took advantage of a national mammographic screening program to study the association between intake of nutrients and MD. In this study, we analyzed data of 2,252 postmenopausal women aged 50-69 yr who participated in the Norwegian Breast Cancer Screening Program in 2004. MD was assessed on digitized mammograms using a computer-assisted method. We used multivariate linear regression models to determine least square means of percent and absolute MD. Overall, we observed no associations between MD and intake of total calories, protein, carbohydrates, cholesterol, and dietary fiber. There was a positive borderline statistically significant association between absolute MD and total fat intake (P = 0.10) and between percent MD and intake of saturated fat (P = 0.06). There was no association between MD and intake of calcium, retinol, vitamins A, B12, C, or D, or combined intake of vitamin D and calcium. This study provides some evidence of an association between MD and dietary intake. Our study highlights the importance of adequate adjustments for BMI in studies of diet and MD.

The vitamin D pathway and mammographic breast density among postmenopausal women

Laboratory studies have demonstrated that vitamin D has a number of chemopreventive properties, and that these properties may be mediated or modified by other molecules in the vitamin D pathway, such as parathyroid hormone (PTH) or calcium. However, there is little epidemiologic data exploring the effects of vitamin D on breast cancer risk in the context of these other molecules. We examined a panel of molecules in the vitamin D pathway in relation to mammographic breast density, a marker of breast cancer risk, in the Wisconsin Breast Density Study. A total of 238 postmenopausal women (ages 55-70, with no history of postmenopausal hormone use) were enrolled from mammography clinics in Madison, Wisconsin. Subjects provided blood samples that were analyzed for levels of 25-hydroxy vitamin D [25(OH)D], PTH, insulin-like growth factor-1 (IGF-1), IGF-binding protein 3 (IGFBP-3), retinol, and calcium. Percent breast density was measured using Cumulus software. In age-adjusted analyses there was a positive association between 25(OH)D and percent breast density (P = 0.05; mean percent density = 11.3% vs. 15.6% for 1st vs. 4th quartile of 25(OH)D). Breast density was inversely associated with PTH (P = 0.05; 16.0% vs. 11.4% for Q1 vs. Q4) and positively associated with the IGF-1:IGFBP-3 molar ratio (P = 0.02; 11.9% vs. 15.6% for Q1 vs. Q4). However, these associations were all null after further adjustment for body mass index (BMI; P > 0.25). The independent relation between 25(OH)D and breast density remained null among subgroups defined by BMI and serum levels of retinol, calcium, and estradiol. These results suggest no strong independent associations between the circulating molecules of the vitamin D pathway and mammographic breast density in postmenopausal women. While it remains possible that vitamin D could influence breast cancer risk, our results suggest that such an effect would be mediated through pathways other than breast density.

Comparative study of density analysis using automated whole breast ultrasound and MRI

PURPOSE

The purpose of this study is to compare the measurements of breast density using three-dimensional (3-D) automated whole breast ultrasound (ABUS) and magnetic resonance imaging (MRI).

METHODS

In this study, 3-D ABUS and MRI breast images were obtained from 40 patients-bilaterally in 27 patients and unilaterally (due to operation in the contralateral breast) in 13 patients, To differentiate the fibroglandular and fatty tissues in ABUS and MRI images, the fuzzy C-mean classifier was used. Calculated values for percent density and breast volume from the two modalities were compared to and correlated with linear regression analysis. Intraoperator and interoperator variations among eight cases were evaluated to verify the consistency of the density analysis.

RESULTS

Mean percent density and breast volume derived from ABUS (17.63 +/- 11.87% and 418.30 +/- 132.97 cm3, respectively) and MRI images (23.79 +/- 16.62% and 544.90 +/- 207.41 cm3) demonstrated good correlation (R = 0.917 and R = 0.884). Intraoperator and interoperator analyses yielded slightly larger coefficients of variation for percent density and breast volume in ABUS compared to MRI. However, the differences were not statistically significant.

