Premenopausal endogenous steroid hormones and breast cancer risk: results from the Nurses' Health Study II

Androgen receptor: Structure, signaling, function and potential drug discovery biomarker in different breast cancer subtypes

The Androgen Receptor (AR) is emerging as an important factor in the pathogenesis of breast cancer (BC), which is the most common malignancy worldwide. >70 % of AR expression in primary and metastatic breast tumors has been observed which suggests that AR may be a new marker and a potential therapeutic target among AR-positive BC patients. Biological insight into AR-positive breast cancer reveals that AR may cross-talk with several vital signaling pathways, including key molecules and receptors. Downstream signaling of AR might also affect many clinically important pathways that are emerging as clinical targets in BC. AR exhibits different behaviors depending on the breast cancer molecular subtype. Preliminary clinical research using AR-targeted drugs, which have already been FDA-approved for prostate cancer (PC), has given promising results for AR-positive breast cancer patients. However, since AR positivity's prognostic and predictive value remains uncertain, it is difficult to identify and stratify patients who would benefit from AR-targeted therapies alone. Thus, the need of the hour is to target the androgen receptor as a monotherapy or in combination with other conventional therapies which has proven to be an effective clinical strategy for the treatment of prostate cancer patients, and these therapeutic strategies are increasingly being investigated in breast cancer. Therefore, in this manuscript, we review the role of AR in various cellular processes that promote tumorigenesis and aggressiveness, in different subtypes of breast cancer, as well as discuss ongoing efforts to target AR for the more effective treatment and prevention of breast cancer.

Lack of evidence that progesterone in ovulatory cycles causes breast cancer

A recent Perspective article asserted that progesterone secretion during ovulatory cycles is the cause of breast cancer. However, we challenge most of the evidence developed in this publication. First, there is a lack of evidence that progesterone is mutagenic for breast cells. Cause of a cancer should mean initiation by mutation, as opposed to promotion. Second, subclinical ovulatory disturbances occur rather frequently in normal-length menstrual cycles. Third, the authors attribute a potential carcinogenic effect to progesterone secreted during menstrual cycles but not to progesterone during pregnancy. They did not discuss breast cancer evidence from progesterone/progestin therapeutics. They argue that in genetic primary amenorrhea, a hypothetic lower risk of breast cancer could be due to the lack of progesterone, despite the progesterone/progestin in hormone replacements these women receive. Fourth, they advocate a regulatory effect of progesterone on several genes potentially involved in cancer genesis. In particular, they attribute a lower risk of breast cancer in women with Mayer-Rokitansky-Küster-Hauser syndrome to a defect in the progesterone-stimulated Wnt4 gene. However, this defect is only present in a small subset. Thus, the postulated progesterone breast cancer risk is unconvincing, which we discuss point by point in this commentary.

Germline Mutations in 12 Genes and Risk of Ovarian Cancer in Three Population-Based Cohorts

BACKGROUND

With the widespread use of multigene panel genetic testing, population-based studies are necessary to accurately assess penetrance in unselected individuals. We evaluated the prevalence of germline pathogenic or likely pathogenic variants (mutations) in 12 cancer-predisposition genes and associations with ovarian cancer risk in three population-based prospective studies [Nurses' Health Study (NHS), NHSII, Cancer Prevention Study II].

METHODS

We included women with epithelial ovarian or peritoneal cancer (n = 776) and controls who were alive and had at least one intact ovary at the time of the matched case diagnosis (n = 1,509). Germline DNA was sequenced for mutations in 12 genes. Conditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) for ovarian cancer risk by mutation status.

RESULTS

The mutation frequency across all 12 genes was 11.2% in cases and 3.3% in controls (P < 0.0001). BRCA1 and BRCA2 were the most frequently mutated (3.5% and 3.8% of cases and 0.3% and 0.5% of controls, respectively) and were associated with increased ovarian cancer risk [OR, BRCA1 = 12.38; 95% confidence interval (CI) = 4.72-32.45; OR, BRCA2 = 9.18; 95% CI = 3.98-21.15]. Mutation frequencies for the other genes were ≤1.0% and only PALB2 was significantly associated with risk (OR = 5.79; 95% CI = 1.09-30.83). There was no difference in survival for women with a BRCA germline mutation versus no mutation.

CONCLUSIONS

Further research is needed to better understand the role of other mutations in ovarian cancer among unselected populations.

IMPACT

Our data support guidelines for germline genetic testing for BRCA1 and BRCA2 among women diagnosed with epithelial ovarian cancer; testing for PALB2 may be warranted.

The impact of obesity and adipokines on breast and gynecologic malignancies

The link between obesity and multiple disease comorbidities is well established. In 2003, Calle and colleagues presented the relationship between obesity and several cancer types, including breast, ovarian, and endometrial malignancies. Nearly, 20% of cancer-related deaths in females can be accounted for by obesity. Identifying obesity as a risk factor for cancer led to a focus on the role of fat-secreted cytokines, known as adipokines, on carcinogenesis and tumor progression. Early studies indicated that the adipokine leptin increases cell proliferation, invasion, and inhibition of apoptosis in multiple cancer types. As a greater appreciation of the obesity-cancer link has amassed, we now know that additional adipokines can impact tumorigenesis. A deeper understanding of the adipokine-activated signaling in cancer may identify new treatment strategies irrespective of obesity. Moreover, adipokines may serve as disease biomarkers, harnessing the potential of obesity-associated factors to serve as indicators of treatment response and disease prognosis. As studies investigating obesity and women's cancers continue to expand, it has become evident that breast, ovarian, and uterine cancers are distinctly impacted by adipokines. While complex, these distinct interactions may provide insight into cancer progression in these organs and new opportunities for targeted therapies. This review aims to organize and present the literature from the last 5 years investigating the mechanisms and implications of adipokine signaling in breast, endometrial, and ovarian cancers with a special focus on leptin and adiponectin.

A Study on Clinico-Pathological Profile of Breast Cancer Patients and Their Correlation With Uterine Fibroids Using Hormone Level and Receptor Status Assessment

Purpose:

To study the clinico-pathological profile of breast cancer patients and the prevalence of uterine fibroids in them, their hormonal levels and hormone receptor status.

Patients and methods:

52 patients with breast cancer who attended AIIMS Bhopal from November 2018 to January 2020 were selected, with their clinical details, triple assessment and other investigations for further management being performed and recorded. The presence of uterine fibroids was assessed using ultrasound of the abdomen, and for patients who had undergone hysterectomy, previous medical records were examined to ascertain the history of uterine fibroids. Serum levels of estrogen and progesterone were assessed using chemi-luminescent micro-particle immune assay (CMIA).

Results:

The mean age of patients was 50.35 ± 10.87 years. 36.54% of our patients had uterine fibroids, of whom 15.38% had undergone hysterectomy for the same, and 21.15% was detected on ultrasound of the abdomen during evaluation. Among patients with uterine fibroids, 84.2% were hormone receptor-positive, while in patients without uterine fibroids, only 57.6% had positive receptors. (P = 0.049). Among premenopausal patients, there was a statistically significant difference in serum progesterone values between patients with and without uterine fibroids.

Conclusion:

The prevalence of uterine fibroids in our study group of breast cancer patients was found to be high. The role of estrogen and progesterone in the pathophysiology of both diseases and the common risk factors involved may biologically explain this finding. Breast cancer and other estrogen associated disorders may hold future research prospects.

Functions of dehydroepiandrosterone in relation to breast cancer

Although DHEA sulfate (DS) is the most abundant steroid in the circulation, breast fluid contains an approximately 80-fold greater concentration than serum. Transport of DS into cells requires organic anion transporting polypeptides (OATPs), which are specific for cell type, cell location, and substrate, but may have a broader specificity for housekeeping functions. Specific classes, which may be modified by soluble factors including neutral steroids, have been identified in the breast. After transport, DS may be cleaved to DHEA by ubiquitous sulfatases, which may be modified by the cell milieu, or DHEA may enter by diffusion. Synthesis from cholesterol does not occur because CYP17B12 and cytochrome b5 are lacking in breast tissues. Case-control studies reveal a positive association of serum DS with risk of breast cancer. The association is even greater with DHEA, particularly in postmenopausal women with HR + invasive tumors. Metabolites of DHEA, androstenedione and testosterone, are associated with breast cancer but DHEA is likely to have an independent role as well. Mechanisms by which DHEA may promote breast cancer relate to its effect in increasing circulating IGF-I, by inhibiting the suppressive effect of glucocorticoids, and by promoting retention of pre-adipocytes with aromatase activity. In addition, DHEA may interact with the G-protein coupled receptor GPER for stimulation of miR-21 and subsequent activation of the MAPK pathway. DHEA also has antitumor properties that relate to stimulation of immunity, suppression of inflammation, and elevation of adipose tissue adiponectin synthesis. The net effect may depend on the which factors predominate.

The Association Between HIV Status, Estradiol, and Sex Hormone Binding Globulin Among Premenopausal Women in the Women's Interagency HIV Study

Background: Characterizing estradiol among women with HIV may have implications for breast cancer and cardiovascular disease risk but has not been adequately explored. We quantified differences in total (E2), free (FE2) estradiol, and sex hormone binding globulin (SHBG) by HIV and viral suppression status. Methods: Women from a substudy (2003-2006) within the Women's Interagency HIV Study (IRB approved at each participating site) were included if they reported: a period in the last six months, were not pregnant/breastfeeding, no oophorectomy, and no exogenous hormone use in the prior year. Serum was collected on days 2-4 of the menstrual cycle. We assessed differences in biomarkers at 25th, 50th, and 75th percentiles by HIV and viral suppression status using weighted quantile regression. Results: Among 643 women (68% with HIV) median age was 37 years. All E2 percentiles were significantly (p < 0.05) lower in women with suppressed viral load versus women without HIV (4-10 pg/mL). The 25th and 50th percentile of E2 were 4-5 pg/mL lower in women with unsuppressed viral load compared to women without HIV (p < 0.05). The 25th and 50th percentile of SHBG was significantly higher in women with unsuppressed viral load compared to women without HIV (10 and 12 nmol/L, respectively). There were no consistent differences in estradiol or SHBG by suppression status. Conclusions: There were no differences in FE2 but significantly lower E2 and higher SHBG among women with HIV versus without HIV. Further research is merited in a large contemporary sample to clarify the clinical implications of these findings.

