Association of estrogen receptor alpha polymorphisms with breast cancer risk in older Caucasian women

A comprehensive meta-analysis to identify susceptibility genetic variants for precocious puberty

PURPOSE

Currently, several genetic variants in ERα gene (rs2234693 and rs9340799), ERβ gene (rs1256049 and rs4986938), KISS1 gene (rs4889, rs1132506 and rs5780218), LIN28B gene (rs314263, rs314276 and rs314280), and MKRN3 gene (rs2239669) have been repeatedly explored for their contribution to precocious puberty (PP) susceptibility. However, the results remain conflicting rather than conclusive. We here performed a meta-analysis to identify the real susceptibility genetic variants for PP.

METHODS

After screening by inclusion criteria, 20 related studies were finally included in this meta-analysis. The odds ratios and 95% confidence intervals were calculated to assess the strength of association. Sensitive analysis, publication bias, and trial sequential analysis (TSA) were performed to evaluate the stability and reliability of results.

RESULTS

Rs2234693, rs9340799, and rs1256049 were significantly associated with PP susceptibility (p < 0.0084). Stratified analysis according to ethnicity showed that rs2234693 and rs9340799 were significantly associated with PP susceptibility in Asian and Chinese populations. Stratified analysis according to PP subtype showed that rs2234693 and rs9340799 were significantly associated with idiopathic central PP susceptibility in Asian and Chinese populations (p < 0.0084). The results of publication bias, sensitivity analysis, and TSA provided solid evidence for the association between these three variants and PP susceptibility.

CONCLUSIONS

Rs2234693 and rs9340799 in ERα gene and rs1256049 in ERβ gene may serve as susceptive factors for PP development. The present finding should be confirmed in replication studies and reinforced in functional studies, which will ultimately improve the feasibility of the application of these three PP-susceptible loci in clinical practice.

The rs9340799 polymorphism of the estrogen receptor alpha (ESR1) gene and its association with breast cancer susceptibility

The ESR1 rs9340799 polymorphism has been frequently investigated with regard to its association with breast cancer (BC) susceptibility, but the findings have been inconclusive. In this work, we aimed to address the inconsistencies in study findings by performing a systematic review and meta-analysis. Eligible studies were identified from the Web of Science, PubMed, Scopus, China National Knowledge Infrastructure, VIP and Wanfang databases based on the predefined inclusion and exclusion criteria. The pooled odds ratio (OR) was then calculated under five genetic models: homozygous (GG vs. AA), heterozygous (AG vs. AA), dominant (AG + GG vs. AA), recessive (GG vs. AA + AG) and allele (G vs. A). Combined results from 23 studies involving 34,721 subjects indicated a lack of significant association between the polymorphism and BC susceptibility (homozygous model, OR = 1.045, 95% CI 0.887-1.231, P = 0.601; heterozygous model, OR = 0.941, 95% CI 0.861-1.030, P = 0.186; dominant model, OR = 0.957, 95% CI 0.875-1.045, P = 0.327; recessive model, OR = 1.053, 95% CI 0.908-1.222, P = 0.495; allele model, OR = 0.987, 95% CI 0.919-1.059, P = 0.709). Subgroup analyses by ethnicity, menopausal status and study quality also revealed no statistically significant association (P > 0.05). In conclusion, our results showed that the ESR1 rs9340799 polymorphism was not associated with BC susceptibility, suggesting its limited potential as a genetic marker for BC.

The variant T allele of PvuII in ESR1 gene is a prognostic marker in early breast cancer survival