CONCLUSIONS

ABUS and MRI showed high correlation for breast density and breast volume quantification. Both modalities could provide useful breast density information to physicians.

Dietary vitamin D and calcium intake and mammographic density in postmenopausal women

OBJECTIVE

Dietary intake of vitamin D and calcium may be related to risk of breast cancer, possibly by affecting mammographic density. However, the few studies that have evaluated the association between these nutrients and mammographic density in postmenopausal women have had inconsistent results.

METHODS

We conducted a cross-sectional analysis in 808 participants of the Mammogram Density Ancillary Study of the Women's Health Initiative. Mammographic percent density was measured using baseline mammograms taken before randomization of participants in the intervention trials. Vitamin D and calcium intake was assessed with a validated food frequency questionnaire and an inventory of current supplement use, both completed at baseline.

RESULTS

After adjustment for age, body mass index, regional solar irradiance, and other factors, we did not find a relationship between vitamin D or calcium intake and mammographic density. Mean mammographic percent densities in women reporting total vitamin D intakes of less than 100, 100 to 199, 200 to 399, 400 to 599, and 600 or greater IU/day were 5.8%, 10.4%, 6.2%, 3.8%, and 5.1%, respectively (P trend = 0.67). Results in women reporting a total calcium intake of less than 500, 500 to 749, 750 to 999, 1,000 to 1,199, and 1,200 or greater mg/day were 7.3%, 4.9%, 7.3%, 6.9%, and 7.11%, respectively (P trend = 0.51). We did not observe any effect modification by overall level of mammographic density or solar irradiance, but supplemental vitamin D use was associated with lower density in younger women (P interaction = 0.009).

CONCLUSIONS

These findings do not support a relationship between dietary vitamin D or calcium intake and mammographic density in postmenopausal women. Additional studies should explore these associations in women of different ages and in relation to serum vitamin D levels.

The relationship between vitamin D and breast cancer incidence and natural history

Endocrine action of vitamin D and its role in calcium homeostasis and bone health are well known. The discovery that breast epithelial cells possess the same enzyme system as the kidney, permitting local manufacture of active vitamin D (1,25 dihydroxyvitamin D, or 1,25[(OH)(2)D]) from circulating precursors 25 hydroxyvitamin D [25(OH)D], has suggested an autocrine role for vitamin D, as well. Preclinical and ecologic studies support a role of vitamin D in prevention of breast cancer. Correlative study results of vitamin D intake or measurement of 25(OH)D, the long-lived precursor, are mixed but suggest a protective effect in premenopausal women. The large Women's Health Initiative failed to show any reduction in breast cancer incidence in postmenopausal women with a modest amount of vitamin D supplementation. Lack of effect, however, may have been related to trial design. A recent report also suggests that vitamin D may reduce breast cancer recurrence and mortality. Finally, vitamin D is being investigated as a means to reduce aromatase inhibitor-induced joint symptoms.

Mammographic density, plasma vitamin D levels and risk of breast cancer in postmenopausal women

Mammographic density is a strong risk factor for breast cancer, but the underlying biology for this association is unknown. Studies suggest that vitamin D may reduce breast cancer risk and dietary vitamin D intake has been associated with reduced breast density. We conducted a case-control study nested within the Nurses' Health Study cohort consisting of 463 and 497 postmenopausal cases and controls, respectively. We examined the association between mammographic density and plasma levels of 25-hydroxyvitamin D [25(OH)D] and 1,25-dihydroxyvitamin D [1,25(OH)(2)D]. We assessed whether plasma vitamin D metabolites modify the association between breast density and breast cancer. Percent mammographic density was measured from digitized film mammograms. Generalized linear models were used to determine mean percent breast density per quartile of vitamin D metabolite. Logistic regression models were used to calculate relative risks and confidence intervals. All models were adjusted for matching variables and potential confounders. We found no cross-sectional association between circulating levels of 25(OH)D or 1,25(OH)(2)D with mammographic density. Women in the highest tertile of mammographic density and lowest tertile of plasma 25(OH)D had 4 times greater risk of breast cancer than women with the lowest mammographic density and highest plasma 25(OH)D levels (RR = 3.8; 95% CI: 2.0-7.3). The overall interaction between mammographic density and plasma 25(OH)D was nonsignificant (p-het = 0.20). These results indicate that the association between mammographic density and breast cancer is independent of plasma vitamin D metabolites in postmenopausal women. Further research examining vitamin D, mammographic density and breast cancer risk is warranted.