Linking Physical Activity to Breast Cancer via Sex Steroid Hormones, Part 2: The Effect of Sex Steroid Hormones on Breast Cancer Risk

We undertook a systematic review and appraised the evidence for an effect of circulating sex steroid hormones and sex hormone-binding globulin (SHBG) on breast cancer risk in pre- and postmenopausal women. Systematic searches identified prospective studies relevant to this review. Meta-analyses estimated breast cancer risk for women with the highest compared with the lowest level of sex hormones, and the DRMETA Stata package was used to graphically represent the shape of these associations. The ROBINS-E tool assessed risk of bias, and the GRADE system appraised the strength of evidence. In premenopausal women, there was little evidence that estrogens, progesterone, or SHBG were associated with breast cancer risk, whereas androgens showed a positive association. In postmenopausal women, higher estrogens and androgens were associated with an increase in breast cancer risk, whereas higher SHBG was inversely associated with risk. The strength of the evidence quality ranged from low to high for each hormone. Dose-response relationships between sex steroid hormone concentrations and breast cancer risk were most notable for postmenopausal women. These data support the plausibility of a role for sex steroid hormones in mediating the causal relationship between physical activity and the risk of breast cancer.See related reviews by Lynch et al., p. 11 and Swain et al., p. 16.

Obesity, metabolic syndrome, and cancer: pathophysiological and therapeutic associations

Overweight, obesity, and metabolic syndrome (MetS) have become epidemic conditions affecting 39%, 13%, and 20% of the population respectively. The aim of this article is to review the literature on the association of obesity and MetS with the risk of cancer. We also explore the effect of lifestyle modifications, such as diet, physical activity, and antidiabetic medications, on cancer incidence. Increased body mass index (BMI) has been associated with a multitude of site-specific cancers, reaching relative risk (RR) 1.54 [95% confidence interval (CI) 1.47-1.61] per 5 unit increase for endometrial cancer, as well as with overall cancer risk (RR 1.03, 95% CI 1.02-1.05). Central adiposity measured by waist circumference or waist-to-hip ratio has been suggested as a stronger predictor than BMI for several cancers, such as colorectal cancer. Metabolic Syndrome has been consistently and positively associated with the risk of very common cancers like colorectal (RR 1.34, 95% CI 1.24-1.44), endometrial (RR 1.62, 95% CI 1.26-2.07) and postmenopausal breast cancer (RR 2.01, 95% CI 1.55-2.60). Hyperglycemia and subsequently T2DM have been also shown to increase the risk of cancer. Nevertheless, these risk factors are modifiable and therefore implementing lifestyle modifications could prevent an important number of cancer cases. Adherence to cancer prevention guidelines, including maintaining a healthy weight, having regular physical exercise (RR 0.58-0.90 for different cite specific cancers) and following a healthy dietary pattern (RR 0.74-0.94 for different cite specific cancers) have a protective effect on the risk of cancer. The strength of this review is the presentation of the best evidence, as the data derive mainly from meta-analyses. Public health policies should focus on the modification of risk factors and future research is needed to reveal the pathophysiological links between these risk factors and cancer to develop more efficient prevention and treatment strategies.

Pre-Menopausal Women With Breast Cancers Having High AR/ER Ratios in the Context of Higher Circulating Testosterone Tend to Have Poorer Outcomes

Purpose

Women with breast tumors with higher expression of AR are in general known to have better survival outcomes while a high AR/ER ratio is associated with poor outcomes in hormone receptor positive breast cancers mostly in post menopausal women. We have evaluated the AR/ER ratio in the context of circulating androgens specifically in patients younger than 50 years most of whom are pre-menopausal and hence have a high estrogenic hormonal milieu.

Methods

Tumor samples from patients 50 years or younger at first diagnosis were chosen from a larger cohort of 270 patients with median follow-up of 72 months. Expression levels of ER and AR proteins were detected by immunohistochemistry (IHC) and the transcript levels by quantitative PCR. Ciculating levels of total testosterone were estimated from serum samples. A ratio of AR/ER was derived using the transcript levels, and tumors were dichotomized into high and low ratio groups based on the third quartile value. Survival and the prognostic significance of the ratio was compared between the low and high ratio groups in all tumors and also within ER positive tumors. Results were further validated in external datasets (TCGA and METABRIC).

Results

Eighty-eight (32%) patients were ≤50 years, with 22 having high AR/ER ratio calculated using the transcript levels. Circulating levels of total testosterone were higher in women whose tumors had a high AR/ER ratio (p = 0.02). Tumors with high AR/ER ratio had significantly poorer disease-free survival than those with low AR/ER ratio [HR-2.6 (95% CI-1.02-6.59) p = 0.04]. Evaluation of tumors with high AR/ER ratio within ER positive tumors alone reconfirmed the prognostic relevance of the high AR/ER ratio with a significant hazard ratio of 4.6 (95% CI-1.35-15.37, p = 0.01). Similar trends were observed in the TCGA and METABRIC dataset.

Conclusion

Our data in pre-menopausal women with breast cancer suggest that it is not merely the presence or absence of AR expression but the relative activity of ER, as well as the hormonal milieu of the patient that determine clinical outcomes, indicating that both context and interactions ultimately influence tumor behavior.

The impact of CYP19A1 variants and haplotypes on breast cancer risk, clinicopathological features and prognosis

Background

Different genetic variants in hormone‐regulating pathways have been identified to influence the risk of breast cancer. This study aimed to evaluate the association of CYP19A1 rs10046 and rs700519 polymorphisms with the risk, clinicopathological factors and prognosis of breast cancer.

Methods

In a case‐control study, rs10046 and rs700519 polymorphisms were genotyped using ARMS‐PCR and high‐resolution melting (HRM), respectively, in a total of 702 females. Statistical analysis and evaluation of haplotypes and linkage disequilibrium were performed using SPSS v16, PHASE and 2LD.

Results

Although no association of rs700519 with breast cancer was observed, rs10046 in different genetic models as well as C‐C/C‐T and C‐C/C‐C diplotypes, revealed the association with the risk of breast cancer (p < 0.05). Moreover, the rs700519‐C allele was shown to be associated with longer overall survival. In contrast, the T‐T haplotype conferred s a shorter overall survival. rs700519‐C allele was also significantly associated with menarche age.

Conclusion

Based on the identified independent association between CYP19A1 diplotypes and rs700519‐C allele with the risk and prognosis of the disease, the gene region and its genetic variants may have a diagnostic and prognostic role in breast cancer development. Further confirmation using other variants in this locus can validate these findings.

Body composition and breast cancer risk and treatment: mechanisms and impact

PURPOSE

The purpose of this review is to clarify the association of body composition with breast cancer risk and treatment, including physiological mechanisms, and to elucidate strategies for overcoming unfavorable body composition changes that relate to breast cancer progression.

METHODS

We have summarized updated knowledge regarding the mechanism of the negative association of altered body composition with breast cancer risk and treatment. We also review strategies for reversing unfavorable body composition based on the latest clinical trial results.

RESULTS

Body composition changes in patients with breast cancer typically occur during menopause or as a result of chemotherapy or endocrine therapy. Dysfunction of visceral adipose tissue (VAT) in the setting of obesity underlies insulin resistance and chronic inflammation, which can lead to breast cancer development and progression. Insulin resistance and chronic inflammation are also observed in patients with breast cancer who have sarcopenia or sarcopenic obesity. Nutritional support and a personalized exercise program are the fundamental interventions for reversing unfavorable body composition. Other interventions that have been explored in specific situations include metformin, testosterone, emerging agents that directly target the adipocyte microenvironment, and bariatric surgery.

CONCLUSIONS

A better understanding of the biology of body composition phenotypes is key to determining the best intervention program for patients with breast cancer.

Erythrocyte membrane fatty acids and breast cancer risk by tumor tissue expression of immuno-inflammatory markers and fatty acid synthase: a nested case-control study

BACKGROUND

Previous studies of fatty acids and breast cancer risk have shown mixed results, which may be due in part to tumor heterogeneity. Prior research has also illustrated an important role of specific fatty acids in immune regulation, T cell function, and inflammation, indicating that the effects of specific fatty acids on breast cancer risk may vary by tumor expression of immuno-inflammatory markers. We therefore aimed to evaluate the relationships between prediagnostic erythrocyte membrane fatty acids and breast cancer risk by tumor tissue expression of immuno-inflammatory markers (CD4, CD8, CD20, CD163, COX-2) and fatty acid synthase (FAS).

METHODS

We conducted a matched case-control study nested within the Nurses' Health Study II (n = 235 cases and 235 controls). Blood samples were collected from 1996 to 1999. Tumor tissue blocks were collected for cases diagnosed after blood collection and through 2006. Unconditional nominal polytomous logistic regression adjusted for matching factors and potential confounders was used to assess whether associations between fatty acids and breast cancer risk varied by tumor expression subtype, ascertained via immunohistochemistry. Odds ratios (OR) and 95% confidence intervals (CI) were estimated separately by tumor expression subtype using unconditional logistic regression.