The PvuII (rs2234693) Single Nucleotide Polymorphism (SNP) in the gene coding for the estrogen receptor-1 (ESR1), has been found associated with outcome in tamoxifen treated patients with early hormone-receptor positive breast cancer. However, it remains unclear whether this SNP is a predictive marker for tamoxifen efficacy or a prognostic marker for breast cancer outcome. The aim of this study was to examine the prognostic potential of this SNP in postmenopausal early breast cancer patients treated with adjuvant exemestane. Dutch postmenopausal patients randomised to 5 years of adjuvant exemestane of whom tissue was available (N = 807) were selected from the Tamoxifen Exemestane Adjuvant Multinational (TEAM) trial database. The SNP rs2234693 in the ESR1 gene was genotyped on DNA from formalin-fixed paraffin embedded (FFPE) tumor tissue using Taqman assays and related to the primary endpoint disease-free survival (DFS) and secondary endpoint overall survival (OS). Survival analyses were performed using Cox regression analysis. In total 805 patients were included in the analyses (median follow up of 5.22 years) and genotypes were obtained in 97% of the samples. The variant T allele of PvuII in ESR1 (rs2234693) was associated with a better DFS (hazard ratio (HR) 0.689, 95% confidence interval (CI) 0.480–0.989, P = 0.044) in univariate analysis only, and a better OS in both univariate (HR 0.616, 95%, CI 0.411–0.923, P = 0.019) and multivariate analyses (HR 0.571, 95% CI 0.380–0.856, P = 0.007), consistent with a prognostic rather than a predictive drug response effect. Variation of PvuII in the ESR1 gene is related to OS in postmenopausal, early HR + breast cancer patients treated with exemestane in the TEAM study. Variation in the ESR1 gene may therefore be a prognostic marker of early breast cancer survival, and warrants further research.

Phytoestrogen exposure alters endometrial stromal cells and interferes with decidualization signaling

OBJECTIVE

To investigate whether phytoestrogens (genistein and daidzein) alter in vitro decidualization of human endometrial stromal cells (ESCs).

DESIGN

Isolated primary ESCs were exposed to phytoestrogens and decidualized in vitro.

SETTING

Academic fertility center.

PATIENT(S)

Twenty fertile oocyte donors attending the IVI Valencia clinic.

INTERVENTION(S)

Treatment of ESC with phytoestrogens at 0, 10, 20, 50, and 100 μM.

MAIN OUTCOME MEASURE(S)

The ESC proliferation was analyzed by MTS assay. In vitro decidualization was induced in the presence of phytoestrogens by medroxyprogesterone acetate/cyclic adenosine 3':5' monophosphate and evaluated by prolactin (PRL) ELISA and F-actin immunostaining. The Ki67 proliferative marker was analyzed by immunofluorescence. The ESC apoptosis was assessed by annexin V/propidium iodide detection using flow cytometry. Estrogen (ERβ) and P receptor (PR) localization were evaluated by immunofluorescence.

RESULT(S)

The ESC exposed to 0, 19, 20, 50, and 100 μM of genistein, daidzein, and genistein + daidzein showed a dose-dependent proliferation decrease. After 48-96 hours of culture, this reduction was significant in the presence of 50 μM of phytoestrogens versus 10 μM untreated ESC. The ESC decidualized in the presence of phytoestrogens did not rearrange their cytoskeletons and showed a significant decrease in PRL secretion compared with untreated decidualized ESCs (dESCs). However, phytoestrogens did not alter proliferative status or the percentage of viable/apoptotic cells in dESC compared with untreated dESC. During decidualization, phytoestrogens induced the same nuclear translocation of ERβ and PR as the control dESC.

CONCLUSION(S)

This study reveals that high doses of phytoestrogens could affect the in vitro decidualization process.

ESR1 PvuII (rs2234693 T>C) polymorphism and cancer susceptibility: Evidence from 80 studies

Emerging epidemiological researches have been performed to assess the association of ESR1 PvuII (rs2234693 T>C) polymorphism with the risk of cancer, yet with conflicting conclusions. Therefore, this updated meta-analysis was performed to make a more accurate evaluation of such relationship. We adopted EMBASE, PubMed, CNKI, and WANFANG database to search relevant literature before January 2018. Odds ratios (ORs) and 95% confidence intervals (CIs) were employed to estimate the relationship strengths. In final, 80 studies (69 publications) involving 26428 cases and 43381 controls were enrolled. Our results failed to provide significant association between overall cancer risk and PvuII polymorphism under homozygous (TT vs. CC) and heterozygous (TT vs. CT) models. Statistically significant relationship was only observed for PvuII polymorphism in allele model T vs. C (OR=0.95, 95% CI=0.91-0.99). Stratification analysis by cancer type suggested that T genotype significantly decreased prostate cancer risk (TT vs. CC: OR=0.79, 95% CI=0.66-0.94; T vs. C: OR=0.89, 95% CI=0.82-0.98), Leiomyoma risk (T vs. C: OR=0.82, 95% CI=0.68-0.98), and HCC risk (TT vs. CC: OR=0.45, 95% CI=0.28-0.71; T vs. C: OR=0.67, 95% CI=0.47-0.95). Furthermore, significantly decreased risk was also found for Africans, population-based and hospital-based studies in the stratified analyses. These results suggest that ESR1 PvuII (rs2234693 T>C) polymorphism may only have little impact on cancer susceptibility. In the future, large-scale epidemical studies are warranted to verify these results.

