Estrogen receptor genotypes and haplotypes associated with breast cancer risk

Progesterone Receptor Gene Polymorphisms and Breast Cancer Risk

The objective of this systematic review was to investigate the association between polymorphisms in the progesterone receptor gene (PGR) and breast cancer risk. A search of PubMed, Scopus, and Web of Science databases was performed in November 2021. Study characteristics, minor allele frequencies, genotype frequencies, and odds ratios were extracted. Forty studies met the eligibility criteria and included 75 032 cases and 89 425 controls. Of the 84 PGR polymorphisms reported, 7 variants were associated with breast cancer risk in at least 1 study. These polymorphisms included an Alu insertion (intron 7) and rs1042838 (Val660Leu), also known as PROGINS. Other variants found to be associated with breast cancer risk included rs3740753 (Ser344Thr), rs10895068 (+331G/A), rs590688 (intron 2), rs1824128 (intron 3), and rs10895054 (intron 6). Increased risk of breast cancer was associated with rs1042838 (Val660Leu) in 2 studies, rs1824128 (intron 3) in 1 study, and rs10895054 (intron 6) in 1 study. The variant rs3740753 (Ser344Thr) was associated with decreased risk of breast cancer in 1 study. Mixed results were reported for rs590688 (intron 2), rs10895068 (+331G/A), and the Alu insertion. In a pooled analysis, the Alu insertion, rs1042838 (Val660Leu), rs3740753 (Ser344Thr), and rs10895068 (+331G/A) were not associated with breast cancer risk. Factors reported to contribute to differences in breast cancer risk associated with PGR polymorphisms included age, ethnicity, obesity, and postmenopausal hormone therapy use. PGR polymorphisms may have a small contribution to breast cancer risk in certain populations, but this is not conclusive with studies finding no association in larger, mixed populations.

ESR2 gene variants (rs1256049, rs4986938, and rs1256030) and their association with breast cancer risk

Background

Variants of the estrogen receptor b (ESR2) gene have been associated with different types of cancer. However, these associations have been inconsistent. We genotyped the ESR2 variants (rs1256049, rs4986938, and rs1256030) in breast cancer (BC) patients and in healthy women.

Results

The variants rs1256049 and rs4986938 in the ESR2 gene were not associated with risk susceptibility in BC patients. However, the rs1256030 variant had an association as a risk factor for BC patients when compared with controls and BC patients for the TT genotype (odds ratio (OR) 1.86, 95% confidence intervals (CI) [1.05-3.28], p = 0.042). In addition, differences were observed in patients and controls carrying the TT genotype under 50 years of age (OR 1.85, 95% CI [1.05-3.27], p = 0.043). Thus, evident differences showed the rs1256030 variant in patients with TT, TC, and TC+TT genotypes with: (1) Stage IV (OR 1.60, 95% CI [1.06-2.54], p = 0.033), and (2) Luminal A (OR 1.60, 95% CI [0.47-0.21], p = 0.041), as well as in BC carriers of the TT genotype with indices of cellular proliferative (Ki-67) elevated (>20%) and overweight (OR 1.67, 95% CI [0.85-3.28], p = 0.041), respectively. In BC HER2 with lymph node metastasis, the TT genotype was a protective factor (OR 0.38, 95% CI [0.18-0.78], p = 0.005). The identification of haplotypes included two common GAT as risk factors (OR 3.1, 95% CI [1.31-7.72], p = 0.011) and GGC as a protective factor (OR 0.7, 95% CI [0.60-0.97], p = 0.034). The haplogenotype GGGATC was a risk factor (OR 2.5, 95% CI [1.28-5.0], p = 0.008).

Conclusion

The variant rs1256030 (TT) of the ESR2 gene and haplotype GAT were associated with susceptibility to BC as risk factors in this sample from the Mexican population.

Congenital disorders of estrogen biosynthesis and action

Estrogens regulate pubertal development and reproductive function in women, spermatogenesis in men, and bone turnover and metabolic conditions in individuals of both sexes. Estradiol, the major estrogen in humans, is synthesized from testosterone by the action of aromatase and exerts its effects though binding to estrogen receptors. Germline loss- and gain-of-function variants in CYP19A1, the gene encoding aromatase, lead to aromatase deficiency and aromatase excess syndrome, respectively. Germline loss-of-function variants in ESR1, the gene encoding estrogen receptor α, are known to cause of estrogen insensitivity/resistance. In addition, rare variants in ESR1 and ESR2 have been implicated in various disease phenotypes. Clinical studies on these rare endocrine disorders provided clues to understand the biological functions of estrogens in the human body. This review introduces the genetic basis, phenotypes, and current management procedures of congenital disorders in estrogen biosynthesis and action.

Computational Functional Genomics-Based AmpliSeq™ Panel for Next-Generation Sequencing of Key Genes of Pain

The genetic background of pain is becoming increasingly well understood, which opens up possibilities for predicting the individual risk of persistent pain and the use of tailored therapies adapted to the variant pattern of the patient's pain-relevant genes. The individual variant pattern of pain-relevant genes is accessible via next-generation sequencing, although the analysis of all "pain genes" would be expensive. Here, we report on the development of a cost-effective next generation sequencing-based pain-genotyping assay comprising the development of a customized AmpliSeq™ panel and bioinformatics approaches that condensate the genetic information of pain by identifying the most representative genes. The panel includes 29 key genes that have been shown to cover 70% of the biological functions exerted by a list of 540 so-called "pain genes" derived from transgenic mice experiments. These were supplemented by 43 additional genes that had been independently proposed as relevant for persistent pain. The functional genomics covered by the resulting 72 genes is particularly represented by mitogen-activated protein kinase of extracellular signal-regulated kinase and cytokine production and secretion. The present genotyping assay was established in 61 subjects of Caucasian ethnicity and investigates the functional role of the selected genes in the context of the known genetic architecture of pain without seeking functional associations for pain. The assay identified a total of 691 genetic variants, of which many have reports for a clinical relevance for pain or in another context. The assay is applicable for small to large-scale experimental setups at contemporary genotyping costs.

A Possible Link of Genetic Variations in ER/IGF1R Pathway and Risk of Melanoma

The mechanism of gender disparity in cutaneous melanoma incidence remains unclear. Steroid hormones including estrogens have long been implicated in the course of melanoma, but the conclusion is controversial. Estrogen receptors (ERs) and insulin-like growth factor 1 receptor (IGF1R) show extensive crosstalk in cancer development, but how the ER/IGF1R network impacts melanoma is currently unclear. Here we studied the melanoma associations of selected SNPs from the ER/IGF1R network. Part of the International Genes, Environment, and Melanoma (GEM) cohort was used as a discovery set, and the Gene Environment Association Studies Initiative (GENEVA) dataset served as a validation set. Based on the associations with other malignant disease conditions, thirteen single nucleotide polymorphism (SNP) variants in ESR1, ESR2, IGF1, and IGF1R were selected for candidate gene association analyses. The rs1520220 in IGF1 and rs2229765 in IGF1R variants were significantly associated with melanoma risk in the GEM dataset after Benjamini-Hochberg multiple comparison correction, although they were not validated in the GENEVA set. The discrepancy may be caused by the multiple melanoma characteristics in the GEM patients. Further analysis of gender disparity was carried out for IGF1 and IGF1R SNPs in the GEM dataset. The GG phenotype in IGF1 rs1520220 (recessive model) presented an increased risk of melanoma (OR = 8.11, 95% CI: 2.20, 52.5, p = 0.006) in men but a significant opposite effect in women (OR = 0.15, 95% CI: 0.018, 0.86, p = 0.045). The AA genotype in IGF1R rs2229765 (recessive model) showed a significant protective effect in men (OR = 0.24, 95% CI: 0.07, 0.64, p = 0.008) and no effect in women. Results from the current study are warranted for further validation.