RESULTS

Associations between fatty acids and breast cancer risk did not vary substantially by tumor CD4, CD20, CD163, or COX-2. However, n-3 polyunsaturated fatty acids (PUFAs) were inversely associated with CD8^low but not CD8^high cancers (CD8^low OR_{T3 vs T1} = 0.45, 95% CI 0.23-0.87, P_trend = 0.02; CD8^high OR_{T3 vs T1} = 1.19, 95% CI 0.62-2.26, P_trend = 0.62; P_het = 0.04). n-6 PUFAs were suggestively inversely associated with CD8^high but not CD8^low cancers (CD8^high OR_{T3 vs T1} = 0.61, 95% CI 0.32-1.14, P_trend = 0.11; CD8^low OR_{T3 vs T1} = 1.63, 95% CI 0.87-3.04, P_trend = 0.12; P_het = 0.02). Trans fatty acids were positively associated with FAS^high but not FAS^low tumors (FAS^high OR_{T3 vs T1} = 2.94, 95% CI 1.46-5.91, P_trend = 0.002; FAS^low OR_{T3 vs T1} = 0.99, 95% CI 0.52-1.92, P_trend = 0.97; P_het = 0.01).

CONCLUSION

Results indicate that the effects of n-3 PUFAs, n-6 PUFAs, and trans fatty acids on breast cancer risk may vary by tumor tissue expression subtypes. Findings suggest potential immuno-modulatory and FAS-mediated mechanisms.

Premenopausal Plasma Osteoprotegerin and Breast Cancer Risk: A Case-Control Analysis Nested within the Nurses' Health Study II

BACKGROUND

Emerging evidence supports a role of the receptor activator of NF-κB (RANK) pathway in normal mammary gland development and breast carcinogenesis. Osteoprotegerin (OPG) is the endogenous decoy receptor for RANK-ligand (RANKL), which inhibits RANK-signaling. Whether OPG may be a biomarker of breast cancer risk remains unclear.

METHODS

We evaluated the association between plasma OPG and breast cancer risk in a case (n = 297)-control (n = 297) study nested within the Nurses' Health Study II. Cases were women who were cancer-free and premenopausal at blood collection who developed invasive breast cancer. OPG was quantified using an ELISA. Conditional logistic regression was used to estimate multivariable odds ratios (OR) and 95% confidence intervals (CI) for the association between OPG levels and breast cancer risk, adjusting for potential confounders. Unconditional logistic regression, additionally adjusting for matching factors, was used for stratified analyses.

RESULTS

Overall, there was no substantial evidence for an association between plasma OPG levels and breast cancer risk, although the point estimate for the highest (vs. lowest) quartile was below 1 (OR = 0.78; 95% CI, 0.46-1.33; P _trend = 0.30). There was no evidence of heterogeneity by various reproductive, hormonal, or tumor characteristics, including hormone receptor status and grade (all P _{heterogeneity} ≥ 0.17).

CONCLUSIONS

Findings from this prospective study do not provide substantial evidence for an association between circulating OPG and breast cancer risk among premenopausal women; however, we were underpowered in stratified analyses.

IMPACT

Results do not provide strong evidence for OPG as a potential biomarker of breast cancer risk among premenopausal women.

Fiber consumption and breast cancer incidence: A systematic review and meta-analysis of prospective studies

BACKGROUND

Associations between fiber intake and breast cancer risk have been evaluated in prospective studies, but overall, the evidence is inconsistent. The authors performed a systematic review and meta-analysis of prospective studies to investigate the relation between intake of total and types of fiber with breast cancer incidence.

METHODS

The MEDLINE and Excerpta Medica dataBASE (EMBASE) databases were searched through July 2019 for prospective studies that reported on the association between fiber consumption and incident breast cancer. The pooled relative risk (RR) and 95% confidence intervals (95% CI) were estimated comparing the highest versus the lowest category of total and types of fiber consumption, using a random-effects meta-analysis.

RESULTS

The authors identified 17 cohort studies, 2 nested case-control studies, and 1 clinical trial study. Total fiber consumption was associated with an 8% lower risk of breast cancer (comparing the highest versus the lowest category, pooled RR, 0.92; 95% CI, 0.88-0.95 [I²  = 12.6%]). Soluble fiber was found to be significantly inversely associated with risk of breast cancer (pooled RR, 0.90 [95% CI, 0.84-0.96; I² = 12.6%]) and insoluble fiber was found to be suggestively inversely associated with risk of breast cancer (pooled RR, 0.93 [95% CI, 0.86-1.00; I² = 33.4%]). Higher total fiber intake was associated with a lower risk of both premenopausal and postmenopausal breast cancers (pooled RR, 0.82 [95% CI, 0.67-0.99; I²  = 35.2%] and pooled RR, 0.91 [95% CI, 0.88-0.95; I²  = 0.0%], respectively). Furthermore, the authors observed a nonsignificant inverse association between intake of total fiber and risk of both estrogen and progesterone receptor-positive and estrogen and progesterone receptor-negative breast cancers.

CONCLUSIONS

A random-effects meta-analysis of prospective observational studies demonstrated that high total fiber consumption was associated with a reduced risk of breast cancer. This finding was consistent for soluble fiber as well as for women with premenopausal and postmenopausal breast cancer.

Progesterone and Breast Cancer

Synthetic progestogens (progestins) have been linked to increased breast cancer risk; however, the role of endogenous progesterone in breast physiology and carcinogenesis is less clearly defined. Mechanistic studies using cell culture, tissue culture, and preclinical models implicate progesterone in breast carcinogenesis. In contrast, limited epidemiologic data generally do not show an association of circulating progesterone levels with risk, and it is unclear whether this reflects methodologic limitations or a truly null relationship. Challenges related to defining the role of progesterone in breast physiology and neoplasia include: complex interactions with estrogens and other hormones (eg, androgens, prolactin, etc.), accounting for timing of blood collections for hormone measurements among cycling women, and limitations of assays to measure progesterone metabolites in blood and progesterone receptor isotypes (PRs) in tissues. Separating the individual effects of estrogens and progesterone is further complicated by the partial dependence of PR transcription on estrogen receptor (ER)α-mediated transcriptional events; indeed, interpreting the integrated interaction of the hormones may be more essential than isolating independent effects. Further, many of the actions of both estrogens and progesterone, particularly in "normal" breast tissues, are driven by paracrine mechanisms in which ligand binding to receptor-positive cells evokes secretion of factors that influence cell division of neighboring receptor-negative cells. Accordingly, blood and tissue levels may differ, and the latter are challenging to measure. Given conflicting data related to the potential role of progesterone in breast cancer etiology and interest in blocking progesterone action to prevent or treat breast cancer, we provide a review of the evidence that links progesterone to breast cancer risk and suggest future directions for filling current gaps in our knowledge.

Inclusion of Endogenous Plasma Dehydroepiandrosterone Sulfate and Mammographic Density in Risk Prediction Models for Breast Cancer

BACKGROUND

Endogenous hormones and mammographic density are risk factors for breast cancer. Joint analyses of the two may improve the ability to identify high-risk women.

METHODS

This study within the KARMA cohort included prediagnostic measures of plasma hormone levels of dehydroepiandrosterone (DHEA), its sulfate (DHEAS), and mammographic density in 629 cases and 1,223 controls, not using menopausal hormones. We evaluated the area under the receiver-operating curve (AUC) for risk of breast cancer by adding DHEA, DHEAS, and mammographic density to the Gail or Tyrer-Cuzick 5-year risk scores or the CAD2Y 2-year risk score.

RESULTS

DHEAS and percentage density were independently and positively associated with breast cancer risk (P = 0.007 and P < 0.001, respectively) for postmenopausal, but not premenopausal, women. No significant association was seen for DHEA. In postmenopausal women, those in the highest tertiles of both DHEAS and density were at greatest risk of breast cancer (OR, 3.5; 95% confidence interval, 1.9-6.3) compared with the lowest tertiles. Adding DHEAS significantly improved the AUC for the Gail (+2.1 units, P = 0.008) and Tyrer-Cuzick (+1.3 units, P = 0.007) risk models. Adding DHEAS to the Gail and Tyrer-Cuzick models already including mammographic density further increased the AUC by 1.2 units (P = 0.006) and 0.4 units (P = 0.007), respectively, compared with only including density.

CONCLUSIONS

DHEAS and mammographic density are independent risk factors for breast cancer and improve risk discrimination for postmenopausal breast cancer.

IMPACT

Combining DHEAS and mammographic density could help identify women at high risk who may benefit from individualized breast cancer screening and/or preventive measures among postmenopausal women.

Breast cancer risk prediction in women aged 35-50 years: impact of including sex hormone concentrations in the Gail model

Background

Models that accurately predict risk of breast cancer are needed to help younger women make decisions about when to begin screening. Premenopausal concentrations of circulating anti-Müllerian hormone (AMH), a biomarker of ovarian reserve, and testosterone have been positively associated with breast cancer risk in prospective studies. We assessed whether adding AMH and/or testosterone to the Gail model improves its prediction performance for women aged 35–50.

Methods

In a nested case-control study including ten prospective cohorts (1762 invasive cases/1890 matched controls) with pre-diagnostic serum/plasma samples, we estimated relative risks (RR) for the biomarkers and Gail risk factors using conditional logistic regression and random-effects meta-analysis. Absolute risk models were developed using these RR estimates, attributable risk fractions calculated using the distributions of the risk factors in the cases from the consortium, and population-based incidence and mortality rates. The area under the receiver operating characteristic curve (AUC) was used to compare the discriminatory accuracy of the models with and without biomarkers.

Results

The AUC for invasive breast cancer including only the Gail risk factor variables was 55.3 (95% CI 53.4, 57.1). The AUC increased moderately with the addition of AMH (AUC 57.6, 95% CI 55.7, 59.5), testosterone (AUC 56.2, 95% CI 54.4, 58.1), or both (AUC 58.1, 95% CI 56.2, 59.9). The largest AUC improvement (4.0) was among women without a family history of breast cancer.