Association between ERα gene Pvu II polymorphism and breast cancer susceptibility: A meta-analysis

BACKGROUND

Estrogen has played an important role in the development of breast cancer. ER-α PvuII gene polymorphism is in close association with the occurrence risk of breast cancer, but no consensus has been achieved currently.

METHODS

PubMed, Embase, China National Knowledge Infrastructure (CNKI) database, Wanfang database, and VIP database were retrieved to collect the case-control studies on association between ERα gene Pvu II polymorphism and breast cancer risk published before September 1, 2017. Newcastle-Ottawa Scale (NOS) was used to assess the quality of the literatures, Stata 14.0 software was applied for meta-analysis, and the pooled odds ratio (OR) and 95% confidence interval (95% CI) were calculated. The subgroup analysis was performed to assess the confounding factors, followed by assessment of publication bias and sensitivity analysis.

RESULTS

A total of 26 studies were enrolled in the analysis based on inclusion criteria, which included 15,360 patients and 26,423 controls. The results demonstrated that ERα gene Pvu II polymorphism was in significant association with the decrease of breast cancer risk in 3 genetic models (C vs T, OR = 0.962, 95% CI = 0.933-0.992, P = .012; CC vs TT, OR = 0.911, 95% CI = 0.856-0.969, P = .003; CC vs TT/CT, OR = 0.923, 95% CI = 0.874-0.975, P = .004). Subgroup analysis was conducted on the basis of ethnicity and source of controls, whose results illustrated that ERα gene Pvu II polymorphism was in significant association with the decrease of breast cancer risk in Asians rather than in Caucasians (CC vs TT, OR = 0.862, 95% CI = 0.750-0.922, P = .038; CC vs TT/CT, OR = 0.851, 95% CI = 0.755-0.959, P = .008). In population-based subgroup rather than in hospital-based subgroup, ERα gene Pvu II polymorphism was in significant association with the decrease of breast cancer risk in the allele model, homozygous model, dominant model, and recessive model (C vs T, OR = 0.943, 95% CI = 0.911-0.977, P = .001; CC vs TT, OR = 0.878, 95% CI = 0.817-0.944, P = .000; CC/CT vs TT, OR = 0.936, 95% CI = 0.881-0.994, P = .031; CC vs TT/CT, OR = 0.902, 95% CI = 0.847-0.960, P = .001).

CONCLUSION

ERα gene Pvu II polymorphism exerts an important function in the progression of breast cancer.

Association Between ESR1 PvuII, XbaI, and P325P Polymorphisms and Breast Cancer Susceptibility: A Meta-Analysis

Background

Breast cancer is one of the leading causes of cancer-related deaths for women. Numerous studies have shown that single-nucleotide polymorphisms (SNPs) on the ESR1 gene are associated to this disease. However, data and conclusions are inconsistent and controversial.

Material/Methods

To investigate the association between PvuII (rs2234693), XbaI (rs9340799) and P325P (rs1801132) polymorphisms of ESR1 gene with the risk of breast cancer under different population categorizations, we searched multiple databases for data collection, and performed the meta-analysis on a total of 25 case-control studies. Three different comparison models – dominant model, recessive model, and homozygote comparison model – were applied to evaluate the association.

Results

Our results indicated that people with TT+TC or TT genotype were at a greater risk of developing breast cancer than those with CC genotype in the PvuII polymorphism. While for XbaI and P325P polymorphisms, no significance was found using any of the 3 models. Furthermore, the data were also stratified into different subgroups according to the ethnicity (white or Asian) and source of controls (hospital-based or population-based), and separate analyses were conducted to assess the association. The ethnicity subgroup assessment showed that the higher risk of breast cancer for TT genotype of PvuII polymorphism than CC genotype only occurred in Asian people, but not in white populations. For the source-stratified subgroup analysis, significant association suggested that people with TT + TC genotype were at a greater risk of developing breast cancer than those with CC genotype in the hospital-based subgroup.