Evaluation of the epidemiological and prognosis significance of ESR2 rs3020450 polymorphism in ovarian cancer

AIM

To investigate the correlation between the polymorphism of estrogen receptor β gene (ESR2) rs3020450 and cancer susceptibility, and explore the epidemiological significance and the effect of ESR2 expression levels on the prognosis of ovarian cancer.

METHODS

Based on meta-analysis the association between ESR2 rs3020450 polymorphism and cancer susceptibility was estimated and a case-control design was used to verify this result in ovarian cancer. The epidemiological effect of ESR2 rs3020450 polymorphism was assessed by attributable risk percentage (ARP) and population attributable risk percentage (PARP). Kaplan Meier plotters were used to evaluate overall survival (OS) and progression-free survival (PFS) in ovarian cancer patients and GEPIA for the differential expression of ESR2 levels in ovarian cancer and adjacent normal tissues.

RESULTS

The pooled analysis indicated no significant correlation between the ESR2 rs3020450 polymorphism and the cancer susceptibility. In the stratified analysis by cancer types, significantly decreased risk was found in ovarian cancer (AG vs GG: OR = 0.73, 95%CI: 0.53-0.97, P = 0.03). Unconditional logistic regression results of case-control study in ovarian cancer observed significant differences in all comparisons (AG vs GG: OR = 0.81, 95%CI: 0.62-0.98, P = 0.04; AA vs GG: OR = 0.63, 95%CI: 0.42-0.92, P = 0.01 and AG + AA vs GG: OR = 0.73, 95%CI: 0.53-0.96, P < 0.001). Based on meta-analysis and case-control pooled results, ARP and PARP were evaluated respectively in allele (21.95% and7.97%), heterozygote (36.99% and 12.11%) and dominant model (36.84% and 12.97%) of rs3020450 polymorphism in ovarian cancer. The expression levels of ESR2 in normal tissues was significantly higher than that in cancer tissues (OV, Median, 4.7:0.21), and significant correlations were observed between high ESR2 expression levels and long OS (HR = 0.80, 95%CI: 0.70-0.92, P = 0.002) and PFS (HR = 0.767, 95%Cl: 0.67-0.88, P < 0.001).

CONCLUSION

Our results indicated that ESR2 rs3020450 polymorphism was associated with ovarian cancer risk from epidemiological perspective, and high ESR2 expression levels was associated with long survival in patients with ovarian cancer.

Genome-wide haplotype association study identifies risk genes for non-small cell lung cancer

Lung cancer is the leading cause of cancer-related death worldwide. Most lung cancer is non-small cell lung cancer (NSCLC), in which malignant cells form in the lung epithelium. Mutations in multiple genes and environmental factors both contribute to NSCLC, and although some NSCLC susceptibility genes have been characterized, the pathogenesis of this disease remains unclear. To identify genes conferring NSCLC risk and determine their associated pathological mechanism, we combined genome-wide haplotype associated analysis with gene prioritization using 224,677 SNPs in 37 NSCLC cell lines and 116 unrelated European individuals. Five candidate genes were identified: ESR1, TGFBR1, INSR, CDH3, and MAP3K5. All of these have previously been implicated in NSCLC, with the exception of CDH3, which can therefore be considered a novel indicator of NSCLC risk. Functional annotation confirmed the relationship between these five genes and NSCLC. Our findings are indicative of the underlying pathological mechanisms of NSCLC and provide information to support future directions in diagnosing and treating NSCLC.

Differential association of ESR1 and ESR2 gene variants with the risk of breast cancer and associated features: A case-control study

BACKGROUND

Estrogen is key to breast cancer pathogenesis, and acts by binding its receptor (ER), which exists as ERα and ERβ, encoded by ESR1 and ESR2 genes, respectively. Studies that investigated the association of ESR1 and ESR2 variants with breast cancer yielded mixed outcome, and ethnic contribution was proposed. We evaluated the association between ESR1 and ESR2 variants and breast cancer and associated features in Tunisian women.

METHODS

Retrospective case-control study involving 207 female breast cancer patients, and 284 control women. Genotyping was done by real-time PCR.

RESULTS

Minor allele frequencies (MAF) of tagging SNPs rs2234693 and rs3798577 (ESR1) were significantly higher, while MAF of rs1256049 (ESR2) was significantly lower in breast cancer patients vs.

CONTROLS

Patients carrying rs3798577 genotypes had higher risk, while rs1256049 genotype carriers had reduced risk of breast cancer. The association of ESR1 and ESR2 gene variants with breast cancer depended on ER and Her-2 status. ESR1 rs3798577 and ESR2 rs1256049 were associated with breast cancer in ER-positive cases, and ESR1 rs2234693, and rs3798577 were associated with breast cancer in Her-2-negative cases, while the association of ESR2 rs1256049 with breast cancer was seen in Her-2 positive cases. Haploview analysis identified 4-locus ESR1 haplotypes that were positively (CGTT, TACC, and TACT), and negatively (CGTC) associated with breast cancer. No ESR2 haplotypes associated with breast cancer were identified.

CONCLUSION

ESR1 alleles and genotypes, and specific 3-locus ESR1 haplotypes are related with increased breast cancer susceptibility in Tunisian women. However, ESR2 variant and specific 1-locus ESR1 haplotype have a protective effect.

Progesterone Receptor (PGR) Gene Variants Associated with Breast Cancer and Associated Features: a Case-Control Study

Insofar as altered estrogen receptor-progesterone receptor (PR) expression contribute to breast cancer pathogenesis, previous studies examined the association of genetic variation in PR gene (PGR) with breast cancer, but with mixed outcome. We evaluated the association between PGR variants, and breast cancer and associated features. A retrospective case-control study involving 183 female breast cancer patients, and 222 control women. PGR genotyping was done by real-time PCR. Minor allele frequencies of rs1042838, rs590688, and rs10895068 PGR gene polymorphisms were significantly higher in breast cancer patients compared to controls. Patients carrying rs1042838 G/T, rs590688 C/C, and rs10895068 G/A genotypes had higher risk of breast cancer, while carriage of rs3740753 G/G genotype was associated with marginal reduction in breast cancer risk. In addition, carriage of rs1042839, rs3740753, and rs10895068 minor allele was associated with Her2 status, while rs3740753 and rs10895068 were associated with effective hormone replacement therapy. Furthermore, carriage of rs10895068 minor allele in breast cancer women were also associated with age at first pregnancy, hormone receptor (RH) status, and previous use of oral contraceptives. PGR haploview analysis documented moderate-strong linkage disequilibrium (non-random association of alleles at different loci) between 7 of the 8 tested PGR SNPs, thus allowing construction of 7-locus PGR haplotypes. Two haplotypes, ATGCCGA and GTGCCGA, both containing rs590688, were positively associated with breast cancer, thus assigning a breast cancer-susceptible nature to these haplotypes. PGR rs1042838, rs590688, and rs10895068, and ATGCCGA and GTGCCGA haplotypes are related with increased breast cancer susceptibility in Tunisian women.