Conclusions

AMH and testosterone moderately increase the discriminatory accuracy of the Gail model among women aged 35–50. We observed the largest AUC increase for women without a family history of breast cancer, the group that would benefit most from improved risk prediction because early screening is already recommended for women with a family history.

Electronic supplementary material

The online version of this article (10.1186/s13058-019-1126-z) contains supplementary material, which is available to authorized users.

Comparability of serum, plasma, and urinary estrogen and estrogen metabolite measurements by sex and menopausal status

PURPOSE

The comparability between serum, plasma, and urinary measurements of estrogen metabolites via liquid chromatography-tandem mass spectrometry (LC-MS/MS) has not been largely explored, and it is unclear if urinary LC-MS/MS measurements are suitable surrogates of circulating levels.

METHODS

Serum, plasma (EDTA and heparin), and urinary estrogen/estrogen metabolite levels were measured via LC-MS/MS in paired samples from 64 healthy volunteers (18 men, 20 premenopausal women, 26 postmenopausal women). Geometric means and Spearman correlation coefficients were used to compare individual and combined pathway levels of estrogens/estrogen metabolites across biologic matrices by sex/menopausal status.

RESULTS

Measured concentrations of estrogens/estrogen metabolites across blood matrices were almost identical (percent differences < 4.8%). Parent estrogen concentrations measured in serum and urine were moderately correlated in postmenopausal women (estrone: r = 0.69, estradiol: r = 0.69). Correlations were similar comparing unconjugated serum estradiol to urinary estrone (r = 0.76) and urinary estradiol (r = 0.65) in postmenopausal women but were moderate to low in premenopausal women (r = 0.60, 0.40, respectively)/men (r = 0.33, 0.53, respectively). Comparing metabolite ratios, proportionally higher concentrations of 16-pathway metabolites were measured in urine versus serum across sex/menopausal status groups (e.g., postmenopausal women: 50.3% 16-pathway metabolites/total in urine versus 35.3% in serum).

CONCLUSIONS

There is strong agreement between estrogen/estrogen metabolites measurements in serum, heparin plasma, and EDTA plasma. Individual estrogen metabolite concentrations were moderately correlated between urine and serum, but were not well correlated when evaluating pathway- or relative estrogen concentrations. Differences between serum and urine are likely explained by differences in metabolism and/or excretion.

Association of Body Mass Index and Age With Subsequent Breast Cancer Risk in Premenopausal Women

Importance

The association between increasing body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) and risk of breast cancer is unique in cancer epidemiology in that a crossover effect exists, with risk reduction before and risk increase after menopause. The inverse association with premenopausal breast cancer risk is poorly characterized but might be important in the understanding of breast cancer causation.

Objective

To investigate the association of BMI with premenopausal breast cancer risk, in particular by age at BMI, attained age, risk factors for breast cancer, and tumor characteristics.

Design, Setting, and Participants

This multicenter analysis used pooled individual-level data from 758 592 premenopausal women from 19 prospective cohorts to estimate hazard ratios (HRs) of premenopausal breast cancer in association with BMI from ages 18 through 54 years using Cox proportional hazards regression analysis. Median follow-up was 9.3 years (interquartile range, 4.9-13.5 years) per participant, with 13 082 incident cases of breast cancer. Participants were recruited from January 1, 1963, through December 31, 2013, and data were analyzed from September 1, 2013, through December 31, 2017.

Exposures

Body mass index at ages 18 to 24, 25 to 34, 35 to 44, and 45 to 54 years.

Main Outcomes and Measures

Invasive or in situ premenopausal breast cancer.

Results

Among the 758 592 premenopausal women (median age, 40.6 years; interquartile range, 35.2-45.5 years) included in the analysis, inverse linear associations of BMI with breast cancer risk were found that were stronger for BMI at ages 18 to 24 years (HR per 5 kg/m2 [5.0-U] difference, 0.77; 95% CI, 0.73-0.80) than for BMI at ages 45 to 54 years (HR per 5.0-U difference, 0.88; 95% CI, 0.86-0.91). The inverse associations were observed even among nonoverweight women. There was a 4.2-fold risk gradient between the highest and lowest BMI categories (BMI≥35.0 vs <17.0) at ages 18 to 24 years (HR, 0.24; 95% CI, 0.14-0.40). Hazard ratios did not appreciably vary by attained age or between strata of other breast cancer risk factors. Associations were stronger for estrogen receptor-positive and/or progesterone receptor-positive than for hormone receptor-negative breast cancer for BMI at every age group (eg, for BMI at age 18 to 24 years: HR per 5.0-U difference for estrogen receptor-positive and progesterone receptor-positive tumors, 0.76 [95% CI, 0.70-0.81] vs hormone receptor-negative tumors, 0.85 [95% CI: 0.76-0.95]); BMI at ages 25 to 54 years was not consistently associated with triple-negative or hormone receptor-negative breast cancer overall.

Conclusions and Relevance

The results of this study suggest that increased adiposity is associated with a reduced risk of premenopausal breast cancer at a greater magnitude than previously shown and across the entire distribution of BMI. The strongest associations of risk were observed for BMI in early adulthood. Understanding the biological mechanisms underlying these associations could have important preventive potential.

Addition of a polygenic risk score, mammographic density, and endogenous hormones to existing breast cancer risk prediction models: A nested case-control study

BACKGROUND

No prior study to our knowledge has examined the joint contribution of a polygenic risk score (PRS), mammographic density (MD), and postmenopausal endogenous hormone levels-all well-confirmed risk factors for invasive breast cancer-to existing breast cancer risk prediction models.

METHODS AND FINDINGS

We conducted a nested case-control study within the prospective Nurses' Health Study and Nurses' Health Study II including 4,006 cases and 7,874 controls ages 34-70 years up to 1 June 2010. We added a breast cancer PRS using 67 single nucleotide polymorphisms, MD, and circulating testosterone, estrone sulfate, and prolactin levels to existing risk models. We calculated area under the curve (AUC), controlling for age and stratified by menopausal status, for the 5-year absolute risk of invasive breast cancer. We estimated the population distribution of 5-year predicted risks for models with and without biomarkers. For the Gail model, the AUC improved (p-values < 0.001) from 55.9 to 64.1 (8.2 units) in premenopausal women (Gail + PRS + MD), from 55.5 to 66.0 (10.5 units) in postmenopausal women not using hormone therapy (HT) (Gail + PRS + MD + all hormones), and from 58.0 to 64.9 (6.9 units) in postmenopausal women using HT (Gail + PRS + MD + prolactin). For the Rosner-Colditz model, the corresponding AUCs improved (p-values < 0.001) by 5.7, 6.2, and 6.5 units. For estrogen-receptor-positive tumors, among postmenopausal women not using HT, the AUCs improved (p-values < 0.001) by 14.3 units for the Gail model and 7.3 units for the Rosner-Colditz model. Additionally, the percentage of 50-year-old women predicted to be at more than twice 5-year average risk (≥2.27%) was 0.2% for the Gail model alone and 6.6% for the Gail + PRS + MD + all hormones model. Limitations of our study included the limited racial/ethnic diversity of our cohort, and that general population exposure distributions were unavailable for some risk factors.

CONCLUSIONS

In this study, the addition of PRS, MD, and endogenous hormones substantially improved existing breast cancer risk prediction models. Further studies will be needed to confirm these findings and to determine whether improved risk prediction models have practical value in identifying women at higher risk who would most benefit from chemoprevention, screening, and other risk-reducing strategies.

Chemoprevention of LA7-Induced Mammary Tumor Growth by SM6Met, a Well-Characterized Cyclopia Extract

Breast cancer (BC) is the leading cause of cancer-related deaths in women. Chemoprevention of BC by using plant extracts is gaining attention. SM6Met, a well-characterized extract of Cyclopia subternata with reported selective estrogen receptor subtype activity, has shown tumor suppressive effects in a chemically induced BC model in rats, which is known to be estrogen responsive. However, there is no information on the estrogen sensitivity of the relatively new orthotopic model of LA7 cell-induced mammary tumors. In the present study, the potential chemopreventative and side-effect profile of SM6Met on LA7 cell-induced tumor growth was evaluated, as was the effects of 17β-estradiol and standard-of-care (SOC) endocrine therapies, such as tamoxifen (TAM), letrozole (LET), and fulvestrant (FUL). Tumor growth was observed in the tumor-vehicle control group until day 10 post tumor induction, which declined afterward on days 12-14. SM6Met suppressed tumor growth to the same extent as TAM, while LET, but not FUL, also showed substantial anti-tumor effects. Short-term 17β-estradiol treatment reduced tumor volume on days prior to day 10, whereas tumor promoting effects were observed during long-term treatment, which was especially evident at later time points. Marked elevation in serum markers of liver injury, which was further supported by histological evaluation, was observed in the vehicle-treated tumor control, TAM, LET, and long-term 17β-estradiol treatment groups. Alterations in the lipid profiles were also observed in the 17β-estradiol treatment groups. In contrast, SM6Met did not augment the increase in serum levels of liver injury biomarkers caused by tumor induction and no effect was observed on lipid profiles. In summary, the results from the current study demonstrate the chemopreventative effect of SM6Met on mammary tumor growth, which was comparable to that of TAM, without eliciting the negative side-effects observed with this SOC endocrine therapy. Furthermore, the results of this study also showed some responsiveness of LA7-induced tumors to estrogen and SOC endocrine therapies. Thus, this model may be useful in evaluating potential endocrine therapies for hormone responsive BC.