Genomic vitamin D signaling in breast cancer: Insights from animal models and human cells

These studies focus on identification of vitamin D regulated pathways that impact development or progression of breast cancer. In mouse experiments, we assessed genomic profiles of glandular tissue and established tumors from MMTV-neu mice fed adequate (250 IU/kg) or high (5000 IU/kg) vitamin D (cholecalciferol). Genomic profiles were also obtained in murine mammary cells that differentially express VDR that were cultured in vitro with 100 nM 1,25-dihydroxyvitamin D (1,25D). Ten candidate genes were identified that were commonly regulated in murine cells treated with 1,25D in vitro and in mammary gland of mice fed high dietary vitamin D. In complementary studies, the vitamin D pathway was evaluated in human mammary epithelial cells as a function of transformation. Genes regulated by 1,25D in human mammary epithelial cells included those involved in innate immunity (CD14), differentiation (Bmp6), extracellular matrix remodeling (Plau) and cell survival (Birc3). Transformation reduced VDR content and blunted the induction of some, but not all, target genes by 1,25D in human mammary cells. Collectively, these in vivo and in vitro data demonstrate that vitamin D signaling impacts on common pathways that drive differentiation, alter metabolism, remodel the extracellular matrix and trigger innate immunity in mammary tissue.

Serum 25-hydroxyvitamin D levels and mammographic density among premenopausal women in a multiethnic population

Although some evidence suggests a protective role of vitamin D against breast cancer, epidemiological findings are inconsistent. The current study investigated the relation of serum 25-hydroxyvitamin D (25(OH)D) levels with mammographic density. Baseline serum samples from 182 premenopausal women including 67 Caucasians and 74 Asians from a nutritional trial were analyzed for 25(OH)D. Mammographic density was assessed using a computer-assisted method. Serum 25(OH)D was not associated with mammographic density after adjustment for confounders (body mass index (BMI), age at mammogram, Asian ethnicity, age at first birth, parity and age at menarche). 25(OH)D levels were significantly lower in Asians than in Caucasians, but no significant ethnic differences in mammographic density were observed after adjusting for BMI. Although the current results indicate that serum 25(OH)D levels were not associated with mammographic density among premenopausal women, a possible protective effect of vitamin D against breast cancer may be mediated through other pathways.

The "Got D'ViBE?" study: an inter-institutional project assessing vitamin D and mammographic breast density

A multi-institutional collaboration was forged to implement a study of the relationship between Vitamin D and breast density among medically underserved women. This effort resulted in techniques to measure vitamin D levels, breast density, and sunlight exposure. Outcomes from this collaboration may provide insight to researchers conducting similar investigations.

Serum vitamin D and breast density in breast cancer survivors

BACKGROUND

Vitamin D influences cellular proliferation and proliferation-related breast tissue characteristics, such as mammographic breast density. Little is known about vitamin D status, assessed by serum 25-hydroxyvitamin D [25(OH)D], and its relationship to breast density in breast cancer survivors.

METHODS

Participants were 426 postmenopausal breast cancer survivors from the Health, Eating, Activity, and Lifestyle Study. Women from New Mexico, Los Angeles, and western Washington were enrolled postdiagnosis. Data for this report are from an examination conducted 24 months postenrollment. Participants completed health-related questionnaires, gave fasting blood samples, and completed height and weight measurements. Serum [25(OH)D] was assayed by radioimmunoabsorbant assay. Breast dense area and percent density were measured from postdiagnosis-digitized mammograms. Multivariate linear regression tested associations of serum [25(OH)D] with mammographic breast density measures.