Conclusions

Thus, this meta-analysis clarified the inconsistent conclusions from previous studies, conducted analyses for the entire population as well as for different subgroups using diverse population categorization strategies, and has the potential to help provide a personalized risk estimate for breast cancer susceptibility.

The relationship between estrogen receptor gene polymorphism and mammographic density in postmenopausal women

OBJECTIVE

To assess the relationship between the presence of PVUII and XBAI polymorphisms in the estrogen receptor α gene and mammographic density in postmenopausal women.

METHODS

For the present analysis, 189 postmenopausal women who had never used hormonal therapy and who did not have clinical or mammographic features were selected. Based on the ACR-BIRADS(®) 2003 classification, the mammographic density was determined by three independent readers (two subjective ratings and one computerized). Blood samples were available to extract DNA according to KIT GFX(®) protocol. PCR-RFLP was then used to identify the polymorphisms.

RESULTS

There was a high degree of agreement among the three readers to determine the mammographic density (κ > 0.75). Sixty women (32%) had dense breasts and 129 (68%) had non-dense breasts. The PVUII polymorphism was found in 132 (69.8%) of 189 women, while the XBAI polymorphism was found in 135 (71.4%) women. Parity (p = 0.02) and body mass index (p < 0.0001) were associated with mammographic density. It was observed that, for the XBAI polymorphism, women with two mutated alleles were approximately 2.5 times more likely to be classified in the dense breasts group (p = 0.003) and the presence of both wild alleles was associated with fibroglandular tissue replacement by fat (p = 0.02).

CONCLUSIONS

There was no significant association of the PVUII polymorphism in the estrogen receptor α gene with mammographic density (p = 0.34). However, the XBAI polymorphism was observed at a higher mutated homozygous frequency in women with dense breasts and there was an increased frequency of wild-type homozygous and heterozygous women with fat-replaced breasts (p = 0.01).

Reported early family environment covaries with menarcheal age as a function of polymorphic variation in estrogen receptor-α

Age at menarche, a sentinel index of pubertal maturation, was examined in relation to early family relationships (conflict, cohesion) and polymorphic variation in the gene encoding estrogen receptor-α (ESR1) in a midlife sample of 455 European American women. Consistent with prior literature, women who reported being raised in families characterized by close interpersonal relationships and little conflict tended to reach menarche at a later age than participants reared in families lacking cohesion and prone to discord. Moreover, this association was moderated by ESR1 variation, such that quality of the family environment covaried positively with menarcheal age among participants homozygous for minor alleles of the two ESR1 polymorphisms studied here (rs9304799, rs2234693), but not among women of other ESR1 genotypes. In addition, (a) family relationship variables were unrelated to ESR1 variation, and (b) genotype-dependent effects of childhood environment on age at menarche could not be accounted for by personality traits elsewhere shown to explain heritable variation in reported family conflict and cohesion. These findings are consistent with theories of differential susceptibility to environmental influence, as well as the more specific hypothesis (by Belsky) that girls differ genetically in their sensitivity to rearing effects on pubertal maturation.

Oestrogen receptor-alpha polymorphism and risk of fracture: a meta-analysis of 13 studies including 1279 cases and 6069 controls

A meta-analysis was performed to evaluate the effect of oestrogen receptor-alpha (ESR1) gene PvuII polymorphism on fracture risk. It included published data from relevant studies (up to May 2010) identified from Medline, Embase and Current Contents. The 13 included studies contained 1279 fracture cases and 6069 controls. The combined results based on these studies showed no relationship between ESR1 gene PvuII polymorphism and fracture risk. No significant difference in genotype distribution was found when stratifying by race. When stratifying by fracture type, it was found that vertebral fracture cases had a significantly higher frequency of the PvuII pp genotype than controls in five studies (552 cases and 2350 controls). This meta-analysis suggests a modest but statistically significant association between the ESR1 PvuII pp genotype and vertebral fracture.