Circulating anti-Müllerian hormone and breast cancer risk: A study in ten prospective cohorts

A strong positive association has been observed between circulating anti-Müllerian hormone (AMH), a biomarker of ovarian reserve, and breast cancer risk in three prospective studies. Confirming this association is important because of the paucity of biomarkers of breast cancer risk in premenopausal women. We conducted a consortium study including ten prospective cohorts that had collected blood from premenopausal women. A nested case-control design was implemented within each cohort. A total of 2,835 invasive (80%) and in situ (20%) breast cancer cases were individually matched to controls (n = 3,122) on age at blood donation. AMH was measured using a high sensitivity enzyme-linked immunoabsorbent assay. Conditional logistic regression was applied to the aggregated dataset. There was a statistically significant trend of increasing breast cancer risk with increasing AMH concentration (ptrend across quartiles <0.0001) after adjusting for breast cancer risk factors. The odds ratio (OR) for breast cancer in the top vs. bottom quartile of AMH was 1.60 (95% CI = 1.31-1.94). Though the test for interaction was not statistically significant (pinteraction  = 0.15), the trend was statistically significant only for tumors positive for both estrogen receptor (ER) and progesterone receptor (PR): ER+/PR+: ORQ4-Q1  = 1.96, 95% CI = 1.46-2.64, ptrend <0.0001; ER+/PR-: ORQ4-Q1  = 0.82, 95% CI = 0.40-1.68, ptrend  = 0.51; ER-/PR+: ORQ4-Q1  = 3.23, 95% CI = 0.48-21.9, ptrend  = 0.26; ER-/PR-: ORQ4-Q1  = 1.15, 95% CI = 0.63-2.09, ptrend  = 0.60. The association was observed for both pre- (ORQ4-Q1 = 1.35, 95% CI = 1.05-1.73) and post-menopausal (ORQ4-Q1  = 1.61, 95% CI = 1.03-2.53) breast cancer (pinteraction  = 0.34). In this large consortium study, we confirmed that AMH is associated with breast cancer risk, with a 60% increase in risk for women in the top vs. bottom quartile of AMH.

Anti-Müllerian hormone and risk of ovarian cancer in nine cohorts

Animal and experimental data suggest that anti-Müllerian hormone (AMH) serves as a marker of ovarian reserve and inhibits the growth of ovarian tumors. However, few epidemiologic studies have examined the association between AMH and ovarian cancer risk. We conducted a nested case-control study of 302 ovarian cancer cases and 336 matched controls from nine cohorts. Prediagnostic blood samples of premenopausal women were assayed for AMH using a picoAMH enzyme-linked immunosorbent assay. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using multivariable-adjusted conditional logistic regression. AMH concentration was not associated with overall ovarian cancer risk. The multivariable-adjusted OR (95% CI), comparing the highest to the lowest quartile of AMH, was 0.99 (0.59-1.67) (Ptrend : 0.91). The association did not differ by age at blood draw or oral contraceptive use (all Pheterogeneity : ≥0.26). There also was no evidence for heterogeneity of risk for tumors defined by histologic developmental pathway, stage, and grade, and by age at diagnosis and time between blood draw and diagnosis (all Pheterogeneity : ≥0.39). In conclusion, this analysis of mostly late premenopausal women from nine cohorts does not support the hypothesized inverse association between prediagnostic circulating levels of AMH and risk of ovarian cancer.

Circulating Hormones and Mammographic Density in Premenopausal Women

Prior research suggests that several endogenous hormones in premenopausal women are associated with breast cancer risk; however, few studies have evaluated associations of endogenous hormones with mammographic density (MD) in premenopausal women. We conducted a cross-sectional study of plasma hormone levels in relation to MD among 634 cancer-free premenopausal women in the Nurses' Health Study II. We measured percent MD from screening mammograms using a computer-assisted method. We assayed estradiol, estrone, and estrone sulfate in blood samples timed in early follicular and mid-luteal phases of the menstrual cycle as well as testosterone, androstenedione, progesterone, dehydroepiandrosterone (DHEA), DHEA sulfate, sex hormone-binding globulin (SHBG), and anti-Müllerian hormone in luteal or untimed samples. We used multivariable linear regression to quantify the association of %MD with quartiles of each hormone, adjusting for age, body mass index, and breast cancer risk factors. Women in the highest quartile of follicular estradiol levels had significantly greater %MD compared to those in the lowest quartile [difference, 6.7 percentage points; 95% confidence interval (CI) 2.2, 11.3; p-trend < 0.001]. Similar associations were observed for follicular free estradiol but not luteal-phase estradiol. Also, women in the top (vs. bottom) quartile of free testosterone had significantly lower %MD (difference, - 4.7; 95% CI - 8.7, - 0.8; p-trend = 0.04). Higher SHBG was significantly associated with higher percent MD (difference, 4.8; 95% CI 1.1, 8.6; p-trend = 0.002). Percent MD was not strongly associated with other measured hormones. Results were similar in analyses that excluded women with anovulatory cycles. Our findings suggest that follicular estradiol and SHBG may play an important role in premenopausal percent MD.

Genetic and environmental factors and serum hormones, and risk of estrogen receptor-positive breast cancer in pre- and postmenopausal Japanese women

Breast cancer incidence in Japanese women has more than tripled over the past two decades. We have previously shown that this marked increase is mostly due to an increase in the estrogen receptor (ER)-positive, HER2-negative subtype. We conducted a case-control study; ER-positive, HER2-negative breast cancer patients who were diagnosed since 2011 and women without disease were recruited. Environmental factors, serum levels of testosterone and 25-hydroxyvitamin D, and common genetic variants reported as predictors of ER-positive breast cancer or found in Asian women were evaluated between patients and controls in pre- and postmenopausal women. To identify important risk predictors, risk prediction models were created by logistic regression models. In premenopausal women, two environmental factors (history of breastfeeding, and history of benign breast disease) and four genetic variants (TOX3-rs3803662, ESR1-rs2046210, 8q24-rs13281615, and SLC4A7-rs4973768) were considered to be risk predictors, whereas three environmental factors (body mass index, history of breastfeeding, and hyperlipidemia), serum levels of testosterone and 25-hydroxyvitamin D, and two genetic variants (TOX3-rs3803662 and ESR1-rs2046210) were identified as risk predictors. Inclusion of common genetic variants and serum hormone measurements as well as environmental factors improved risk assessment models. The decline in the birthrate according to recent changes of lifestyle might be the main cause of the recent notable increase in the incidence of ER-positive breast cancer in Japanese women.

Hormonally up-regulated neu-associated kinase: A novel target for breast cancer progression

Hormonally up-regulated neu-associated Kinase (Hunk) is a protein kinase that was originally identified in the murine mammary gland and has been shown to be highly expressed in Human Epidermal Growth Factor Receptor 2 positive (HER2+/ErbB2+) breast cancer cell lines as well as MMTV-neu derived mammary tumor cell lines. However, the physiological role of Hunk has been largely elusive since its identification. Though Hunk is predicted to be a Serine/Threonine (Ser/Thr) protein kinase with homology to the SNF1/AMPK family of protein kinases, there are no known Hunk substrates that have been identified to date. Recent work demonstrates a role for Hunk in HER2+/ErbB2+ breast cancer progression, including drug resistance to HER2/ErbB2 inhibitors, with Hunk potentially acting downstream of HER2/ErbB2 and the PI3K/Akt pathway. These studies have collectively shown that Hunk plays a vital role in promoting mammary tumorigenesis, as Hunk knockdown via shRNA in xenograft tumor models or crossing MMTV-neu or Pten-deficient genetically engineered mouse models into a Hunk knockout (Hunk-/-) background impairs mammary tumor growth in vivo. Because the majority of HER2+/ErbB2+ breast cancer patients acquire drug resistance to HER2/ErbB2 inhibitors, the characterization of novel drug targets like Hunk that have the potential to simultaneously suppress tumorigenesis and potentially enhance efficacy of current therapeutics is an important facet of drug development. Therefore, work aimed at uncovering specific regulatory functions for Hunk that could contribute to this protein kinase's role in both tumorigenesis and drug resistance will be informative. This review focuses on what is currently known about this under-studied protein kinase, and how targeting Hunk may prove to be a potential therapeutic target for the treatment of breast cancer.

Demographic, lifestyle, and other factors in relation to antimüllerian hormone levels in mostly late premenopausal women

OBJECTIVE

To identify reproductive, lifestyle, hormonal, and other correlates of circulating antimüllerian hormone (AMH) concentrations in mostly late premenopausal women.

DESIGN

Cross-sectional study.

SETTING

Not applicable.

PATIENT(S)

A total of 671 premenopausal women not known to have cancer.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Concentrations of AMH were measured in a single laboratory using the picoAMH ELISA. Multivariable-adjusted median (and interquartile range) AMH concentrations were calculated using quantile regression for several potential correlates.

RESULT(S)

Older women had significantly lower AMH concentrations (≥40 [n = 444] vs. <35 years [n = 64], multivariable-adjusted median 0.73 ng/mL vs. 2.52 ng/mL). Concentrations of AMH were also significantly lower among women with earlier age at menarche (<12 [n = 96] vs. ≥14 years [n = 200]: 0.90 ng/mL vs. 1.12 ng/mL) and among current users of oral contraceptives (n = 27) compared with never or former users (n = 468) (0.36 ng/mL vs. 1.15 ng/mL). Race, body mass index, education, height, smoking status, parity, and menstrual cycle phase were not significantly associated with AMH concentrations. There were no significant associations between AMH concentrations and androgen or sex hormone-binding globulin concentrations or with factors related to blood collection (e.g., sample type, time, season, and year of blood collection).

CONCLUSION(S)

Among premenopausal women, lower AMH concentrations are associated with older age, a younger age at menarche, and currently using oral contraceptives, suggesting these factors are related to a lower number or decreased secretory activity of ovarian follicles.