RESULTS

Of the 426 participants, 22.8% were African-American, 11.3% were Hispanic, and 62.8% were non-Hispanic white. We observed no associations of serum [25(OH)D] with either breast density or breast dense area. Among women with vitamin D deficiency (serum [25(OH)D], <16.0 ng/mL; n = 103), mean percent breast density was 8.0%, and among those with sufficient status (n = 99; serum [25(OH)D], > or = 32.0 ng/mL), mean percent density was 8.5%. Breast dense area averaged 27.2 and 26.2 cm2 for women with vitamin D deficiency and sufficiency, respectively.

CONCLUSION

Data from this multiethnic cohort of breast cancer survivors do not support the hypothesis that serum vitamin D, [25(OH)D], is associated with breast density in cancer survivors.

Predictors of death after severe Streptococcus pyogenes infection

An evaluation of the relative importance of host and pathogen factors on the survival rate of patients with invasive Streptococcus pyogenes infection found a number of clinical and demographic factors to be associated with risk for death. Some evidence suggested a seasonal pattern to patient survival rate.

Meta-analysis of vitamin D, calcium and the prevention of breast cancer

Vitamin D and calcium intake have been suggested to have protective effects against breast cancer; however, the data have been inconclusive. The present meta-analysis examined the overall effects of vitamin D intake, circulating 25(OH)D and 1alpha,25(OH)(2)D levels, and calcium intake on breast cancer risk. Data from 11 studies on vitamin D intake, 7 studies on circulating 25(OH)D levels, 3 studies of circulating 1alpha,25(OH)(2)D levels, and 15 studies on calcium intake and breast cancer risk were included in this analysis. From the meta-analysis, there was a significant inverse relationship between vitamin D intake and breast cancer risk, with an overall relative risk (RR) of high versus low vitamin D intake for breast cancer of 0.91 (95% CI = 0.85-0.97). The highest quantile of circulating 25(OH)D was found to be associated with a 45% (OR = 0.55, 95% CI = 0.38-0.80) decrease in breast cancer when compared with the lowest quantile. No significant association for the circulating 1alpha,25(OH)(2)D level and breast cancer was found (OR = 0.99, 95% CI = 0.68-1.44). For calcium, a 19% (RR = 0.81, 95% CI = 0.72-0.90) decrease in breast cancer risk was found for those with highest quantile of calcium intake compared to the lowest quantile. These results provide strong evidence that vitamin D and calcium have a chemopreventive effect against breast cancer.

Association of leptin, 25-hydroxyvitamin D, and parathyroid hormone in women

Vitamin D deficiency and adipocytokines have been implicated in the etiology of aging-related diseases such as cancer, osteoporosis, and diseases of the cardiovascular system. The association between elevated parathyroid hormone (PTH) and low 25-hydroxyvitamin D (25-OH-VitD) in plasma is used to define vitamin D deficiency, yet their associated mechanistic pathways are unclear. Utilizing plasma samples from women in a previous intervention study, we measured plasma 25-OH-VitD, leptin, adiponectin, PTH, and lipid levels. We observed strong positive associations for leptin with PTH, gamma -tocopherol, and body mass index (BMI) and inverse associations with 25-OH-VitD and adiponectin. Although commonly accepted that vitamin D deficiency causes hyperparathyroidism, we observed this association primarily in individuals with elevated leptin levels, suggesting that leptin may be an important modifier of this effect consistent with 25-OH-VitD-mediated inhibition of leptin. Leptin was highly correlated with the BMI/25-OH-VitD ratio (r = 0.80; P < 0.0001), consistent with a model in which BMI (adiposity) and 25-OH-VitD are the primary determinants of circulating leptin and PTH levels. This model may explain the failure of some studies to observe elevated PTH in vitamin D deficient adolescents and provides important insight into epidemiological studies exploring the associations of these individual biomarkers with chronic disease risk and mortality.

