Estrogen Receptor Status In Breast Cancer Research Articles

Risk of estrogen receptor-specific breast cancer by family history of estrogen receptor subtypes and other cancers.

The extent to which the risk of estrogen receptor (ER)-specific breast cancer is associated with ER status of breast cancer and other cancers among first-degree relatives is unclear. This population-based cohort included 464 707 cancer-free women in Stockholm, Sweden, during 1978-2019. For ER-negative and ER-positive breast cancers, we estimated hazard ratios (HRs) associated with ER status of female first-degree relatives with breast cancer and of other cancers in all first-degree relatives. Associations between ER-negative and ER-positive status by family cancer history were estimated using logistic regression in a case-only design. Women with familial ER-positive breast cancer had 1.87 times (95% confidence interval [CI] = 1.77 to 1.97) higher risk of ER-positive subtype, whereas the corresponding hazard ratio for ER-negative was 2.54 (95% CI = 2.08 to 3.10) when having familial ER-negative breast cancer. The risk increased with an increasing number of female first-degree relatives having concordant subtypes and younger age at diagnosis (Ptrend <.001 for both). Nonbreast cancers among first-degree relatives were associated with both ER-positive (HR = 1.14, 95% CI = 1.10 to 1.17) and ER-negative (HR = 1.08, 95% CI = 1.01 to 1.16) breast cancers. Compared with women with ER-positive breast cancer, women with ER-negative breast cancer were more likely to have family history of liver (odds ratio [OR] = 1.33, 95% CI = 1.05 to 1.67), ovary (OR = 1.28, 95% CI = 1.01 to 1.61), and testicle cancer (OR = 1.79, 95% CI = 1.01 to 3.16) but less likely to have family history of endometrial cancer (OR = 0.77, 95% CI = 0.60 to 1.00) and leukemia (OR = 0.72, 95% CI = 0.56 to 0.91). Risk of ER-specific breast cancer differs according to ER status of female first-degree relatives with breast cancer and some other cancers of first-degree relatives. This family history information should be considered in the individual risk prediction for ER subtypes.

NOHA: A sensitive, low-cost, and accessible blood-based biomarker to determine breast cancer estrogen receptor status in low-resource settings.

580 Background: Significant challenges to breast cancer control in low- and middle-income countries (LMICs) include late-stage disease presentation because of few/no early detection programs, inadequately staffed and equipped pathology laboratories, and constrained treatment options. Estrogen receptor (ER) expression is critical to determining candidacy for cost efficient and accessible hormonal agents in LMICs; however, access to standard immunohistochemistry (IHC)-based ER analysis is grossly limited/nonexistent due to cost and technical requirements. We have identified Nw-hydroxy-L-Arginine (NOHA) as a low cost and accessible blood-based biomarker to distinguish estrogen-receptor negative (ER–) from estrogen-receptor positive (ER+) breast cancer, differentiate ER– high grade versus low grade tumors, and correlate ER– molecular phenotype with ethnic variation. Our studies with US patients suggest the NOHA threshold of &lt;4nM as a reliable indicator of ER– versus ER+ disease (Table 1). Here we examine the clinical utility of NOHA as an alternative to IHC in distinguishing ER– from ER+ breast tumors in Tanzanian patients. Methods: Following informed consent, 70 newly diagnosed breast cancer patients were recruited at Kilimanjaro Christian Medical Center (KCMC; Moshi, Tanzania). Prior to any treatment, a needle prick amount of blood was collected from each patient on a Noviplex plasma card (Shimadsu, U.S.) and stored at -80˚C. Plasma cards and unstained tumor pathology slides were shipped at 2-3 months intervals to US labs for NOHA and immunohistochemistry (IHC) ER testing. Statistical difference was set at p&lt;0.01, with NOHA and IHC assay operators blinded to patient clinical status. Results: Our early data show correlation between NOHA levels and ER IHC results, providing a means to distinguish ER– from ER+ breast cancer in the low-resource setting. Plasma cards stored at -80˚C for up to 3 months retained NOHA stability in assays involving a proprietary antibody-based ELISA, and by LC-MS. Conclusions: This study suggests the clinical utility of NOHA as a cost-effective, accessible replacement for standard IHC testing in determining ER status among breast cancer patients in LMICs, promising to extend access to cost efficient and available hormonal agents and improving outcomes and quality of life. The present study provides foundational knowledge for broader studies of NOHA utility in global breast cancer control, as well as in ongoing development of NOHA rapid-testing technologies. [Table: see text]