Genetic determinants of extracellular magnesium concentration: analysis of multiple candidate genes, and evidence for association with the estrogen receptor alpha (ESR1) locus

BACKGROUND

Serum magnesium concentration is a quantitative trait with substantial heritability. Although the pool of candidate genes continues to grow, only the histocompatibility locus has been associated with magnesium levels. To explore other possibilities, we targeted 6 candidate genes physiologically relevant to magnesium metabolism.

METHODS

We studied a large cohort (n=471) derived from a well-characterized population of healthy Caucasian women 18 to 35 years. Total serum magnesium and calcium were measured by atomic absorption spectrophotometry (aaMg & aaCa). Genomic DNA was amplified and SNPs in candidate genes (CASR, VDR, ESR1, CLDN16, EGF1, TRPM6) genotyped by routine methods.

RESULTS

We found a significant association between estrogen receptor alpha (ESR1) polymorphisms, PvuII and XbaI, and magnesium (r=-0.116, p=0.012 and r=-0.126, p=0.006, respectively). Stratifying by PvuII genotype (P/p alleles), the mean adjusted total magnesium (aaMg) concentration was significantly higher (p=0.01) in the pp group (0.823+/-0.005 mmol/l, n=130) than in PP homozygotes (0.805+/-0.006 mmol/l, n=70), and the mean in Pp heterozygotes was intermediate (0.810+/-0.005 mmol/l, n=180). No significant associations were observed with the other candidate genes tested.

CONCLUSIONS

The significant association between magnesium and ESR1 polymorphisms supports previous studies linking physiologic changes in serum magnesium to estrogen status.

ESR1 and EGF genetic variation in relation to breast cancer risk and survival

Introduction

Oestrogen exposure is a central factor in the development of breast cancer. Oestrogen receptor alpha (ESR1) is the main mediator of oestrogen effect in breast epithelia and has also been shown to be activated by epidermal growth factor (EGF). We sought to determine if common genetic variation in the ESR1 and EGF genes affects breast cancer risk, tumour characteristics or breast cancer survival.

Methods

We genotyped 157 single nucleotide polymorphisms (SNPs) in ESR1 and 54 SNPs in EGF in 92 Swedish controls and selected haplotype tagging SNPs (tagSNPs) that could predict both single SNP and haplotype variation in the genes with an R² of at least 0.8. The tagSNPs were genotyped in 1,590 breast cancer cases and 1,518 controls, and their association with breast cancer risk, tumour characteristics and survival were assessed using unconditional logistic regression models, Cox proportional hazard models and haplotype analysis.

Results

The single tagSNP analysis did not reveal association evidence for breast cancer risk, tumour characteristics, or survival. A multi-locus analysis of five adjacent tagSNPs suggested a region in ESR1 (between rs3003925 and rs2144025) for association with breast cancer risk (p = 0.001), but the result did not withstand adjustment for multiple comparisons (p = 0.086). A similar region was also implicated by haplotype analyses, but its significance needs to be verified by follow-up analysis.

Conclusion

Our results do not support a strong association between common variants in the ESR1 and EGF genes and breast cancer risk, tumour characteristics or survival.

Estrogen receptor genotype and risk of cognitive impairment in elders: findings from the Health ABC study

OBJECTIVE

To determine whether variants in the estrogen receptors 1 (alpha) and 2 (beta) (ESR1 and ESR2) genes are associated with cognitive impairment in non-demented elderly men and women.

BACKGROUND

Several single nucleotide polymorphisms (SNPs) on ESR1 and ESR2 genes have been associated with a range of hormone sensitive diseases such as breast cancer and osteoporosis. Genetic variations in ESR may also influence cognitive aging but are less studied, especially among men.

METHODS

We studied 2527 participants enrolled in an ongoing prospective study of community-dwelling elders. Four SNPs from ESR1 and four from ESR2 were analyzed. We measured cognitive function with the Modified Mini-Mental Status Examination (3MS) at baseline and biannually; cognitive impairment was defined as a decline of five or more points over 4 years. We calculated odds of developing cognitive impairment across SNPs using gender-stratified logistic regression and adjusted analyses for age, education, baseline 3MS score and in addition for race.