Relationship of oestrogen receptor alpha gene polymorphisms with risk for benign prostatic hyperplasia and prostate cancer in Chinese men

The relationship of oestrogen receptor with benign prostatic hyperplasia (BPH) and prostate cancer (PC) is not clear at present. This study aimed to investigate the molecular mechanism underlying the occurrence and development of BPH and prostate.Two hundred forty-four PC cases, 260 BPH patients, and 222 healthy men were recruited from Han people in China, and the oestrogen receptor alpha (ESRα) gene polymorphism (rs2234693 [PvuII] and rs9340799 [XbaI]) on intron 1 was determined. The relationship of gene polymorphism with PC and BPH was evaluated with Logistic regression, and the linkage disequilibrium and haplotyping were assessed with SHEsis software.The risk for PC in BPH patients with PvuII C allele was higher (OR = 1.437, 95% CI: 1.110-1.859), but the differentiation degree of cancer cells was relatively better in PC patients with PvuII C allele (OR = 0.419, 95% CI: 0.285-0.616), and most of them are circumscribed (OR = 0.706, 95% CI: 0.485-1.02). There was significant linkage disequilibrium between PvuII and XbaI. The genotype TTAG not only induced BPH (OR = 6.260, 95% CI: 1.407-27.852), but increased the risk for PC (OR = 6.696, 95% CI: 1.504-29.801). However, the genotype TTAG in BPH patients had no relationship with the risk for PC (P > 0.05). Furthermore, men with haplotype TG were more likely to suffer PC (OR = 9.168, 95% CI: 2.393-35.119), but men with haplotype TA and enlarged prostate had a low risk for PC (OR = 0.708, 95% CI: 0.551-0.912).These results show the relationship between ESRα gene polymorphism and susceptibility to PC and BPH in Chinese men, and the ethnic and regional difference as well.

ESR1 and PGR polymorphisms are associated with estrogen and progesterone receptor expression in breast tumors

Hormone receptor-positive (HR+) breast cancers express the estrogen (ERα) and/or progesterone (PgR) receptors. Inherited single nucleotide polymorphisms (SNPs) in ESR1, the gene encoding ERα, have been reported to predict tamoxifen effectiveness. We hypothesized that these associations could be attributed to altered tumor gene/protein expression of ESR1/ERα and that SNPs in the PGR gene predict tumor PGR/PgR expression. Formalin-fixed paraffin-embedded breast cancer tumor specimens were analyzed for ESR1 and PGR gene transcript expression by the reverse transcription polymerase chain reaction based Oncotype DX assay and for ERα and PgR protein expression by immunohistochemistry (IHC) and an automated quantitative immunofluorescence assay (AQUA). Germline genotypes for SNPs in ESR1 (n = 41) and PGR (n = 8) were determined by allele-specific TaqMan assays. One SNP in ESR1 (rs9322336) was significantly associated with ESR1 gene transcript expression (P = 0.006) but not ERα protein expression (P > 0.05). A PGR SNP (rs518162) was associated with decreased PGR gene transcript expression (P = 0.003) and PgR protein expression measured by IHC (P = 0.016), but not AQUA (P = 0.054). There were modest, but statistically significant correlations between gene and protein expression for ESR1/ERα and PGR/PgR and for protein expression measured by IHC and AQUA (Pearson correlation = 0.32-0.64, all P < 0.001). Inherited ESR1 and PGR genotypes may affect tumor ESR1/ERα and PGR/PgR expression, respectively, which are moderately correlated. This work supports further research into germline predictors of tumor characteristics and treatment effectiveness, which may someday inform selection of hormonal treatments for patients with HR+ breast cancer.

A Meta-Analysis of the Association between ESR1 Genetic Variants and the Risk of Breast Cancer

Background

Single nucleotide polymorphisms (SNPs) in the estrogen receptor gene (ESR1) play critical roles in breast cancer (BC) susceptibility. Genome-wide association studies have reported that SNPs in ESR1 are associated with BC susceptibility; however, the results of recent studies have been inconsistent. Therefore, we performed this meta-analysis to obtain more accurate and credible results.

Methods

We pooled published literature from PubMed, EMBASE, and Web of Science and calculated odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of associations using fixed effects models and random effects models. Twenty relevant case-control and cohort studies of the 3 related SNPs were identified.

Results

Three SNPs of the ESR1 gene, rs2077647:T>C, rs2228480:G>A and rs3798577:T>C, were not associated with increased BC risk in our overall meta-analysis. Stratified analysis by ethnicity showed that in Caucasians, the rs2228480 AA genotype was associated with a 26% decreased risk of BC compared with the GG genotype (OR = 0.740, 95% CI: 0.555–0.987). The C allele of the rs3798577:T>C variant was associated with decreased BC risk in Asians (OR = 0.828, 95% CI: 0.730–0.939), while Caucasians with this allele were found to experience significantly increased BC risk (OR = 1.551, 95% CI: 1.037–2.321). A non-significant association between rs2077647 and BC risk was identified in all of the evaluated ethnic populations.

Conclusion

Rs3798577 was associated with an increased risk of BC in Caucasian populations but a decreased risk in Asians. Rs2228480 had a large protective effect in Caucasians, while rs2077647 was not associated with BC risk.

Radiation-induced apoptosis varies among individuals and is modified by sex and age

PURPOSE

Although there are considerable data on mechanisms of radiation-induced apoptosis in vitro and in animal models, little is known about functional variation in these pathways in humans. We sought to develop a tractable system to evaluate this.

MATERIALS AND METHODS

Peripheral blood mononuclear cells were isolated from 90 healthy volunteers, divided into two aliquots, one irradiated with a 5 Gy dose and the other sham-treated (0 Gy), and assessed for damage-induced apoptosis after 24 hours. To investigate reproducibility, 10 individuals spanning the entire radiation-induced apoptotic range were tested three times each, with 3-6 months between replicates.

RESULTS

We observed surprising heterogeneity in apoptosis among individuals, ranging from 21-62%. Biological replicates from a single individual, however, were completely concordant, suggesting the variability observed across individuals is not the result of stochastic or short-term effects. We found significantly higher radiation-induced apoptosis in males than in females (Mean: 41.0% vs. 30.7%; p < 3.5 × 10(-7)). Moreover, advancing age was associated with decreasing radiation-induced apoptosis in males (p = 0.01) but not females (p = 0.82).

CONCLUSIONS

Our results provide evidence that the function of cellular pathways crucial for stress-induced apoptosis varies by sex and could decline with age in humans.

Icb-1 gene polymorphism rs1467465 is associated with susceptibility to ovarian cancer

In this study, we tested the hypothesis that single nucleotide polymorphisms (SNPs) of differentiation-associated human gene icb-1 (C1orf38) may be associated with ovarian cancer susceptibility. For this purpose, we compared the genotype and allele frequencies of the SNPs rs1467465 and rs12048235 in a group of 184 ovarian cancer patients with a control group of 184 age- and gender-matched women without any malignancy. Genotype-phenotype association revealed that A allele of SNP rs1467465 was more frequent in ovarian cancer patients than in the control group (0.40 vs. 0.33, OR 1.37, 95% CI 1.013-1.853, p = 0.04). After analysis of allele positivity we observed that A-positive genotypes were more frequent in the ovarian cancer group (0.65 vs. 0.53, OR 1.63, 95% CI 1.072-2.483, p = 0.02). Furthermore, the heterozygous genotype of rs1467465 was found to be more frequent in the patients group (0.50 vs. 0.41, OR 1.63, 95% CI 1.045-2.045, p = 0.03). No significant results were obtained with regard to SNP rs1204823. Our data suggest, that SNP rs1467465 of human gene icb-1 might affect susceptibility to ovarian cancer.