The beneficial role of vitamin D and its analogs in cancer treatment and prevention

BACKGROUND

Cancer is the leading cause of death in the United States, and the probability of developing cancer increases dramatically with age. Interestingly, vitamin D deficiency is also recognized more often in people of advanced ages. A potential relationship between vitamin D deficiency and cancer has been reported in the literature.

METHOD

Review Medline database literature and discuss the relationship between vitamin D status and cancer.

RESULTS

Environmental (including seasonal and geographic) and genetic factors contribute to the development of both vitamin D deficiency and cancer. The vitamin D receptor is present in many tissues, especially in malignant cells, and may contribute to the successful use of vitamin D and its analogs in the treatment of some cancer patients.

CONCLUSION

Further investigation of the role of vitamin D in the treatment of cancer is warranted.

Genetic polymorphisms of the vitamin D binding protein and plasma concentrations of 25-hydroxyvitamin D in premenopausal women

BACKGROUND

Vitamin D status, determined on the basis of 25-hydroxyvitamin D [25(OH)D] concentrations, is associated with the risk of several diseases. Vitamin D binding protein (DBP) is the major carrier of vitamin D and its metabolites, but the role of DBP single nucleotide polymorphisms (SNPs) on 25(OH)D concentrations is unclear.

OBJECTIVE

The objective was to evaluate the association of 2 DBP gene SNPs with 25(OH)D concentrations and explore whether such association varies according to the amount of vitamin D that needs to be transported.

DESIGN

This cross-sectional study included 741 premenopausal white women, mostly of French descent. Plasma 25(OH)D concentrations were measured by radioimmunoassay. DBP-1 (rs7041) and DBP-2 (rs4588) were genotyped with a Sequenom MassArray platform. Associations and interactions were modeled by using multivariate linear regression.

RESULTS

DBP-1 and DBP-2 SNPs were in strong linkage disequilibrium and were both associated with 25(OH)D concentrations. An additional copy of the rare allele of DBP-1 or DBP-2 was associated with lower 25(OH)D concentrations (beta = -3.29, P for trend = 0.0003; beta = -4.22, P for trend < 0.0001, respectively). These DBP polymorphisms explained as much of the variation in circulating 25(OH)D as did total vitamin D intake (r2 = 1.3% for DBP-1, r2 = 2.0% for DBP-2, and r2 < or = 1.2% for vitamin D intake).

CONCLUSION

Circulating 25(OH)D concentrations in premenopausal women are strongly related to DBP polymorphisms. Whether DBP rare allele carriers have a different risk of vitamin D-related diseases and whether such carriers can benefit more or less from dietary interventions, vitamin D supplementation, or sun exposure need to be clarified.

Vitamin D receptor polymorphisms (FokI, BsmI) and breast cancer risk: association replication in two case-control studies within French Canadian population

Vitamin D has been associated with reduced breast cancer risk. We studied the association of two vitamin D receptor (VDR) gene single nucleotide polymorphisms restriction enzyme detecting SNP of VDR (FokI and BsmI) with breast cancer risk in two independent case-control studies carried out in the same population. The modifying effect of family history of breast cancer on this relationship was also evaluated. The first and second studies included respectively 718 (255 cases/463 controls) and 1596 (622 cases/974 controls) women recruited in Quebec City, Canada. FokI and BsmI genotypes were assessed. Relative risks of breast cancer were estimated by multivariate logistic regression. Compared with homozygotes for the common F allele (FF genotype), FokI ff homozygotes had a higher breast cancer risk (study 1: odds ratio (OR)=1.22, 95% confidence interval (CI)=0.76-1.95; study 2: OR=1.44, 95% CI=1.05-1.99; and combined studies: OR=1.33, 95% CI=1.03-1.73). Significant interactions were observed between FokI and family history of breast cancer in the two studies as well as in the combined analysis (P interaction=0.031, 0.050 and 0.0059 respectively). Among women without family history, odds ratios were 1.00, 1.27 (95% CI=1.02-1.58) and 1.57 (95% CI=1.18-2.10) respectively for FF, Ff and ff carriers (P(trend)=0.0013). BsmI Bb+bb genotypes were associated with a weak non-significant increased risk in the two studies (combined OR=1.22, 95% CI=0.95-1.57) without interaction with family history. Results support the idea that vitamin D, through its signalling pathway, can affect breast cancer risk. They also suggest that variability in observed associations between VDR FokI and breast cancer from different studies may partly be explained by the proportion of study subjects with a family history of breast cancer.