RESULTS

One thousand three hundred and forty-three women (mean age 73.4) and 1184 men (mean age 73.7) comprised our cohort. Among women, after multivariate adjustment, two of the ESR1 SNPs (rs8179176, rs9340799) and two of the ESR2 SNPs (rs1256065, rs1256030) were associated with likelihood of developing cognitive impairment, although the association for rs8179176 was of trend level significance. In men, one of the ESR1 SNPs (rs728524) and two of the ESR2 (rs1255998, rs1256030) were associated with cognitive impairment. Further adjustment for race attenuated the results somewhat. There was no association between any ESR SNP and level of bioavailable estradiol but testosterone level did vary among two of the SNPs (p<0.05).

CONCLUSION

We found that among non-demented community elders, several SNPs in the ESR1 and ESR2 genes were associated with risk of developing cognitive impairment. These findings suggest that estrogen receptor genetic variants may play a role in cognitive aging.

Active and passive smoking, IL6, ESR1, and breast cancer risk

We evaluated the association between smoking and risk of breast cancer in non-Hispanic white (NHW) and Hispanic or American Indian (HAI) women living in the Southwestern United States. Data on lifetime exposure to active and passive smoke data were available from 1527 NHW cases and 1601 NHW controls; 798 HAI cases and 924 HAI controls. Interleukin 6 (IL6) and Estrogen Receptor alpha (ESR1) polymorphisms were assessed in conjunction with smoking. Pack-years of smoking (>or=15) were associated with increased risk of pre-menopausal breast cancer among NHW women (OR 1.6, 95% CI 1.1-2. 4). Passive smoke increased risk of pre-menopausal breast cancer for HAI women (OR 1.9, 95% CI 1.1-3.1 everyone; OR 2.3, 95% CI 1.2-4.5 nonsmokers). HAI pre-menopausal women who were exposed to 10+ h of passive smoke per week and had the rs2069832 IL6 GG genotype had over a fourfold increased risk of breast cancer (OR 4.4, 95% CI 1.5-12.8; P for interaction 0.01). Those with the ESR1 Xba1 AA genotype had a threefold increased risk of breast cancer if they smoked>or=15 pack-years relative to non-smokers (P interaction 0.01). These data suggest that breast cancer risk is associated with active and passive smoking.

Estrogen receptor alpha polymorphisms and postmenopausal breast cancer risk

Background

The estrogen receptor alpha (ESR1) is a mediator of estrogen response in the breast. The most studied variants in this gene are the PvuII and XbaI polymorphisms, which have been associated to lower sensitivity to estrogen. We evaluated whether these polymorphisms were associated with breast cancer risk by means of an association study in a population of Caucasian postmenopausal women from the Rotterdam study and a meta-analysis of published data.

Methods

The PvuII and XbaI polymorphisms were genotyped in 3,893 women participants of the Rotterdam Study. Baseline information was obtained through a questionnaire. We conducted logistic regression analyses to assess the risk of breast cancer by each of the ESR1 genotypes. Meta-analyses of all publications on these relations were done by retrieving literature from Pubmed and by further checking the reference lists of the articles obtained.

Results

There were 38 women with previously diagnosed breast cancer. During follow-up, 152 were additionally diagnosed. The logistic regression analyses showed no difference in risk for postmenopausal breast cancer in carriers of the PvuII or XbaI genotypes neither in overall, incident or prevalent cases. No further evidence of a role of these variants was found in the meta-analysis.

Conclusions

Our results suggest that the ESR1 polymorphisms do not play a role in breast cancer risk in Caucasian postmenopausal women.

Estrogen Receptor α Polymorphism and Risk of Cardiovascular Disease, Cancer, and Hip Fracture

BACKGROUND

We hypothesized that the estrogen receptor alpha (ESR1) IVS1-397T/C polymorphism affects high-density lipoprotein cholesterol response to hormone replacement therapy and risk of cardiovascular disease (CVD), cancer of reproductive organs, and hip fracture.