Polymorphisms in the promoter region of estrogen receptor β gene in endometrial cancer

INTRODUCTION

The development of endometrial cancer is known to be affected by estrogens. Thus, genetic variations like single nucleotide polymorphisms (SNPs) in genes involved in estrogen biosynthesis, metabolism, and signal transduction might affect risk for endometrial cancer. In this study, we tested the hypothesis that polymorphisms in the promoter of ESR2 gene may be associated with susceptibility to this disease.

METHODS

We compared the frequency of three SNPs in the promoter region of ESR2 gene (rs2987983, rs3020450, and rs3020449) in 135 women with endometrial cancer and 135 healthy women serving as controls by means of allele-specific tetra-primer PCR.

RESULTS

Regarding allele frequency, allele positivity or genotype frequencies of these SNPs we did not observe any significant difference between healthy women and women with endometrial cancer.

CONCLUSION

Our data clearly suggest that the tested SNPs in the promotor region of human ESR2 gene are not associated with the development of endometrial cancer.

Association of progesterone receptor gene (PGR) variants and breast cancer risk in African American women

Prolonged exposure to combined hormone replacement therapy (estrogen plus progestin) increases a woman's risk of breast cancer, whereas estrogen-only hormone replacement therapy does not. This suggests that progesterone may play a role in breast carcinogenesis. Association studies have reported inconsistent relationships between progesterone receptor gene variants and breast cancer. A population-based case-control study in three counties of the Philadelphia Metropolitan area was undertaken. We evaluated 8 PGR candidate SNPs and 18 PGR tagging SNPS in 487 breast cancer cases and 843 controls using multivariable logistic regression with adjustment for combined hormone replacement therapy use. Separate analyses were conducted for European Americans (EA: 399 cases, 490 controls) and African Americans (AA: 88 cases, 353 controls). In EAs, no significant associations were observed with the investigated PGR variants. In AAs, two tagging SNPs (rs590688 and rs10895054) were statistically significantly associated with breast cancer. For rs590688, each addition of the C allele was protective compared to the G allele (OR = 0.56, 95 % CI 0.39-0.82, p value 0.003, corrected p value 0.03). For rs10895054, each addition of the T allele increased the risk of breast cancer compared to the A allele nearly threefold (OR = 2.9, 95 % CI 1.47-6.02, p value 0.002, corrected p value 0.04). Three haplotype blocks, all containing rs590688, were found to be significantly associated with breast cancer risk. Environmental exposures, namely parity and obesity modified the effect of both SNPs on breast cancer risk in EA. This is the first study to find an association between two PGR variants and breast cancer in AA women. These results suggest that studies of PGR variants in other non-White populations may reveal additional cancer associations of interest.

Significance of rs1271572 in the estrogen receptor beta gene promoter and its correlation with breast cancer in a southwestern Chinese population

Background

To characterize single nucleotide polymorphisms (SNPs) within the promoter region of the estrogen receptor beta (ERβ) gene and to analyze the association of ERβ SNPs with susceptibility to breast cancer. Genotype frequencies of five SNPs (rs3020449, rs3020450, rs2987983, rs1271572 and rs1887994) in the promoter region of the ERβ gene in 873 women with breast cancer, 645 women with fibroadenoma and 700 healthy women were determined using an allele-specific tetra-primer polymerase chain reaction (PCR). Kaplan-Meier survival analysis was performed to evaluate the association of selected rs1271572 with prognosis in breast cancer. Electrophoretic mobility-shift assays were conducted to explore the binding of SNP rs1271572 containing probes to transcriptional factor Ying Yang 1 (YY1).

Results

Women with the homozygous TT genotype of rs1271572 had a significantly higher risk in developing breast cancer. Breast cancer patients with the TT genotype of rs1271572 had lower five-year survival rates than those with other genotypes and were more likely to suffer brain metastases. The rs1271572 G→T SNP abrogated YY1 binding and reduced the transcription activity of the promoter 0 N in the ERβ gene in vitro.

Conclusions

TT genotype of rs1271572 is associated with increased risk for breast cancer in Chinese women and is associated with unfavored prognosis in Chinese breast cancer patients. TT genotype of rs1271572 inhibited expression of ERβ gene by down regulating transcriptional activity of the promoter 0 N in the ERβ gene. Our data revealed that the TT genotype of rs1271572 resulted in loss of the YY1 binding site and reduced the transcription activity of the promoter 0 N in the ERβ gene.

Genetic variation in ESR2 and estrogen receptor-beta expression in lung tumors

OBJECTIVE

To investigate the association between inherited variation in the estrogen receptor beta (ERβ) gene (ESR2) and ERβ lung tumor expression, a phenotype that possibly affects survival differently in men and women.

METHODS

We genotyped 135 lung cancer patients for 22 ESR2 single nucleotide polymorphisms (SNPs) and measured nuclear and cytoplasmic ERβ expression by immunohistochemistry (IHC) in their primary lung tumor. Distributing Allred ERβ IHC scores according to ESR2 genotype classified under a dominant genetic model, we used rank sum tests to identify ESR2 SNPs significantly associated (p<0.05) with ERβ expression.

RESULTS

35%, 35%, and 29% of lung tumors showed no/low (Allred<6), intermediate (Allred 6-7), and maximal (Allred 8) cytoplasmic ERβ expression, whereas 13%, 27%, and 60% showed no/low, intermediate, and maximal nuclear ERβ expression. For SNPs rs8021944, rs1256061 and rs10146204, ERβ expression was higher according to the rank sum test in lung tumors from patients with at least one minor allele. For each of these three SNPs, the odds of maximal (Allred 8) relative to no/low (Allred<6) ERβ expression was 3-fold higher in tumors from patients with at least one minor allele than in tumors from patients homozygous for the common allele.

CONCLUSION

Inherited variability in ESR2 may determine ERβ lung tumor expression.

Comparison of genetic variation of breast cancer susceptibility genes in Chinese and German populations

Genome-wide association studies (GWAS) identified several genetic risk factors for breast cancer, however, most of them were validated among women of European ancestry. This study examined single-nucleotide polymorphisms (SNPs) contributing to breast cancer in Chinese (984 cases and 2206 controls) and German (311 cases and 960 controls) populations. Eighteen SNPs significantly associated with breast cancer, previously identified in GWAS were genotyped. Twelve SNPs passed quality control and were subjected to statistical analysis. Seven SNPs were confirmed to be significantly associated with breast cancer in the Chinese population, reflecting three independent loci (ESR1, FGFR2, TOX3) and five of these were also confirmed in the German population. The strongest association was identified for rs2046210 in the Chinese (odds ratio (OR)=1.42, 95% confidence interval (CI)=1.28-1.59, P=1.9 × 10(-10)) and rs3803662 in the German population (OR=1.43, 95% CI=1.17-1.74, P=4.01 × 10(-4)), located upstream of the ESR1 and TOX3 gene, respectively. For the first time, rs3757318 at 6q25.1, located next to the gene encoding estrogen receptor α (ESR1) was found to be strongly associated with breast cancer (OR=1.33, 95% CI=1.18-1.49, P=1.94 × 10(-6)) in the Chinese population. The frequency of this variant was markedly lower in the German population and the association was not significant. Despite the genetic differences, essentially the same risk loci were identified in the Chinese and the German populations. Our study suggested the existence of common genetic factors as well as disease susceptibility differences for breast cancer in both populations and highlighted the importance of performing comparison analyses for disease susceptibility within ethnic populations.