Dietary Patterns and Plasma Sex Hormones, Prolactin, and Sex Hormone-Binding Globulin in Premenopausal Women

BACKGROUND

Sex hormones are important for breast cancer, but it is unclear whether dietary patterns influence hormone concentrations.

METHODS

Dietary pattern adherence scores for the alternate Mediterranean diet (aMED), Dietary Approaches to Stop Hypertension (DASH), and Alternative Healthy Eating Index (AHEI) were calculated from semiquantitative food frequency questionnaires administered in 1995 and 1999. Premenopausal plasma concentrations of sex hormones were measured in samples collected in 1996 to 1999. We used generalized linear models to calculate geometric mean hormone concentrations across quartiles of dietary pattern scores among 1,990 women in the Nurses' Health Study II.

RESULTS

We did not observe significant associations between sex hormone concentrations and the DASH pattern and only one suggestive association between follicular estrone concentrations and the aMED pattern [top vs. bottom quartile -4.4%, 95% confidence interval (CI), -10.6% to 2.1%; Ptrend = 0.06]. However, women in the top versus bottom quartile of AHEI score had lower concentrations of follicular (-9.1%; 95% CI, -16.1% to -1.4%; Ptrend = 0.04) and luteal (-7.5%; 95% CI, -13.6% to -0.9%; Ptrend = 0.01) estrone, luteal-free (-9.3%; 95% CI, -16.8% to -1.1%; Ptrend = 0.01) and total (-6.7 %; 95% CI, -14.3% to 1.5%; Ptrend = 0.04) estradiol, follicular estradiol (-14.2%; 95% CI, -24.6% to -2.4%; Ptrend = 0.05), and androstenedione (-7.8%; 95% CI, -15.4% to 0.4%; Ptrend = 0.03).

CONCLUSION

Diet quality measured by the AHEI is inversely associated with premenopausal estrogen concentrations. Given that we did not observe similar associations with the aMED or DASH patterns, our findings should be interpreted with caution.

IMPACT

Given the role of estrogens in breast cancer etiology, our findings add to the substantial evidence on the benefits of adhering to a healthy diet. Cancer Epidemiol Biomarkers Prev; 25(5); 791-8. ©2016 AACR.

Plasma Anti-Müllerian Hormone Concentrations and Risk of Breast Cancer among Premenopausal Women in the Nurses' Health Studies

BACKGROUND

Anti-Müllerian hormone (AMH) is a member of the TGFβ family of growth and differentiation factors with a key role in regulating folliculogenesis. In experimental studies, using supraphysiologic concentrations, AMH inhibits breast cancer growth. However, high levels of AMH were associated with increased breast cancer risk in two prior prospective epidemiologic studies.

METHODS

We conducted a nested case-control study of premenopausal plasma AMH and breast cancer risk within the Nurses' Health Study (NHS) and NHSII. In NHS, 32,826 women donated blood samples in 1989-1990; in NHSII, 29,611 women donated samples in 1996-1999. After blood collection and before February 2004 (NHS) or July 2010 (NHSII), 539 cases were diagnosed among women premenopausal at diagnosis, and were matched 1:1 to controls. ORs and 95% confidence intervals (CI) were calculated using unconditional logistic regression, adjusting for matching and breast cancer risk factors.

RESULTS

Higher plasma levels of AMH were associated with increased breast cancer risk (top vs. bottom quintile multivariate OR, 2.20; 95% CI, 1.34-3.63; P trend = 0.001). The association did not vary by invasive versus in situ disease or by estrogen receptor status. Associations were not significantly different by age at blood or diagnosis. Further adjustment for plasma estradiol or testosterone yielded similar results.

CONCLUSIONS

Higher circulating AMH levels are associated with increased breast cancer risk among premenopausal women.

IMPACT

The significant positive association between premenopausal plasma AMH levels and subsequent breast cancer risk before menopause suggests AMH may be useful as a marker of breast cancer risk in younger women. Cancer Epidemiol Biomarkers Prev; 25(5); 854-60. ©2016 AACR.

The controversial role of human chorionic gonadotropin in the development of breast cancer and other types of tumors

INTRODUCTION

Breast cancer is the most often diagnosed tumor of women and one of the leading cause of cancer related death. Due to different known risk factors there are epidemiological differences. Beside genetic disorders and patient's age it is especially the age of the first full-term pregnancy and in this context the pregnancy hormone human chorionic gonadotropin that seems to play an important role.

METHODS

This review is based on a PubMed research in publications of the last 20 years. Only articles in English language were considered.

RESULTS

The effect of human chorionic gonadotropin on development of cancer is controversial. In fact, for breast cancer there is evidence that this hormone has a protective effect against tumorigenesis due the differentiation of the mammary tissue after a full term pregnancy through the downregulation of estrogen receptors.

CONCLUSION

Human chorionic gonadotropin has among promoting pregnancy important controversial functions especially in tumor development. The mechanisms that explain the pro- and anti-carcinogenic effects are not fully understood yet. It seems to have a protective effect on breast cancer through increasing differentiation and hereby decreasing susceptibility of the mammary tissue for toxicants. This knowledge might help developing a preventive agent in the next future that uses the anti-carcinogenic effect of human chorionic gonadotropin and thereby decrease the mortality out of breast cancer.

Cancer and fertility preservation: international recommendations from an expert meeting

In the last years, thanks to the improvement in the prognosis of cancer patients, a growing attention has been given to the fertility issues. International guidelines on fertility preservation in cancer patients recommend that physicians discuss, as early as possible, with all patients of reproductive age their risk of infertility from the disease and/or treatment and their interest in having children after cancer, and help with informed fertility preservation decisions. As recommended by the American Society of Clinical Oncology and the European Society for Medical Oncology, sperm cryopreservation and embryo/oocyte cryopreservation are standard strategies for fertility preservations in male and female patients, respectively; other strategies (e.g. pharmacological protection of the gonads and gonadal tissue cryopreservation) are considered experimental techniques. However, since then, new data have become available, and several issues in this field are still controversial and should be addressed by both patients and their treating physicians.In April 2015, physicians with expertise in the field of fertility preservation in cancer patients from several European countries were invited in Genova (Italy) to participate in a workshop on the topic of "cancer and fertility preservation". A total of ten controversial issues were discussed at the conference. Experts were asked to present an up-to-date review of the literature published on these topics and the presentation of own unpublished data was encouraged. On the basis of the data presented, as well as the expertise of the invited speakers, a total of ten recommendations were discussed and prepared with the aim to help physicians in counseling their young patients interested in fertility preservation.Although there is a great interest in this field, due to the lack of large prospective cohort studies and randomized trials on these topics, the level of evidence is not higher than 3 for most of the recommendations highlighting the need of further research efforts in many areas of this field. The participation to the ongoing registries and prospective studies is crucial to acquire more robust information in order to provide evidence-based recommendations.

The Regulation of Steroid Action by Sulfation and Desulfation

Steroid sulfation and desulfation are fundamental pathways vital for a functional vertebrate endocrine system. After biosynthesis, hydrophobic steroids are sulfated to expedite circulatory transit. Target cells express transmembrane organic anion-transporting polypeptides that facilitate cellular uptake of sulfated steroids. Once intracellular, sulfatases hydrolyze these steroid sulfate esters to their unconjugated, and usually active, forms. Because most steroids can be sulfated, including cholesterol, pregnenolone, dehydroepiandrosterone, and estrone, understanding the function, tissue distribution, and regulation of sulfation and desulfation processes provides significant insights into normal endocrine function. Not surprisingly, dysregulation of these pathways is associated with numerous pathologies, including steroid-dependent cancers, polycystic ovary syndrome, and X-linked ichthyosis. Here we provide a comprehensive examination of our current knowledge of endocrine-related sulfation and desulfation pathways. We describe the interplay between sulfatases and sulfotransferases, showing how their expression and regulation influences steroid action. Furthermore, we address the role that organic anion-transporting polypeptides play in regulating intracellular steroid concentrations and how their expression patterns influence many pathologies, especially cancer. Finally, the recent advances in pharmacologically targeting steroidogenic pathways will be examined.

Breast cancer risk factors

Breast cancer is the most frequently diagnosed neoplastic disease in women around menopause often leading to a significant reduction of these women's ability to function normally in everyday life. The increased breast cancer incidence observed in epidemiological studies in a group of women actively participating in social and professional life implicates the necessity of conducting multidirectional studies in order to identify risk factors associated with the occurrence of this type of neoplasm. Taking the possibility of influencing the neoplastic transformation process in individuals as a criterion, all the risk factors initiating the process can be divided into two groups. The first group would include inherent factors such as age, sex, race, genetic makeup promoting familial occurrence of the neoplastic disease or the occurrence of benign proliferative lesions of the mammary gland. They all constitute independent parameters and do not undergo simple modification in the course of an individual's life. The second group would include extrinsic factors conditioned by lifestyle, diet or long-term medical intervention such as using oral hormonal contraceptives or hormonal replacement therapy and their influence on the neoplastic process may be modified to a certain degree. Identification of modifiable factors may contribute to development of prevention strategies decreasing breast cancer incidence.

Dietary Fat and Fiber Intakes Are Not Associated with Patterns of Urinary Estrogen Metabolites in Premenopausal Women

BACKGROUND

Interindividual differences in the bioavailability of potentially carcinogenic estrogen and estrogen metabolites (EMs) may play a role in the risk of breast cancer.

OBJECTIVE

We examined whether dietary intakes of fiber and fat influence premenopausal EM profiles through effects on estrogen synthesis, metabolism, or excretion.

METHODS

We conducted a cross-sectional analysis of 598 premenopausal women who participated in a reproducibility study (n = 109) or served as controls in a nested case-control study of breast cancer (n = 489) within the Nurses' Health Study II. Dietary intakes of fiber and fat were assessed via semiquantitative food frequency questionnaires in 1995 and 1999. Midluteal urine samples were collected between 1996 and 1999 and EMs were quantified with the use of HPLC-tandem mass spectrometry. Linear mixed models were used to estimate creatinine-adjusted geometric means for individual EMs and their pathway groups across categories of dietary intake while controlling for total energy intake and potential confounders.