Vitamin D intake and breast cancer risk: a case-control study in Italy

BACKGROUND

Vitamin D has been suggested to play a protective role against several cancers, including breast cancer.

PATIENTS AND METHODS

We used data from a case-control study conducted in Italy from 1991 to 1994 to study the relation between dietary intake of vitamin D and breast cancer risk. Subjects were 2569 women with incident, histologically confirmed breast cancer and 2588 hospital controls. Odds ratios (ORs) and 95% confidence intervals (CIs) according to deciles of vitamin D intake were estimated by multiple logistic regression models.

RESULTS

After allowance for major risk factors for breast cancer and dietary covariates including calcium and energy intake, there was no association with vitamin D up to the seventh decile. Thereafter, the OR declined, so that the overall trend was statistically significantly inverse. The OR for subjects in the three highest deciles of consumption compared with those in the lowest ones combined was 0.79 (95% CI 0.70-0.90). Intake of vitamin D >3.57 microg or 143 IU appeared to have a protective effect against breast cancer. The inverse association was consistent across strata of menopausal status.

CONCLUSIONS

This study adds to the existing evidence that vitamin D intake in inversely associated with breast cancer risk.

Multivitamin-multimineral supplement use and mammographic breast density

BACKGROUND

The effect of multivitamin-multimineral supplements on the occurrence of chronic diseases, such as breast cancer, is unclear. Breast density is increasingly used as a biomarker of breast cancer risk.

OBJECTIVE

The present study evaluated the association of multivitamin-multimineral supplement use with breast density.

DESIGN

Premenopausal (n = 777) and postmenopausal (n = 783) women were recruited at the time of screening mammography. Anthropometric measurements were taken at recruitment. Demographic characteristics, behavioral factors, and health conditions were documented by telephone interview. Diet and multivitamin-multimineral and individual vitamin and mineral supplement use were assessed with a self-administered food-frequency questionnaire. Breast density from screening mammograms was measured using a computer-assisted method. Crude and adjusted means in breast density were evaluated according to multivitamin-multimineral supplement use using generalized linear models.

RESULTS

Current multivitamin-multimineral supplement use was reported by 21.7% of women (20.7% and 22.6% of premenopausal and postmenopausal women, respectively). Premenopausal women who were currently using multivitamin-multimineral supplements had higher adjusted mean breast density (45.5%) than past (42.9%) or never (40.2%) users (P for heterogeneity = 0.03, P for trend = 0.009). Of the current users, breast density was not related to duration of multivitamin-multimineral supplement use. In postmenopausal women, multivitamin-multimineral supplement use was not associated with breast density (P for heterogeneity = 0.53, P for trend = 0.40).

CONCLUSION

Regular use of multivitamin-multimineral supplements may be associated with higher mean breast density among premenopausal women. The relations of multivitamin-multimineral supplement use to breast density and breast cancer risk need to be clarified.

Dietary intake and breast density in high-risk women: a cross-sectional study

Background

Women with a family history of breast cancer may be at higher risk for breast cancer, but few previous studies evaluating diet and breast cancer have focused on such women. The objective of the present study was to determine whether diet, a modifiable risk factor, is related to breast density among women at high genetic risk for breast cancer.