ESR1 polymorphisms, daily hassles, anger expression, and depressive symptoms in adolescent boys and girls

Studies reporting associations between genetic factors and mood-related traits have often been criticized (i) for failing to take into account the role of the social environment in which individuals act and (ii) for not maintaining a 'transparent narrative connection' between genes and outcomes. In a sample of adolescents, we analyzed whether PvuII and XbaI, two polymorphisms on the ESR1 (Estrogen Receptor Gene α) were related to depressive symptoms, and considered whether daily hassles moderated this relationship and whether anger expression style mediated this relationship. Analyses suggested that ESR1 polymorphisms are relevant to the intra-sexual variability in depressive symptoms in boys and that the experience of daily hassles moderated this relationship. No such relationships were found in girls. Additionally, ESR1 polymorphisms are related to anger expression styles in girls. Anger-related variables, however, did not mediate the relationship between ESR1 polymorphisms and depressive symptoms, in boys nor in girls.

Given breast cancer, is fat better than thin? Impact of the estrogen receptor beta gene polymorphisms

The role of estrogen receptor beta (ERβ) in breast cancer has been investigated since its identification in 1996. Studies based on protein expression have indicated that ERβ is a favorable prognostic marker. Further, ERβ expression is lower in obese breast cancer patients. Fewer studies have focused on the prognostic impact of ERβ polymorphisms. Therefore, we analyzed the associations between four previously identified haplotype tagging single nucleotide polymorphisms (htSNPs), associated haplo- and diplotypes, and breast cancer-free survival according to body constitution. The patient cohort included 634 women from the prospective breast cancer and blood study (BC Blood study, Sweden) with a median follow-up of 4.92 years. Four htSNPs (i.e., rs4986938, rs1256049, rs1256031, rs3020450) in the ESR2 gene and the correlating haplo- and diplotypes were analyzed and correlated to selected patient and tumor characteristics and to disease-free survival, including stratification for BMI. Based on the four htSNPs, seven haplotypes and eight diplotypes were identified. The patient and tumor characteristics were well-balanced across all geno- and haplotypes. Disease-free survival differed according to rs4986938 and rs1256031 (Log-Rank P = 0.045 and P = 0.041, respectively) and the number of haplotype copies of the wildtype CCGC and TCAC (Log-Rank P = 0.027 and P = 0.038, respectively). In the survival analyses stratified for BMI, significant survival differences between alleles were observed among overweight women (rs4986938 and rs1256031 with Log-Rank P = 0.001 and P = 0.001, respectively). The BMI-stratified survival analyses based on haplotypes showed shorter disease-free survival for overweight women with null copies of CCGC (Log-Rank P = 0.001) and for overweight women with any TCAC copy (Log-Rank P < 0.0001). Markedly impaired disease-free survival was found for genotypes in two out of four ESR2 htSNPs and for two haplotypes. ESR2 polymorphisms seem to divide patients into good and poor survivors based on BMI, stressing the need of taking host factors into consideration in the evaluation of prognostic markers.

Association of estrogen receptor alpha (ERα) gene polymorphisms with endometrial thickness and lipid profile in women with breast cancer treated with aromatase inhibitors

Aromatase inhibitors (AIs) provide an alternative to tamoxifen as an adjuvant therapy for post-menopausal, hormone-receptor positive breast cancer patients. The aim of the present study was to evaluate the effect of PvuII and XbaI polymorphisms of the ERα gene at ΑΙs treatment's adverse effects in post-menopausal women with breast cancer. The study included 87 post-menopausal women with ER-positive breast cancer treated with AIs and 80 healthy controls. The overall presence of ERα polymorphisms in all women with breast cancer was not different from the healthy controls. Endometrial thickness under AIs treatment was reduced from (mean value ± SD) 6,404 ± 2,901 mm to 3,666 ± 1,4656 mm. Moreover, the AA XbaI genotype was associated with greater reduction in endometrial thickness during therapy with AIs (p = 0.005). The presence of the CC PvuII and the AA XbaI genotypes were associated with elevated LDL levels and elevated triglycerides. In conclusion, the results of the present study showed that the genotype of women with breast cancer under AIs treatment might influence treatment's adverse effects, as, the presence of the CC PvuII and the AA XbaI genotypes of the ERα were associated with elevated LDL and triglycerides serum levels, while the AA XbaI genotype was associated with a greater reduction in endometrial thickness.

Rare copy number variants observed in hereditary breast cancer cases disrupt genes in estrogen signaling and TP53 tumor suppression network

Breast cancer is the most common cancer in women in developed countries, and the contribution of genetic susceptibility to breast cancer development has been well-recognized. However, a great proportion of these hereditary predisposing factors still remain unidentified. To examine the contribution of rare copy number variants (CNVs) in breast cancer predisposition, high-resolution genome-wide scans were performed on genomic DNA of 103 BRCA1, BRCA2, and PALB2 mutation negative familial breast cancer cases and 128 geographically matched healthy female controls; for replication an independent cohort of 75 similarly mutation negative young breast cancer patients was used. All observed rare variants were confirmed by independent methods. The studied breast cancer cases showed a consistent increase in the frequency of rare CNVs when compared to controls. Furthermore, the biological networks of the disrupted genes differed between the two groups. In familial cases the observed mutations disrupted genes, which were significantly overrepresented in cellular functions related to maintenance of genomic integrity, including DNA double-strand break repair (P = 0.0211). Biological network analysis in the two independent breast cancer cohorts showed that the disrupted genes were closely related to estrogen signaling and TP53 centered tumor suppressor network. These results suggest that rare CNVs represent an alternative source of genetic variation influencing hereditary risk for breast cancer.

Recognition of a C-C mismatch in a DNA duplex using a fluorescent small molecule with application for "off-on" discrimination of C/G mutation

The fluorescent small molecule 2-amino-7-methyl-1,8-naphthyridine (AMND) can selectively bind to a cytosine (C) at a C-C mismatch in double-stranded DNA (dsDNA). The interactions between AMND and C-C mismatch-containing dsDNA were investigated by measuring ultraviolet (UV) absorption as a function of temperature to obtain melting curves as well as circular dichroism and fluorescence spectra. Results show that AMND strongly stabilizes C-C mismatch-containing dsDNA, whereas fully matched duplexes are not stabilized under the same conditions. The fluorescence of AMND was efficiently quenched when it was bound to a C-C mismatch in dsDNA. Binding constants (K(11)), obtained by fluorescence titration, were 1.2 × 10(5) M(-1). Although sensing functions depend on the sequences flanking the mismatch site, the change in AMND fluorescence intensity can be utilized to detect the C-C mismatch-containing dsDNA. Accordingly, discrimination of the C/G mutation in the model sequence (PGR gene rs1255998) was achieved by visualizing fluorescence of AMND. A probe DNA molecule was designed to contain a C opposite the C/G base in the target DNA, and this probe was used to hybridize the target DNA. The fluorescence of AMND was "on" for a C-G match, while the fluorescence was "off" for a C-C mismatch. This assay is simple and does not require DNA labeling.