METHODS AND RESULTS

We studied cross-sectionally 9244 individuals from the Danish general population and followed them up for 23 to 25 years. End points were CVD (ischemic heart disease, myocardial infarction, angina pectoris, ischemic cerebrovascular disease, ischemic stroke, other ischemic cerebrovascular disease, venous thromboembolism, deep vein thrombosis, and pulmonary embolism), cancer of reproductive organs (breasts, ovaries, uterus, and prostate), and hip fracture. We also studied patients with ischemic heart disease (n=2495), ischemic cerebrovascular disease (n=856), and breast cancer (n=1256) versus general population controls. The CC, CT, and TT genotypes had general population frequencies of 21%, 50%, and 29%, respectively. Cross-sectionally, genotype did not influence high-density lipoprotein cholesterol response to hormone replacement therapy. In the cohort study, there were no differences in risks of CVD, cancer of reproductive organs, or hip fracture between genotypes. In case-control studies, risk of CVD did not differ between genotypes; however, the odds ratio for breast cancer in women with TT versus CC genotypes was 1.4 (95% CI, 1.1 to 1.7). Meta-analysis in men of 6 previous and the present 2 studies, including 4799 cases and 12,190 controls, showed odds ratios in CC versus CT and TT genotypes for fatal and nonfatal myocardial infarction of 0.81 (95% CI, 0.59 to 1.12) and 1.08 (95% CI, 0.97 to 1.21).

CONCLUSIONS

ESR1 IVS1-397T/C polymorphism does not influence high-density lipoprotein cholesterol response to hormone replacement therapy or risk of CVD, most cancers of reproductive organs, or hip fracture.

Estrogen receptor alpha haplotypes and breast cancer risk in older Caucasian women

Life-long exposure to estrogen is an established risk factor for breast cancer development. The underlying mechanism has been suggested to be the binding of estrogen-to-estrogen receptors in mammary tissue, which in turn promotes the proliferation and differentiation of breast tissue. Polymorphisms and haplotypes in estrogen receptor alpha (ESR1) have been reportedly associated with breast cancer risk; however, the results are not fully consistent. In this study, we investigated breast cancer risk associated with genotypes and haplotypes resulting from four ESR1 single nucleotide polymorphisms (SNPs), rs746432, rs2234693, rs9340799, and rs1801132. Genotyping has been performed on 393 breast cancer cases and 790 randomly selected controls in 1,183 Caucasian women over age 65 from the Study of Osteoporotic Fractures (SOF). We observed an allelic protective effect for SNP rs9340799 with an estimated odds ratio (OR) of 0.82 (95% CI = 0.68-1.00; P = 0.04) after adjustment for age, BMI and hip BMD. A protective effect of this SNP has been reported before in several different studies. We did not replicate the previously reported C-C-A-G haplotype association to breast cancer-the C-C-A-G haplotype from these SNPs was rare in this study (estimated frequency below 0.001% in cases and controls). No other statistically significant associations were observed between ESR1 haplotypes from the same four SNPs and the risk of breast cancer in older Caucasian women.

ESR1, AR, body size, and breast cancer risk in Hispanic and non-Hispanic white women living in the Southwestern United States

Estrogen and androgen are thought to influence breast cancer risk. The actions of estrogens and androgens are mediated through the respective receptors. In this study we examine the association of the Xb1 polymorphism of estrogen receptor alpha (ESR1) and the CAG repeat of the androgen receptor (AR) gene with risk of breast cancer in women living in the Southwestern United States. Cases (N = 1169 non-Hispanic white (NHW) and 576 Hispanic) with first primary breast cancer were matched to controls (N = 1330 NHW and 725 Hispanic) by location (Arizona, Colorado, New Mexico, or Utah) and 5-year age group. Detailed weight history was obtained along with other diet and lifestyle information. Neither the ESR1 nor the AR polymorphisms evaluated were associated independently with breast cancer risk in either Hispanic or NHW women. However, among Hispanic women taking hormone replacement therapy (HRT), there was a 40% reduced risk of breast cancer among women with an X allele (95% CI 0.39, 0.94). Also Hispanic women with the xx genotype had a significant reduced risk of breast cancer in the presence of weight gain prior to age 50 if post-menopausal or prior to diagnosis if pre-menopausal (P interaction 0.02 and <0.01 respectively). These results suggest differences in risk factors for NHW and Hispanic women. However, they provide only minor support for the role of the AR and ESR1 gene in the etiology of breast cancer.