Risk of Breast, Prostate, and Colorectal Cancer Diagnoses Among HIV-Infected Individuals in the United States.

Although people living with HIV or AIDS (PLWHA) are at higher risk for many cancers, breast, prostate, and colorectal cancer rates are lower in this patient population. Because these tumors are often screen-detected, these inverse associations could be driven by HIV-related differences in utilization of cancer screening. We ascertained incident breast, prostate, and colorectal cancer in PLWHA using data from the HIV/AIDS Cancer Match Study (1996-2012). Comparisons with general population cancer rates were made using standardized incidence ratios (SIRs), overall and stratified by tumor stage/size, breast cancer estrogen receptor status, and colorectal site. We also examined the potential effect of study design and unmeasured confounding on inverse standardized incidence ratios. Compared with the general population, PLWHA had lower rates of invasive breast (SIR = 0.63, 95% confidence interval [CI] = 0.58 to 0.68), prostate (SIR = 0.48, 95% CI = 0.46 to 0.51), proximal colon (SIR = 0.67, 95% CI = 0.59 to 0.75), distal colon (SIR = 0.51, 95% CI = 0.43 to 0.59), and rectal cancers (SIR = 0.69, 95% CI = 0.61 to 0.77). Reduced risk persisted across tumor stage/size for prostate and colorectal cancers. Although distant-stage breast cancer rates were not reduced (SIR = 0.94, 95% CI = 0.73 to 1.20), HIV-infected women had lower rates of large (>5 cm) breast tumors (SIR = 0.65, 95% CI = 0.50 to 0.83). The magnitude of these inverse standardized incidence ratios could not plausibly be attributed to case underascertainment, out-migration, or unmeasured confounding. Breast, prostate, and colorectal cancer rates are markedly lower among PLWHA, including rates of distant-stage/large tumors that are not generally screen-detected. This set of inverse HIV-cancer associations is therefore unlikely to be due primarily to differential screening and may instead represent biological relationships requiring future investigation.

Breast Cancer Estrogen Receptor Status According to Biological Generation: US Black and White Women Born 1915-1979.

Evidence suggests that contemporary population distributions of estrogen-receptor (ER) status among breast cancer patients may be shaped by earlier major societal events, such as the 1965 abolition of legal racial discrimination in the United States (state and local "Jim Crow" laws) and the Great Famine in China (1959-1961). We analyzed changes in ER status in relation to Jim Crow birthplace among the 46,417 black and 339,830 white US-born, non-Hispanic women in the Surveillance, Epidemiology, and End Results (SEER) 13 Registry Group who were born between 1915 and 1979 and diagnosed (ages 25-84 years, inclusive) during 1992-2012. We grouped the cases according to birth cohort and quantified the rate of change using the haldane (which scales change in relation to biological generation). The percentage of ER-positive cases rose according to birth cohort (1915-1919 to 1975-1979) only among women diagnosed before age 55. Changes according to biological generation were greater among black women than among white women, and among black women, they were greatest among those born in Jim Crow (versus non-Jim Crow) states, with this group being the only group to exhibit high haldane values (>|0.3|, indicating high rate of change). Our study's analytical approach and findings underscore the need to consider history and societal context when analyzing ER status among breast cancer patients and racial/ethnic inequities in its distribution.