Estrogen receptor-Beta variants are associated with increased risk of Alzheimer's disease in women with down syndrome

BACKGROUND/AIMS

Genetic variants that affect estrogen activity may influence the risk of Alzheimer's disease (AD). We examined the relation of polymorphisms in the gene for the estrogen receptor-beta (ESR2) to the risk of AD in women with Down syndrome.

METHODS

Two hundred and forty-nine women with Down syndrome, 31-70 years of age and nondemented at baseline, were followed at 14- to 18-month intervals for 4 years. Women were genotyped for 13 single-nucleotide polymorphisms (SNPs) in the ESR2 gene, and their association with AD incidence was examined.

RESULTS

Among postmenopausal women, we found a 2-fold increase in the risk of AD for women carrying 1 or 2 copies of the minor allele at 3 SNPs in introns seven (rs17766755) and six (rs4365213 and rs12435857) and 1 SNP in intron eight (rs4986938) of ESR2.

CONCLUSION

These findings support a role for estrogen and its major brain receptors in modulating susceptibility to AD in women.

A systematic review of the relationship between polymorphic sites in the estrogen receptor-beta (ESR2) gene and breast cancer risk

The estrogen signal is mediated by the estrogen receptor (ER). The specific role of ER-beta, a second ER, in breast carcinogenesis is not known. A number of association studies have been carried out to investigate the relationship between polymorphic sites in the ESR2 gene and breast cancer risk, however, the results are inconsistent. We searched PubMed, Medline, and Web of Science database (updated to 10 January 2010) and identified 13 relevant case-control studies, and approximately 28 single-nucleotide polymorphisms (SNPs) and one micro-satellite marker were reported in the literature. The median number of study subjects was 776 (range 158-13,550). Three genetic variants [(CA)n, rs2987983, and rs4986938] showed significant overall associations with breast cancer, and rs4986938 was reported twice. Because rs4986938 and rs1256049 were the most extensively studied polymorphisms, we subsequently conducted a meta-analysis to evaluate their relationship with breast cancer risk (9 studies of 10,837 cases and 16,021 controls for rs4986938; 8 studies of 11,652 cases and 15,726 controls for rs1256049). For rs4986938, the women harboring variant allele seemed to be associated with a decreased risk either in the dominant model [pooled OR = 0.944, 95% confidence interval (95% CI) 0.897-0.993, fixed-effects] or in the co-dominant model (AG vs. GG) (OR = 0.944, 95% CI 0.895-0.997, fixed-effects). rs1256049 was not associated with breast cancer risk in any model. Five studies had investigated the effect of haplotypes in the ESR2 gene on breast cancer risk, and four of them had positive outcomes. In summary, the present systematic review suggests that SNP rs4986938 as well as haplotypes in the ESR2 gene might be associated with breast cancer. The need for additional studies examining these issues seems of vital importance.

Analysis of single nucleotide polymorphisms in the 3' region of the estrogen receptor 1 gene in normal and cryptorchid Miniature Dachshunds and Chihuahuas

This study was performed to examine the distribution of single nucleotide polymorphisms (SNPs) and estimated haplotypes in the canine estrogen receptor (ER) alpha gene (ESR1) and the association of them with different phenotypes of cryptorchidism (CO) in Miniature Dachshunds and Chihuahuas. Forty CO and 68 normal dogs were used, and CO was classified into unilateral (UCO; n=33) and bilateral CO (BCO; n=5) or into abdominal (ACO; n=16) and inguinal CO (ICO; n=22). Thirteen DNA fragments located in the 70-kb region at the 3' end of ESR1 were amplified by PCR and sequenced to examine 13 SNPs (#1-#13) reported in a canine SNP database. Ten SNPs (#1-#4, #7, #8, #10-#13) were not polymorphic, and 5 new SNPs (#14-#18) were discovered. A common haplotype block in normal, CO and CO phenotypes was identified for an approximately 20-kb region encompassing 4 SNPs (#14-#17). Allele, genotype and haplotype frequencies in CO without classification by phenotype and also in UCO, ACO and ICO phenotypes were not statistically different from the normal group. Significant differences in genotype frequencies and homozygosity for the estimated GTTG haplotype within the block were observed in BCO compared with the normal group, although the number of BCO animals was small. Our results demonstrate that the examined SNPs and haplotypes in the 3' end of canine ESR1 are not associated with unilateral, abdominal and inguinal CO phenotypes and CO per se in Miniature Dachshunds and Chihuahuas. Further studies are necessary to suggest a clear association between the ESR1 SNPs and bilateral CO in dogs.

Estrogen receptor alpha polymorphisms and the risk of malignancies

Estrogens represent risk factors for endocrine-related cancers and play also an important role in the development and progression of other malignancies. In order to analyze the associations between estrogen receptor gene alpha polymorphisms and cancers susceptibility, we genotyped six single nucleotide polymorphisms (SNPs) in 163 Caucasian cancer patients--103 breast cancers and 60 other malignancies (colorectal, bladder, hepatocellular carcinoma and acute myeloid leukemia)--and 114 healthy controls using hybridization probes. We performed Armitage`s association trend-test to evaluate the risk. Linkage disequilibrium (LD) was assessed for each pair of markers. The genotypes CC and CT of rs3798577 were significantly associated with the cancers risk (p-trend breast = 4 × 10(-5); p-trend cancers = 1 × 10(-5)); in discrepancy with breast cancer where the C-allele represented the risk allele, for bladder, hepatocellular carcinomas and leukemia, the T allele seems to confer susceptibility. The minor G allele of rs1801132 was protective in our cases (p = 1 × 10(-4)); for rs2228480, the heterozygous frequency was higher for cancer groups (p = 0.03); the SNP pairs rs2228480&rs3798577 and rs2234693&rs9340799 were in low LD; the haplotypes T-A of rs2234693&rs9340799 and G-C of rs2228480&rs3798577 showed a trend to be higher represented in breast cancers; T allele of rs2234693 was higher expressed in breast, colon cancers and leukemia; rs2077647 was associated with colon (p = 0.008, C-risk allele) and bladder (p = 0.01, T-risk allele) cancers. We concluded that ESR1 polymorphisms may have distinct impact in carcinogenesis and further genotyping will establish whether these findings remain significant in larger cohorts.

Estrogen receptor beta gene polymorphisms and susceptibility to uterine fibroids

Uterine fibroids are the most common benign tumors of the female genital tract. Steroid hormones, especially estradiol and progesterone, play an important role in the pathobiology of this frequent disease. Recent studies suggested that both expression levels and polymorphisms of estrogen receptor (ER) alpha and beta might affect development of uterine fibroids. In this study, we tested whether single nucleotide polymorphisms (SNPs) in the promoter of estrogen receptor beta gene (ESR2) are associated with susceptibility to uterine fibroids. For this purpose, we compared the frequency of three SNPs in the promoter region of ESR2 gene (rs2987983, rs3020450 and rs3020449) in 101 women with uterine fibroids and 102 healthy women serving as controls by means of allele-specific tetra-primer polymerase chain reaction (PCR). Regarding allele frequency, allele positivity, genotype and haplotype frequencies of these SNPs we did not observe any significant difference between healthy women and women with uterine fibroids. In conclusion, our data clearly suggest that the tested SNPs in the promotor region of human ESR2 gene are not associated with the development of uterine fibroids.