Methods

Women with at least one first-degree or second-degree relative with breast cancer or ovarian cancer participating in the Fox Chase Cancer Center Family Risk Assessment Program completed health history and food frequency questionnaires and received standard screening mammograms. Cranial–caudal mammographic images were classified into the four Breast Imaging Reporting and Data System categories ranging from 'entirely fatty' to 'extremely dense'. Logistic regression analysis using proportional odds models for polychotomous outcomes provided estimates of odds ratios for having a higher category versus a lower category of breast density.

Results

Among 157 high-risk women, breast density was inversely associated with vitamin D intake (odds ratio for third tertile versus first tertile, 0.5; 95% confidence interval, 0.2–1.0). In contrast, intakes above the median level for protein (odds ratio, 3.0; 95% confidence interval, 1.3–6.9) and above the median level for animal protein (odds ratio, 4.3; 95% confidence interval, 1.8–10.3) were associated with higher breast density, but only among women whose family history did not reflect a known familial cancer syndrome or a breast cancer predisposition gene.

Conclusion

For women with a strong family history that was not associated with known cancer syndromes, dietary factors may be associated with breast density, a strong predictor of breast cancer risk. Since women with strong family history are often very motivated to change their lifestyle habits, further studies are needed to confirm whether changes in diet will change the breast density and the subsequent onset of breast cancer in these women.

Sunlight, the vitamin D endocrine system, and their relationships with gynaecologic cancer

Vitamin D has classically been considered an important nutrient, but modern scientific evidence points out that it has a new and more critical role as ubiquitous hormone at the centre of a complex endocrine, paracrine, and autocrine system involved in maintaining general health. Vitamin D is found in small quantities in food; however, it is also produced by the skin when exposed to certain intensities of ultraviolet light. Substantial epidemiological and clinical data suggest a link between low levels of vitamin D and an increased risk of a number of female specific cancers. Different types of cancer cells present vitamin D receptors and the enzymatic system involved in both vitamin D synthesis and inhibition. Sustained low levels of its precursor are responsible for alterations in vitamin D tissue and cell production and metabolism. The active form of vitamin D, 1,25(OH)2D3, can induce differentiation, inhibit proliferation, and modulate immune responsiveness of breast and a wide variety of female genital cell types. Vitamin D effects have been observed on expression of cell cycle regulators, growth factors and their receptors, apoptotic machinery, metastatic potential, and angiogenesis; all of which have some effect on hyperproliferative conditions. However, vitamin D blood levels may not be representative of the local metabolic alterations during carcinogenesis. Clinical studies support the recommendation to increase vitamin D levels to a normal range in order to prevent the tissue disorders related to hypovitaminosis D which are thought to be involved in the initiation and progression of cancer.

Vitamin D and prevention of breast cancer

Epidemiologic data have demonstrated that breast cancer incidence is inversely correlated with indices of vitamin D status, including ultraviolet exposure, which enhances epidermal vitamin D synthesis. The vitamin D receptor (VDR) is expressed in mammary epithelial cells, suggesting that vitamin D may directly influence sensitivity of the gland to transformation. Consistent with this concept, in vitro studies have demonstrated that the VDR ligand, 1,25-dihydroxyvitamin D (1, 25D), exerts negative growth regulatory effects on mammary epithelial cells that contribute to maintenance of the differentiated phenotype. Furthermore, deletion of the VDR gene in mice alters the balance between proliferation and apoptosis in the mammary gland, which ultimately enhances its susceptibility to carcinogenesis. In addition, dietary supplementation with vitamin D, or chronic treatment with synthetic VDR agonists, reduces the incidence of carcinogen-induced mammary tumors in rodents. Collectively, these observations have reinforced the need to further define the human requirement for vitamin D and the molecular actions of the VDR in relation to prevention of breast cancer.