Abstract 540: Deep learning to determine breast cancer estrogen receptor status from nuclear morphometric features in H&amp;E images

Abstract We hypothesized that the spatial arrangement of nuclei in a hematoxylin and eosin (H&amp;E) stained image contains a vast quantity of latent information that is currently underutilized. We tested this hypothesis on the classification of breast cancer biopsies as estrogen receptor (ER) positive or negative. While determining ER status typically requires immunohistochemistry (IHC) staining, we aimed to recapitulate this step by predicting ER status directly from H&amp;E stained slides. By training a deep neural network on nuclear-morphometric features, we demonstrate the power of machine learning to provide insights about cancer biology, and aim to scale precision oncology for the developing world. We constructed a learning pipeline that segments nuclei from H&amp;E stained slides scanned into digital images, extracts shape and orientation descriptors, and uses a deep neural network to learn spatial features to predict ER status. After training the pipeline on 57 tissue cores of invasive ductal carcinoma (IDC), we were able to predict ER status in patients with IDC in a statistically significant manner (AUC=0.72, 95%CI=0.55-0.88, n=56) and ductal carcinoma in situ (AUC=0.82, 95%CI=0.74-0.89, n=106). To our knowledge, this is the first work to show that nuclear morphometric information can be used to predict the molecular status of a breast cancer tumor. An initial analysis of the features learned by the deep neural network provides a glimpse into the mechanistic differences between ER+ and ER- cancers: suggesting the importance of spatial heterogeneity in distinguishing between ER+ and ER-. We anticipate that further analysis will provide deeper insights about the morphological differences between ER+ and ER- cancers, and that this type of analysis can be applied to other markers and cancers. Moreover, an optimized version of this pipeline may serve patients in the developing world by providing a means to predict marker status directly from H&amp;E images. Citation Format: Rishi R. Rawat, Daniel Ruderman, David B. Agus, Paul Macklin. Deep learning to determine breast cancer estrogen receptor status from nuclear morphometric features in H&amp;E images [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 540. doi:10.1158/1538-7445.AM2017-540

Metrics for monitoring cancer inequities: residential segregation, the Index of Concentration at the Extremes (ICE), and breast cancer estrogen receptor status (USA, 1992-2012).

To address the paucity of evidence on residential segregation and cancer, we explored their relationship using a new metric: the Index of Concentration at the Extremes (ICE). We focused on breast cancer estrogen receptor (ER) status, a biomarker associated with survival and, etiologically, with social and economic privilege. We obtained data from the 13 registry group of US Surveillance, Epidemiology, and End Results (SEER) program for 1992-2012 on all women aged 25-84 who were diagnosed with primary invasive breast cancer (n=516,382). We appended to each case's record her annual county median household income quintile and the quintile for her annual county value for ICE measures for income (≤20th vs.≥80th household income quintile), race/ethnicity (black vs. white), and income plus race/ethnicity (low-income black vs. high-income white). The odds of being ER+ versus ER- were estimated in relation to the county-level income and ICE measures, adjusting for relevant covariates. Women in the most privileged versus deprived county quintile for household income and for all three ICE measures had a 1.1- to 1.3-fold increased odds (95% confidence intervals excluding 1) of having an ER+ tumor. These results were robust to adjustment for age at diagnosis, cancer registry, tumor characteristics (tumor stage, size, histology, grade), and race/ethnicity. A focus on segregation offers news possibilities for understanding how inequitable group relations contribute to cancer inequities. The utility of employing the ICE for monitoring cancer inequities should be investigated in relation to other cancer outcomes.

Automatic image analysis algorithm for quantitative assessment of breast cancer estrogen receptor status in immunocytochemistry

The paper presents an algorithm for quantification the degree of receptor expression to steroid hormones by automatic analysis of microscope images of immunocytochemical specimens. During experiments a high correlation between the results of the automatic analysis and visual expert assessment was shown and the possibility to apply the proposed algorithm to automate immunocytochemical analysis was confirmed.

Validation of EP1 antibody clone for estrogen receptor immunohistochemistry in breast cancer.