Lack of association between oestrogen receptor polymorphisms and change in bone mineral density with tamoxifen therapy

Background:

Tamoxifen, a selective oestrogen receptor (ER) modulator, increases bone mineral density (BMD) in postmenopausal women and decreases BMD in premenopausal women. We hypothesised that inherited variants in candidate genes involved in oestrogen signalling and tamoxifen metabolism might be associated with tamoxifen effects in bone.

Methods:

A total of 297 women who were initiating tamoxifen therapy were enrolled in a prospective multicentre clinical trial. Lumbar spine and total hip BMD values were measured using dual-energy X-ray absorptiometry (DXA) at baseline and after 12 months of tamoxifen therapy. Single-nucleotide polymorphisms (SNPs) in ESR1, ESR2, and CYP2D6 were tested for associations in the context of menopausal status and previous chemotherapy, with a mean percentage change in BMD over 12 months.

Results:

The percentage increase in BMD was greater in postmenopausal women and in those patients who had been treated with chemotherapy. No significant associations between tested SNPs and either baseline BMD or change in BMD with 1 year of tamoxifen therapy were detected.

Conclusion:

The evaluated SNPs in ESR and CYP2D6 do not seem to influence BMD in tamoxifen-treated subjects.

Potentially functional polymorphisms in ESR1 and breast cancer risk: a meta-analysis

Estrogen exposure is a central risk factor in the development of breast cancer. Estrogen receptor alpha (coded by ESR1) is the key mediator of estrogen response in mammary tissue. Genetic changes altering the expression of ESR1 is likely to affect breast cancer susceptibility. Since the identification of several potentially functional polymorphisms in ESR1 (rs2234693, rs9340799, rs1801132, rs3798577, rs2228480), molecular epidemiological studies were conducted in recent years to evaluate the association between polymorphisms and breast cancer risk in diverse populations. However, the results remain conflicting rather than conclusive. This current analysis on 10,300 breast cancer cases and 16,620 controls on rs2234693 showed a borderline significant decreased breast cancer risk for CC and CC/CT carriers (CC vs. TT: OR, 0.92, 95% CI, 0.86-0.99; CC/CT vs. TT: OR, 0.95, 95% CI, 0.89-1.00). Variant genotypes of the rs1801132 polymorphism were also associated with a decreased breast cancer risk in a dominant model in 5,649 cases and 6,856 controls (GG/GC vs. CC: OR, 0.92, 95% CI, 0.85-0.99). These results suggest that potentially functional ESR1 polymorphisms may play a low penetrance role in breast cancer susceptibility. SNPs rs9340799, rs3798577, rs2228480, and rs2077647 in ESR1 were not causative SNPs. SNPs rs2747648, rs1062577, and rs3020314 were recommended in further association studies and functional evaluations.

Effects of two common polymorphisms in the 3' untranslated regions of estrogen receptor beta on mRNA stability and translatability

BACKGROUND

The present study represents the first attempt to functionally characterize two common single nucleotide polymorphisms (SNPs) in the 3'untranslated regions (3'UTRs) of estrogen receptor beta (ERbeta), focusing on the differences between alleles with regard to mRNA stability and translatability. These two ERbeta SNPs have been investigated for association with disease in a large number of reports.

RESULTS

Here we examined allelic expression in breast tumor samples from heterozygous individuals. A significant difference in mRNA levels of the two alleles was observed for one of the SNPs. A cell model system was employed to further investigate potential molecular effects of the two SNPs. We used a modified plasmid, containing the ERbeta promoter and ERbeta 3'UTRs which include the different alleles of investigated SNPs. Quantitative Real-Time PCR was used to determine mRNA levels after inhibition of transcription by actinomycin D, and a luciferase assay was used to determine protein levels. The obtained results suggested that there was no difference in mRNA stability or translatability between the alleles of investigated SNPs.

CONCLUSION

Our results indicate that observed associations between ERbeta 3'UTR SNPs and disease susceptibility are due to linkage disequilibrium with another gene variant, rather than the variant itself being the susceptibility factor.

+331G/A variant in the progesterone receptor gene, postmenopausal hormone use and risk of breast cancer

A functional promoter polymorphism in the progesterone receptor (PR) gene previously has been associated with an increased risk of postmenopausal breast cancer. Whether the relationship between genetic variation in PR and risk of breast cancer is modified by postmenopausal hormone (PMH) use is unknown. Thus, we conducted a case-control study nested within the prospective Nurses' Health Study to evaluate if the risk of breast cancer associated with having the +331 A risk allele was modified by PMH use. Genotyping of this SNP was available for 1,664 postmenopausal breast cancer cases and 2,391 controls. Logistic regression was used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) for breast cancer. Women who were carriers of 1 or both variant A alleles had a 31% increased risk of developing breast cancer (95% CI 1.04-1.65). PMH use significantly modified the association between the +331G/A polymorphism and risk (p-interaction <0.05). Among never users of PMH, women who were variant carriers had a significantly increased risk of breast cancer compared to those with the wild-type genotype (OR = 2.57; 95% CI 1.64-4.02). The +331G/A polymorphism was not associated with breast cancer risk among past (OR = 1.23; 95% CI 0.77-1.97) or current (OR = 1.14; 95% CI 0.84-1.56) PMH users. The data from this large prospective study provide evidence for a 2-fold increased risk of developing postmenopausal breast cancer among never users of PMH with the +331G/A SNP. This finding adds to the evidence that the PR has an important etiologic role in breast cancer and should be evaluated in future studies.

Sex steroid metabolism polymorphisms and mammographic density in pre- and early perimenopausal women

Introduction

We examined the association between mammographic density and single-nucleotide polymorphisms (SNPs) in genes encoding CYP1A1, CYP1B1, aromatase, 17β-HSD, ESR1, and ESR2 in pre- and early perimenopausal white, African-American, Chinese, and Japanese women.

Methods

The Study of Women's Health Across the Nation is a longitudinal community-based cohort study. We analyzed data from 451 pre- and early perimenopausal participants of the ancillary SWAN Mammographic Density study for whom we had complete information regarding mammographic density, genotypes, and covariates. With multivariate linear regression, we examined the relation between percentage mammographic breast density (outcome) and each SNP (primary predictor), adjusting for age, race/ethnicity, parity, cigarette smoking, and body mass index (BMI).

Results

After multivariate adjustment, the CYP1B1 rs162555 CC genotype was associated with a 9.4% higher mammographic density than the TC/TT genotype (P = 0.04). The CYP19A1 rs936306 TT genotype was associated with 6.2% lower mammographic density than the TC/CC genotype (P = 0.02). The positive association between CYP1A1 rs2606345 and mammographic density was significantly stronger among participants with BMI greater than 30 kg/m² than among those with BMI less than 25 kg/m² (P_interaction = 0.05). Among white participants, the ESR1 rs2234693 CC genotype was associated with a 7.0% higher mammographic density than the CT/TT genotype (P = 0.01).

Conclusions

SNPs in certain genes encoding sex steroid metabolism enzymes and ESRs were associated with mammographic density. Because the encoded enzymes and ESR1 are expressed in breast tissue, these SNPs may influence breast cancer risk by altering mammographic density.