RESULTS

Higher total dietary fiber intake (>25 g/d vs. ≤15 g/d) was associated with significantly higher concentrations of 4-methoxyestradiol (50% difference, P-difference = 0.01, P-trend = 0.004) and lower concentrations of 17-epiestriol (-27% difference, P-difference = 0.03, P-trend = 0.03), but was not associated with any other EMs. The associations did not vary by fiber intake from different sources. Total fat intake (>35% energy vs. ≤25% energy) was suggestively positively associated with 17-epiestriol (22.6% difference, P-difference = 0.14, P-trend = 0.06); the association was significant for polyunsaturated fatty acid (37% difference, P-difference = 0.01, P-trend = 0.01) and trans fat (36.1% difference, P-difference = 0.01, P-trend = 0.01) intakes.

CONCLUSION

Fiber and fat intakes were not strongly associated with patterns of estrogen metabolism in premenopausal women. Our data suggest estrogen metabolism is not a major mechanism through which dietary fiber and fat may affect breast or other hormone-related cancer risks.

History of uterine leiomyomata and incidence of breast cancer

PURPOSE

Uterine leiomyomata (UL), benign tumors of the myometrium, are influenced by sex steroid hormones. A history of UL diagnosis has been associated with a higher risk of uterine malignancies. The relation between UL and breast cancer, another hormonally responsive cancer, has not been studied.

METHODS

We investigated the association between self-reported physician-diagnosed UL and incidence of breast cancer in the Black Women's Health Study, a prospective cohort study. We followed 57,747 participants without a history of breast cancer from 1995 to 2013. UL diagnoses were reported at baseline and biennially. Breast cancer was reported on biennial questionnaires and confirmed by pathology data from medical records or cancer registries. Cox regression was used to derive incidence rate ratios (IRRs) and 95 % confidence intervals (CI) and adjust for potential confounders.

RESULTS

There were 2,276 incident cases of breast cancer (1,699 invasive, 394 in situ, and 183 unknown) during 879,672 person-years of follow-up. The multivariable IRR for the overall association between history of UL and breast cancer incidence was 0.99 (95 % CI 0.90-1.08), with similar results for ER + (IRR = 1.03) and ER - breast cancer (IRR = 1.05). IRRs for early diagnosis of UL (before age 30) were slightly above 1.0, with IRRs of 1.14 (95 % CI 0.99-1.31) for overall breast cancer, 1.14 (95 % CI 0.93-1.40) for ER + breast cancer, and 1.20 (95 % CI 0.89-1.61) for ER - breast cancer. IRRs for early diagnosis of UL were elevated for breast cancer diagnosed before 40 years of age (IRR = 1.39, 95 % CI 0.97-1.99) and premenopausal breast cancer (IRR = 1.26, 95 % CI 1.01-1.58). No consistent patterns in risk were observed across estrogen receptor subtypes, and IRRs did not differ appreciably within strata of BMI, female hormone use, mammography recency, or family history of breast cancer.

CONCLUSIONS

The present study of US black women suggests that a history of UL diagnosis is unrelated to the incidence of breast cancer overall. The positive associations observed for early diagnosed UL with breast cancer before age 40 and with premenopausal breast cancer require confirmation in future studies.

Caffeine, coffee, and tea intake and urinary estrogens and estrogen metabolites in premenopausal women

BACKGROUND

Prior studies have found weak inverse associations between breast cancer and caffeine and coffee intake, possibly mediated through their effects on sex hormones.

METHODS

High-performance liquid chromatography/tandem mass spectrometry was used to quantify levels of 15 individual estrogens and estrogen metabolites (EM) among 587 premenopausal women in the Nurses' Health Study II with mid-luteal phase urine samples and caffeine, coffee, and/or tea intakes from self-reported food frequency questionnaires. Multivariate linear mixed models were used to estimate geometric means of individual EM, pathways, and ratios by intake categories, and P values for tests of linear trend.

RESULTS

Compared with women in the lowest quartile of caffeine consumption, those in the top quartile had higher urinary concentrations of 16α-hydroxyestrone (28% difference; Ptrend = 0.01) and 16-epiestriol (13% difference; Ptrend = 0.04), and a decreased parent estrogens/2-, 4-, 16-pathway ratio (Ptrend = 0.03). Coffee intake was associated with higher 2-catechols, including 2-hydroxyestradiol (57% difference, ≥4 cups/day vs. ≤6 cups/week; Ptrend = 0.001) and 2-hydroxyestrone (52% difference; Ptrend = 0.001), and several ratio measures. Decaffeinated coffee was not associated with 2-pathway metabolism, but women in the highest (vs. lowest) category of intake (≥2 cups/day vs. ≤1-3 cups/month) had significantly lower levels of two 16-pathway metabolites, estriol (25% difference; Ptrend = 0.01) and 17-epiestriol (48% difference; Ptrend = 0.0004). Tea intake was positively associated with 17-epiestriol (52% difference; Ptrend = 0.01).

CONCLUSION

Caffeine and coffee intake were both associated with profiles of estrogen metabolism in premenopausal women.

IMPACT

Consumption of caffeine and coffee may alter patterns of premenopausal estrogen metabolism.

HER2 status in molecular apocrine breast cancer: associations with clinical, pathological, and molecular features

Molecular apocrine breast cancer (MABC) is a distinct subtype of breast cancer. The purpose of this study was to investigate the relationship between HER2 status and clinicopathologic characteristics of MABCs from Chinese Han cohort. A cohort of 90 MABC patients were enrolled. Immunohistochemical method was performed to analyze the molecular expression, and the human epidermal growth factor receptor 2 (HER2) amplification was verified by fluorescence in situ hybridization (FISH). By studying these 90 MABC cases, the majority of studied patients were premenopausal young women (median age 48 yr) with high grade tumors. We also found that MABCs had high positive expression rates of HER2, CK8, CD44, CD166, p53 and BRCA1, the elevated Ki-67 labeling index, and favorable prognosis. There was a significantly higher incidence of lymph node metastasis and lower CD166 positive rate in HER2-negative patients compared to HER2-positive patients (54.5% vs. 37.0%, P = 0.044 and 72.7% vs. 91.3%, P = 0.021, respectively). The CK5/6 and EGFR expression rates were significant higher in HER2-negative cases than in HER2-positive cases, suggesting that there is overlap between MABC with HER2-negative phenotype and basal-like breast cancer. In addition, HER2 positive was found to be significantly associated a poor overall survival in MABCs. In conclusion, HER2 are highly expressed, and HER2 positivity could be considered as a significant biomarker of poor prognosis in MABC. The results also suggest that a subtype tumor with distinct patterns of molecule expression depending on HER2 status presented in MABC.

Endogenous estrogens and the risk of breast, endometrial, and ovarian cancers

Data from laboratory and epidemiologic studies support a relationship between endogenous hormones and the increased risk of several female cancers. In epidemiologic studies, consistent associations have been observed between risk of breast, ovarian and endometrial cancers and reproductive and hormonal risk factors such as high postmenopausal body mass index (BMI) and postmenopausal hormone use, which suggest the importance of endogenous hormones in the etiology of these diseases. The relationship between circulating estrogen levels in postmenopausal women and the risk of breast cancer is well established, with an approximately 2-fold higher risk among women in the top 20-25% (versus bottom 20-25%) of levels. However, data evaluating the relationship between endogenous estrogens and premenopausal breast cancer risk are more limited and less consistent. Two studies to date have evaluated the relationship between circulating estrogens and breast cancer risk by menstrual cycle phase at blood collection and only one study has examined this relationship by menopausal status at diagnosis. Three prospective studies have evaluated circulating estrogen levels and endometrial cancer risk in postmenopausal women, with consistent strong positive associations reported (with relative risks of 2-4 comparing high versus low hormone levels), while this relationship has not been studied in premenopausal women. Compared to breast and endometrial cancers, reproductive and hormonal characteristics such as postmenopausal hormone use are generally weaker and less consistent risk factors for ovarian cancer, and the only small prospective study conducted to date indicated a non-significant positive relationship between circulating estrogen levels and ovarian cancer risk. In this review, we summarize current evidence and identify key areas to be addressed in future epidemiologic studies of endogenous estrogens and the risk of breast, endometrial, and ovarian cancers.

Breast cancer incidence after hormonal treatments for infertility: systematic review and meta-analysis of population-based studies

The increasing practice of hormonal infertility treatments (HITs) raised concerns about their effects on breast cancer (BC) risk. Available evidence reported conflicting results. The aim of this study was to assess the potential association between HITs and BC risk. The literature was searched through November 2014. Eligible studies included cohort studies reporting BC incidence in women undergone HITs. Data were analyzed with standard meta-analytic techniques. Subgroup analyses were performed by type of intervention (IVF vs. NO IVF), follow-up duration (<10 vs. >10 years), and type of control (population vs. infertile). 20 eligible studies (207.914 women, 2347 BC) were retrieved: no increased risk was detected (SRR = 1.05, 95 % CI 0.96-1.14), with a significant heterogeneity (I (2) = 59 %, p = 0.001) among studies. In the seven studies with the in vitro fertilization (IVF) procedure, no increase in BC risk was observed (SRR = 0.96, 95 % CI 0.80-1.14); in the three NO IVF studies, an increased BC risk was identified (SRR = 1.26, 95 %CI 1.06-1.50). A borderline interaction between type of intervention (IVF vs. NO IVF) and BC risk was observed (p = 0.06). An increased risk with longer follow-up (≥10 vs. <10 years) was detected (SRR = 1.13, 95 % CI 1.02-1.26 vs. SRR = 0.95, 95 % CI 0.85-1.06). Overall, HITs are not associated with an increased BC risk. In particular, no increased risk was observed in women undergoing IVF. Conversely, an increased in BC risk cannot be ruled out with older treatment protocols based on clomiphene. The long-term administration of clomiphene outside the current indications should be discouraged because of a possible increase in BC risk.