Estrogen receptor (ER) tumor's status is critical for breast cancer management. A new rabbit antibody clone, EP1, is now available for ER status determination. The objective was to validate the EP1 antibody clone for its use in breast cancer ER status determination in a clinical setting against the previous standard, SP1. EP1 clone was assessed in 130 consecutive cases, including 50 ER-negative (<1% ER expression), 13 ER-low-positive (1% to 9% ER expression), and 67 ER-positive (≥10% ER expression). Using EP1 versus SP1, positive agreement (sensibility) was 92.5% and negative agreement (specificity) was 100%, leading to an overall agreement of 95.4%. All discordant cases (n=6) were ER-low-positive. SP1 was remeasured in 13 ER-low-positive and in 11 ER-negative cases. Overall agreement between SP1 initial tumor status and reassessment was 70.8% in those negative and low-positive cases. In conclusion, EP1 antibody has been validated for use in breast cancer with a positive agreement ≥90% and a negative agreement ≥95%, as recommended. Also, overall agreement between EP1 and SP1 was as good as between the SP1 initial status and SP1 reassessment.

Combined Effects of Circulating Levels of 25-Hydroxyvitamin D and Th1 and Th2 Cytokines on Breast Cancer Estrogen Receptor Status

Vitamin D has been recognized for its immune-modulating properties. We have previously found that levels of 25OHD, and cytokines including IL5, IFNα2, and TNFα, are also associated with estrogen receptor (ER) negative breast cancer in younger women. Thus, we hypothesized that there may be interactions between vitamin D and the immune system in influencing breast cancer ER status, which was tested in 490 women with incident breast cancer. There was no correlation of the levels of 25OHD with any cytokine, and their associations with tumor ER negative status were independent of each other. However, premenopausal women with low 25OHD and high TNFα levels had the highest likelihood of having ER negative cancer (odds ratio [OR] = 7.32, 95% confidence interval [CI] = 2.44−21.98), with evidence of synergy between the two (relative excess risk due to interaction [RERI] = 5.46, p for additive interaction = 0.14, and p for multiplicative interaction = 0.09). There were similar synergistic associations between 25OHD and IL5, and several IFNα2 to Th2 cytokine ratios. This is the first study to provide evidence of interactions between vitamin D and the immune system in relation to breast cancer ER status, which may inform combinational use of vitamin D and anti-inflammatory drugs for cancer prevention and therapy.

Abstract P4-04-02: RNA-seq reveals functional lncRNAs associated with estrogen-receptor status in breast cancer

Abstract Background: Long non-coding RNAs (lncRNAs) are pervasively transcribed in the genome yet their role in human disease is not well understood. LncRNAs can have regulatory effects on coding mRNAs through a number of mechanisms, including repressing their sense-strand protein-coding partners. There is also emerging evidence that estrogen signaling affects the expression of a wide variety of non-coding functional RNA transcripts in addition to protein-coding transcripts. We performed an RNA-seq study to characterize changes in lncRNA expression and evaluate their association to estrogen receptor (ER) status and estrogen signaling. Methods: We sequenced transcriptomes of core biopsy RNA from 45 breast tumors obtained from neoadjuvant clinical trials BrUOG 211A/211B. RNA was derived from biopsy samples obtained before exposure to run-in monotherapy with either nab-paclitaxel, bevacizumab or trastuzumab. Paired-end sequencing was performed using amplified total RNA with 74bp read length, yielding genome-wide transcriptomic data. Transcriptomic abundance and differential expression were estimated assuming Poisson-distributed read-counts. Paired-end sequence data was aligned to a lncRNA database containing 14,572 unique lncRNAs. Changes in relative abundance of lncRNA transcripts were tested for association with estrogen receptor status using the Wilcoxon rank-sum test. Expression levels of the ER-associated lncRNAs were investigated in RNA-seq data from ER-positive MCF7 cells in response to treatment with E2 and tamoxifen (3hr, 12 hr and a non-treated control). ER-responsive binding sites on or near the ER-associated lncRNAs were investigated in a ChIP-seq study in MCF7 cells following estrogen treatment. MCF7 cell-line RNA-seq and ChIP-seq data were obtained from publicly available Short Read Archive (ERX030990 and SRX113365) at NCBI. Results: On average, in each patient 5000 lncRNAs were detectable. Expression of 22 lncRNAs were associated ER status (p&amp;lt;0.05) in breast tumors. 17 of the 22 ER-associated lncRNAs were detectable in ER-positive MCF7 breast cancer cells and were all responsive to E2 (estradiol) treatment. Interestingly, all 17 lncRNAs showed significant downregulation (&amp;gt; = 2 fold) upon tamoxifen treatment. To further evaluate the regulatory relationship between ER and the 22 lncRNAs, we identified the binding sites of ER in estrogen-treated MCF7 cells using ChIP-seq. We found that &amp;gt;50% of the ER-associated lncRNAs had ER binding site either overlapping or neighboring the lncRNA. Discussion: We have shown that lncRNA expression levels are associated with ER status in breast tumors. We have further established that they are estrogen-responsive with a majority being direct targets of ER using cell-line data. Further functional validation studies are ongoing. We are also exploring lncRNA-mRNA expression for coding partners of lncRNAs to identify coding/noncoding gene regulatory networks important in estrogen response. Understanding the regulatory effects of lncRNA expression opens up new opportunities for stratification and management of breast cancers. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-04-02.