Estrogen receptor beta gene mutations in Indian infertile men

Recent studies suggest that estrogens play an important role in male fertility. Estrogen signaling is mediated by Estrogen Receptors (ERalpha and ERbeta). Association of ERbeta with male infertility has not been analyzed to date except for genotyping of known polymorphisms in two different studies, which yielded controversial interpretation. Hence, we performed sequencing of all the exons and untranslated regions of ERbeta gene in 300 infertile and 255 fertile control Indian men. We identified eight novel mutations and four known single nucleotide polymorphisms (SNPs). Of the eight novel mutations, four were non-synonymous, of which one was detected only in infertile men, whereas the other three mutations were detected only in fertile men. Using different bioinformatics tools, we predicted that non-synonymous mutations were benign and they neither altered the structure nor the function of the protein. Among synonymous novel mutations, one was detected in both fertile and infertile men, two were exclusive to infertile men and one was exclusive to fertile men. None of the known SNPs or novel mutations showed statistically significant difference between infertile and fertile men. Moreover, infertile men having ERbeta mutations had normal reproductive tract and serum hormone levels. Our results suggest that the SNPs and mutations in ERbeta gene are not a common cause of spermatogenesis failure in Indian men, although mutations specifically found in infertile men can affect transcription, translation or have synergic effect with other variants in causing infertility.

The protective association of high plasma enterolactone with breast cancer is reasonably robust in women with polymorphisms in the estrogen receptor alpha and beta genes

It is plausible that polymorphisms in the estrogen receptor alpha and beta genes (ESR1 and ESR2) may modulate the association between enterolactone and breast cancer. Seven polymorphisms in ESR1 (rs827422, rs1709184, rs2347867, rs3020328, rs72207, rs2982896, and rs2234693) and 5 polymorphisms in ESR2 (rs915057, rs1269056, rs1256033, rs3020450, and rs3020443) were selected. The risk of breast cancer for these polymorphisms was estimated among 542 cases and 1076 matched controls from the population-based Malmö Diet and Cancer cohort. The joint effect of these polymorphisms and enterolactone was estimated among those individuals about whom we had information on enterolactone blood concentration (365 cases and 728 controls). Breast cancer risk was not significantly associated with any of the selected polymorphisms. We found a tendency for an interaction between a polymorphism in intron 3 of ESR1 (rs2347867) and enterolactone concentration (P = 0.07). Breast cancer and enterolactone concentration were not associated among those homozygous for the major allele (A) (P = 0.93), whereas we found an inverse association among carriers of the minor allele (G) (P = 0.007). None of the other polymorphisms seem to modify the association between enterolactone and breast cancer. This study suggests that the protective association of enterolactone is reasonably robust across the investigated genotypes. The suggested interaction between enterolactone concentration and rs2347867 needs to be confirmed in larger samples.

Polymorphisms in the promoter region of ESR2 gene and breast cancer susceptibility

Genetic variations like single nucleotide polymorphisms (SNPs) in genes involved in estrogen biosynthesis, metabolism and signal transduction have been suggested to affect breast cancer susceptibility. In this study we tested the hypothesis that polymorphisms in the promoter of ESR2 gene may be associated with increased risk for breast cancer. We analyzed three SNPs in the promoter region of human ESR2 gene by means of allele-specific tetra-primer PCR. A total of 318 sporadic breast cancer cases and 318 age-matched controls were included in the study. With regard to homozygous genotypes, women with sporadic breast cancer more frequently carried the CC genotype of ESR2 promoter SNP rs2987983 (OR 1.99, p=0.005). Calculation of allele positivity demonstrated that presence of T allele of this SNP was more frequent in healthy women. Our data suggest that a SNP in the promoter region of ESR2 gene might be able to affect breast cancer risk. These results further support the emerging hypothesis that ERbeta is an important factor in breast cancer development.

Association of ESR1 gene tagging SNPs with breast cancer risk

We have conducted a three-stage, comprehensive single nucleotide polymorphism (SNP)-tagging association study of ESR1 gene variants (SNPs) in more than 55,000 breast cancer cases and controls from studies within the Breast Cancer Association Consortium (BCAC). No large risks or highly significant associations were revealed. SNP rs3020314, tagging a region of ESR1 intron 4, is associated with an increase in breast cancer susceptibility with a dominant mode of action in European populations. Carriers of the c-allele have an odds ratio (OR) of 1.05 [95% Confidence Intervals (CI) 1.02-1.09] relative to t-allele homozygotes, P = 0.004. There is significant heterogeneity between studies, P = 0.002. The increased risk appears largely confined to oestrogen receptor-positive tumour risk. The region tagged by SNP rs3020314 contains sequence that is more highly conserved across mammalian species than the rest of intron 4, and it may subtly alter the ratio of two mRNA splice forms.

The influence of genetic variation in 30 selected genes on the clinical characteristics of early onset breast cancer

Introduction

Common variants that alter breast cancer risk are being discovered. Here, we determine how these variants influence breast cancer prognosis, risk and tumour characteristics.

Methods

We selected 1,001 women with early onset nonfamilial invasive breast cancer from the Prospective study of Outcomes in Sporadic versus Hereditary breast cancer (POSH) cohort and genotyped 206 single nucleotide polymorphisms (SNPs) across 30 candidate genes. After quality control, 899 cases and 133 SNPs remained. Survival analyses were used to identify SNPs associated with prognosis and determine their interdependency with recognized prognostic factors. To identify SNPs that alter breast cancer risk, association tests were used to compare cases with controls from the Wellcome Trust Case Control Consortium. To search for SNPs affecting tumour biology, cases were stratified into subgroups according to oestrogen receptor (ER) status and grade and tested for association.

Results

We confirmed previous associations between increased breast cancer risk and SNPs in CASP8, TOX3 (previously known as TNRC9) and ESR1. Analysis of prognosis identified eight SNPs in six genes (MAP3K1, DAPK1, LSP1, MMP7, TOX3 and ESR1) and one region without genes on 8q24 that are associated with survival. For MMP7, TOX3 and MAP3K1 the effects on survival are independent of the main recognized clinical prognostic factors. The SNP in 8q24 is more weakly associated with independent effects on survival. Once grade and pathological nodal status (pN stage) were taken into account, SNPs in ESR1 and LSP1 showed no independent survival difference, whereas the effects of the DAPK1 SNP were removed when correcting for ER status. Interestingly, effects on survival for SNPs in ESR1 were most significant when only ER-positive tumours were examined. Stratifying POSH cases by tumour characteristics identified SNPs in FGFR2 and TOX3 associated with ER-positive disease and SNPs in ATM associated with ER-negative disease.

Conclusions

We have demonstrated that several SNPs are associated with survival. In some cases this appears to be due to an effect on tumour characteristics known to have a bearing on prognosis; in other cases the effect appears to be independent of these prognostic factors. These findings require validatation by further studies in similar patient groups.

Do Estrogen Receptor beta Polymorphisms Play A Role in the Pharmacogenetics of Estrogen Signaling?

Estrogen hormones play critical roles in the regulation of many tissue functions. The effects of estrogens are primarily mediated by the estrogen receptors (ER) alpha and beta. ERs are ligand-activated transcription factors that regulate a complex array of genomic events that orchestrate cellular growth, differentiation and death. Although many factors contribute to their etiology, estrogens are thought to be the primary agents for the development and/or progression of target tissue malignancies. Many of the current modalities for the treatment of estrogen target tissue malignancies are based on agents with diverse pharmacology that alter or prevent ER functions by acting as estrogen competitors. Although these compounds have been successfully used in clinical settings, the efficacy of treatment shows variability. An increasing body of evidence implicates ERalpha polymorphisms as one of the contributory factors for differential responses to estrogen competitors. This review aims to highlight the recent findings on polymorphisms of the lately identified ERbeta in order to provide a functional perspective with potential pharmacogenomic implications.