Migraine and breast cancer risk: a prospective cohort study and meta-analysis

BACKGROUND

The evidence for an association between migraine and breast cancer risk is inconclusive. While female sex hormones have been proposed as one underlying mechanism, data on sex hormone levels in migraineurs are sparse.

METHODS

We prospectively evaluated the association between migraine and breast cancer risk among 115378 Nurses' Health Study II participants using Cox proportional hazards models. Differences in endogenous sex hormone levels according to migraine status were assessed among 2034 premenopausal women using linear regression. We performed a meta-analysis of studies investigating the association between migraine and invasive breast cancer risk published through October 2013. All statistical tests were two-sided.

RESULTS

Seventeen thousand six hundred ninety-six women (15.3%) reported a physician's diagnosis of migraine at baseline. Over 20 years of follow-up, 833 in situ and 3091 invasive breast malignancies occurred. Migraine was not associated with total (hazard ratio [HR] = 0.96, 95% confidence interval [CI] = 0.88 to 1.04), in situ (HR = 0.97, 95% CI = 0.82 to 1.15), or invasive breast cancer risk (HR = 0.95, 95% CI = 0.87 to 1.04). Endogenous sex hormone levels did not differ according to migraine status. In the meta-analysis, migraine was associated with a lower risk of breast cancer overall (pooled risk ratio [RR] = 0.84, 95% CI = 0.73 to 0.98). However, this inverse association was apparent only among case-control studies (pooled RR = 0.72, 95% CI = 0.66 to 0.79), and not among cohort studies (pooled RR = 0.98, 95% CI = 0.87 to 1.10).

CONCLUSION

In this large cohort study, migraine was not associated with breast cancer risk or differences in endogenous sex hormone levels. While case-control studies suggest an inverse association between migraine and breast cancer risk, prospective cohort studies do not support an association in pooled analyses.

Alcohol consumption in relation to plasma sex hormones, prolactin, and sex hormone-binding globulin in premenopausal women

BACKGROUND

Alcohol consumption is a consistent risk factor for breast cancer, and evidence suggests premenopausal plasma hormones are associated with breast cancer.

METHODS

Plasma concentrations of estradiol, estrone, estrone sulfate, testosterone, androstenedione, progesterone, prolactin, dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS), and sex hormone-binding globulin (SHBG) were measured in samples collected in 1996-99. Average alcohol intake was calculated from semiquantitative food frequency questionnaires collected in 1995 and 1999. We used generalized linear models to calculate geometric mean hormone concentrations across alcohol categories and the percentage difference for the highest versus lowest category.

RESULTS

Comparing women who consumed >20 g/d with nondrinkers, levels were 25.7% higher for luteal estrone (geometric mean, 106 vs. 84.5 pg/mL; Ptrend = 0.001), 27.2% higher for luteal estradiol (182 vs. 143 pg/mL; Ptrend = 0.006), and 16.8% higher for SHBG (85.6 vs. 73.3 nmol/L; Ptrend = 0.03); concentrations of free testosterone were 17.9% lower (0.16 vs. 0.20 ng/dL; Ptrend = 0.002). Women consuming >10 g/d compared with nondrinkers had 26.5% higher concentrations of follicular estrone sulfate (950 vs. 751 pg/mL; Ptrend = 0.04). We did not observe significant associations between alcohol and the other sex hormones evaluated. Significant positive associations were observed with beer intake, but not other alcohol types, for DHEA (Pinteraction = 0.003) and androstenedione (Pinteraction = 0.006).

CONCLUSION

Alcohol consumption was significantly positively associated with plasma luteal estrogen concentrations, but not with androgen levels, nor estrone or estradiol measured in the follicular phase.

IMPACT

Differences in premenopausal estrogen levels may contribute to the association between alcohol and breast cancer.

Diverse pathomechanisms leading to the breakdown of cellular estrogen surveillance and breast cancer development: new therapeutic strategies

Recognition of the two main pathologic mechanisms equally leading to breast cancer development may provide explanations for the apparently controversial results obtained by sexual hormone measurements in breast cancer cases. Either insulin resistance or estrogen receptor (ER) defect is the initiator of pathologic processes and both of them may lead to breast cancer development. Primary insulin resistance induces hyperandrogenism and estrogen deficiency, but during these ongoing pathologic processes, ER defect also develops. Conversely, when estrogen resistance is the onset of hormonal and metabolic disturbances, initial counteraction is hyperestrogenism. Compensatory mechanisms improve the damaged reactivity of ERs; however, their failure leads to secondary insulin resistance. The final stage of both pathologic pathways is the breakdown of estrogen surveillance, leading to breast cancer development. Among premenopausal breast cancer cases, insulin resistance is the preponderant initiator of alterations with hyperandrogenism, which is reflected by the majority of studies suggesting a causal role of hyperandrogenism in breast cancer development. In the majority of postmenopausal cases, tumor development may also be initiated by insulin resistance, while hyperandrogenism is typically coupled with elevated estrogen levels within the low postmenopausal hormone range. This mild hyperestrogenism is the remnant of reactive estrogen synthesis against refractory ERs that were successfully counteracted at a younger age. When refractoriness of ERs is the initiator of pathologic processes, reactively increased estrogen levels may be found in both young and older breast cancer cases, while they may exhibit clinical symptoms of estrogen deficiency. Studies justifying a causal correlation between hyperestrogenism and tumor development compile such breast cancer cases. In conclusion, the quantitative evaluation of ER refractoriness in breast cancer cases has great importance, since the stronger the estrogen resistance, the higher the promising dose of estrogen therapy.

Metabolomic patterns and alcohol consumption in African Americans in the Atherosclerosis Risk in Communities Study

BACKGROUND

Effects of alcohol consumption on health and disease are complex and involve a number of cellular and metabolic processes.

OBJECTIVE

We examined the association between alcohol consumption habits and metabolomic profiles.

DESIGN

We conducted a cross-sectional study to explore the association of alcohol consumption habits measured by using a questionnaire with serum metabolites measured by using untargeted mass spectrometry in 1977 African Americans from the Jackson field center in the Atherosclerosis Risk in Communities Study. The whole sample was split into a discovery set (n = 1500) and a replication set (n = 477). Alcohol consumption habits were treated as an ordinal variable, with nondrinkers as the reference group and quartiles of current drinkers as ordinal groups with higher values. For each metabolite, a linear regression was conducted to estimate its relation with alcohol consumption habits separately in both sets. A modified Bonferroni procedure was used in the discovery set to adjust the significance threshold (P < 1.9 × 10⁻⁴).

RESULTS

In 356 named metabolites, 39 metabolites were significantly associated with alcohol consumption habits in both discovery and replication sets. In general, alcohol consumption was associated with higher levels of most metabolites such as those in amino acid and lipid pathways and with lower levels of γ-glutamyl dipeptides. Three pathways, 2-hydroxybutyrate-related metabolites, γ-glutamyl dipeptides, and lysophosphatidylcholines, which are considered to be involved in inflammation and oxidation, were associated with incident cardiovascular diseases.

CONCLUSIONS

To our knowledge, this is the largest metabolomic study thus far conducted in nonwhites. Metabolomic biomarkers of alcohol consumption were identified and replicated. The results lend new insight into potential mediating effects between alcohol consumption and future health and disease.

Genetic variation at CYP3A is associated with age at menarche and breast cancer risk: a case-control study

INTRODUCTION

We have previously shown that a tag single nucleotide polymorphism (rs10235235), which maps to the CYP3A locus (7q22.1), was associated with a reduction in premenopausal urinary estrone glucuronide levels and a modest reduction in risk of breast cancer in women age ≤50 years.

METHODS

We further investigated the association of rs10235235 with breast cancer risk in a large case control study of 47,346 cases and 47,570 controls from 52 studies participating in the Breast Cancer Association Consortium. Genotyping of rs10235235 was conducted using a custom Illumina Infinium array. Stratified analyses were conducted to determine whether this association was modified by age at diagnosis, ethnicity, age at menarche or tumor characteristics.

RESULTS

We confirmed the association of rs10235235 with breast cancer risk for women of European ancestry but found no evidence that this association differed with age at diagnosis. Heterozygote and homozygote odds ratios (ORs) were OR = 0.98 (95% CI 0.94, 1.01; P = 0.2) and OR = 0.80 (95% CI 0.69, 0.93; P = 0.004), respectively (P(trend) = 0.02). There was no evidence of effect modification by tumor characteristics. rs10235235 was, however, associated with age at menarche in controls (P(trend) = 0.005) but not cases (P(trend) = 0.97). Consequently the association between rs10235235 and breast cancer risk differed according to age at menarche (P(het) = 0.02); the rare allele of rs10235235 was associated with a reduction in breast cancer risk for women who had their menarche age ≥15 years (OR(het) = 0.84, 95% CI 0.75, 0.94; OR(hom) = 0.81, 95% CI 0.51, 1.30; P(trend) = 0.002) but not for those who had their menarche age ≤11 years (OR(het) = 1.06, 95% CI 0.95, 1.19, OR(hom) = 1.07, 95% CI 0.67, 1.72; P(trend) = 0.29).

CONCLUSIONS

To our knowledge rs10235235 is the first single nucleotide polymorphism to be associated with both breast cancer risk and age at menarche consistent with the well-documented association between later age at menarche and a reduction in breast cancer risk. These associations are likely mediated via an effect on circulating hormone levels.