Vasomotor symptom prevalence is associated with polymorphisms in sex steroid-metabolizing enzymes and receptors

The relation of single nucleotide polymorphisms (SNPs) of genes involved in estrogen function to vasomotor symptoms (VMS) has been inadequately explored. We evaluated SNPs in sex steroid-metabolizing genes and estrogen receptors (ERs) for their association with VMS (hot flashes, night sweats, and/or cold sweats) reported by women who were premenopausal or in early perimenopause at baseline. The study population was drawn from participants in the Study of Women's Health Across the Nation (SWAN). African American, Caucasian, Chinese, and Japanese women, 42 to 52 years of age at baseline, who were enrolled in the longitudinal, community-based cohort of SWAN provided questionnaire, interview, weight and height measurements, and serum samples through the sixth annual visit. SNPs associated with the sex steroid hormone pathway were genotyped and available for 1,538 participants. These SNPs were associated with reporting VMS > or =6 days compared with <6 days in the past 2 weeks using race/ethnicity-specific repeated measures logistic regression models. Participants were on average 46 years old at baseline. The prevalence of VMS reporting increased in all racial/ethnic groups from baseline to the sixth annual follow-up visit. After adjustment for covariates, several SNPs encoding genes responsible for estrogen metabolism and ERs were associated with decreased odds of reporting VMS, including the CYP1B1 rs1056836 GC genotype in African American women; 17HSD rs615942 TG, 17HSD rs592389 TG, and 17HSD rs2830 AG genotypes in Caucasian women; and the CYP1A1 rs2606345 AC genotype in Chinese women. We identified race/ethnicity-specific associations between VMS reporting and specific polymorphisms for sex steroid-metabolizing enzymes and sex steroid receptors. Clarification of the mechanisms of the associations and confirmation in other populations is warranted.

Polymorphisms in estrogen-metabolizing and estrogen receptor genes and the risk of developing breast cancer among a cohort of women with benign breast disease

Background

A cohort study was conducted to examine the role of genetic polymorphisms in three estrogen metabolizing enzymes (COMT, CYP1A1, CYP1B1) and the two estrogen receptors (ESR1, ESR2) in the progression of benign breast disease (BBD) to breast cancer.

Methods

Among participants in an ongoing cohort study, 1438 Caucasian women had a breast biopsy for BBD and were successfully genotyped for at least one of the polymorphisms examined in this study. Genotypes were determined using DNA extracted from blood specimens collected in 1989. Incident cases of breast cancer occurring subsequent to BBD diagnosis up to 2003 were identified through cancer registries.

Results

Among all participants, the ESR2 *5772G allele was associated with a significant decrease in the risk of breast cancer among women with BBD (Odds Ratio (OR) 0.38; 95% Confidence Interval (CI) 0.15, 0.96). Compared to the reference wild-type genotypes, marginally significant associations with the development of breast cancer were observed between carriers of the variant ESR1 – 104062T allele (OR 0.70, 95% CI 0.45, 1.09), the variant ESR2 *38A allele (OR 1.40; 95% CI 0.88, 2.25), and the variant CYP1B1 453Ser allele (OR 1.48, 95% CI 0.95, 2.32).

Conclusion

The results indicate that specific polymorphisms in the CYP1B1, ESR1, and ESR2 genes may play a role in progression of BBD to breast cancer among Caucasian women. Although additional studies are needed to confirm or refute our findings, these results suggest that genetic markers may aid in the identification of women who are at risk for progression of BBD to cancer.

Estrogen and progesterone receptor gene polymorphisms and sporadic breast cancer risk: A Spanish case-control study

Estrogens, and to a lesser extent progesterones, influence the proliferation, differentiation and physiology of breast tissue as well as the development and progression of breast cancer. Genetic variants in the steroid hormone receptor genes ESR1 and PGR (belonging to the nuclear receptor superfamily) could therefore modify sporadic breast cancer susceptibility. Two studies have shown a protective effect associated with variants in ESR1 in 2 distinct populations. We studied 4 single nucleotide polymorphisms (SNPs) in ESR1 and 4 in PGR in 550 consecutive and unrelated sporadic Spanish breast cancer patients and 564 healthy Spanish controls. We observed a dominant protective effect for the S10S variant in ESR1, with an estimated odds ratio (OR) of 0.75 (95% CI = 0.58-0.97; p = 0.03) although functional studies did not show changes in the RNA stability. A small subset of individuals carried a haplotype combination that corroborates this protection. No other SNP considered in either gene was found to be associated with sporadic breast cancer. Our results obtained in a European population confirm the protective role of the S10S variant in ESR1, previously reported in an Asian and a European-American population.