Abstract 1075: Steroid receptor reprogramming of the chromatin landscape: crosstalk at the genomic level.

Abstract Crosstalk between the estrogen receptor (ER) and the glucocorticoid receptor (GR) plays an important role in controlling many cellular processes. Physiological interactions between ER and GR are not only important for the development of certain tissues, such as the uterus and bone, but also may play an important role in breast cancer. Recent studies have shown that the GR and ER status in breast cancer is a significant factor for determining the outcome of the disease. However, the mechanistic details defining the cellular interactions between ER and GR are poorly understood. Since the regulation of receptor binding to response elements controls the transcriptional output in response to hormones, it is logical to suspect that co-treatment of cells with corticosteroids and estradiol would have an effect on the genome-wide binding landscapes for GR and ER. Therefore, using chromatin immunoprecipitation followed by high-throughput sequencing we investigated the changes in genome-wide binding of ER and GR upon co-activation and revealed that there is global re-arrangement of steroid receptor binding. Furthermore, we unveiled a novel mechanism dictating the molecular interplay between ER and GR. Genome-wide sequencing of DnaseI hypersensitive sites upon induction of GR shows that GR facilitates selective access of ER to specific sites in the genome by maintaining an accessible configuration at these response elements. In addition, activation of ER can affect chromatin structure at novel GR binding sites, resulting in a new class of GR binding elements. Further studies show that at the sites where ER binding is facilitated by GR, binding to these newly accessible sites is not dependent on the direct binding of ER to its response element. Instead ER is brought to these sites through interactions with other factors, such as AP1. Overall, these studies define genome level interactions between ER and GR whereby the activation of multiple steroid receptors has a dramatic impact on controlling which regulatory elements are accessible to each receptor. The unveiling of this mechanism is important for understanding the molecular interplay between ER and GR in development and in cancer and may represent a general mechanism for crosstalk between receptors. Citation Format: Tina B. Miranda, Ty C. Voss, Myong-Hee Sung, Songjoon Baek, Sam John, Mary Hawkins, Lars Grontved, R. Louis Schiltz, Gordon L. Hager. Steroid receptor reprogramming of the chromatin landscape: crosstalk at the genomic level. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1075. doi:10.1158/1538-7445.AM2013-1075

Night work and breast cancer estrogen receptor status – results from the German GENICA study

The potential mechanisms that link night-shift work with breast cancer have been extensively discussed. Exposure to light at night (LAN) depletes melatonin that has oncostatic and anti-estrogenic properties and may lead to a modified expression of estrogen receptor (ER) α. Here, we explored the association between shift work and breast cancer in subgroups of patients with ER-positive and -negative tumors. GENICA (Gene-ENvironment Interaction and breast CAncer) is a population-based case-control study on breast cancer with detailed information on shift work from 857 breast cancer cases and 892 controls. ER status was assessed by immunohistochemical staining. Associations between night-shift work and ER-positive and -negative breast cancer were analyzed with conditional logistic regression models, adjusted for potential confounders. ER status was assessed for 827 cases and was positive in 653 and negative in 174 breast tumors. Overall, 49 cases and 54 controls were "ever employed" in shift work including night shifts for ≥ 1 year. In total, "ever shift work" and "ever night work" were not associated with an elevated risk of ER-positive or -negative breast tumors. Night work for ≥ 20 years was associated with a significantly elevated risk of ER-negative breast cancer [odds ratio (OR) 4.73, 95% confidence interval (95% CI) 1.22-18.36]. Our case-control study suggests that long-term night-shift work is associated with an increased risk of ER-negative breast cancers. Further studies on histological subtypes and the analysis of other potentially relevant factors are crucial for discovering putative mechanisms.

Maintenance of S-nitrosothiol homeostasis plays an important role in growth suppression of estrogen receptor-positive breast tumors

IntroductionProtein denitrosylation by thioredoxin reductase (TrxR) is key for maintaining S-nitrosothiol (SNO) homeostasis, although its role in tumor progression is unknown. Therefore, the present study aimed to assess the role of altered SNO homeostasis in breast cancer cells.MethodsThe impairment of SNO homeostasis in breast cancer cells was achieved with the highly specific TrxR inhibitor auranofin and/or exposure to S-nitroso-L-cysteine. S-nitrosylated proteins were detected using the biotin switch assay. Estrogen receptor (ER) alpha knockdown was achieved using RNA silencing technologies and subcellular localization of ERα was analyzed by confocal microscopy. The Oncomine database was explored for TrxR1 (TXNRD1) expression in breast tumors and TrxR1, ER and p53 expression was analyzed by immunohistochemistry in a panel of breast tumors.ResultsThe impairment of SNO homeostasis enhanced cell proliferation and survival of ER+ MCF-7 cells, but not of MDA-MB-231 (ER-, mut p53) or BT-474 (ER+, mut p53) cells. This enhanced cell growth and survival was associated with Akt, Erk1/2 phosphorylation, and augmented cyclin D1 expression and was abolished by the ER antagonist fulvestrant or the p53 specific inhibitor pifithrin-α. The specific silencing of ERα expression in MCF-7 cells also abrogated the growth effect of TrxR inhibition. Estrogenic deprivation in MCF-7 cells potentiated the pro-proliferative effect of impaired SNO homeostasis. Moreover, the subcellular distribution of ERα was altered, with a predominant nuclear localization associated with phosphorylation at Thr311 in those cells with impaired SNO homeostasis. The impairment of SNO homeostasis also expanded a cancer stem cell-like subpopulation in MCF-7 cells, as indicated by the increase of percentage of CD44+ cells and the augmented capability to form mammospheres in vitro. Notably, ER+ status in breast tumors was significantly associated with lower TXNDR1 mRNA expression and immunohistochemical studies confirmed this association, particularly when p53 abnormalities were absent.ConclusionThe ER status in breast cancer may dictate tumor response to different nitrosative environments. Impairment of SNO homeostasis confers survival advantages to ER+ breast tumors, and these molecular mechanisms may also participate in the development of resistance against hormonal therapies that arise in this type of mammary tumors.

Proteomic evaluation of pesticide‐resistant breast cancer cell lines

Considerable evidence links cumulative and sustained exposure to estrogens as a key promoter of breast tumor proliferation. Chemicals with estrogenic activity can bind to the estrogen receptor (ER) affecting signaling and estrogen‐responsive genes. Organochlorines are a class of chemical pesticides that act as xenoestrogens to disrupt normal endocrine function. Methoxychlor and Toxaphene are two organochlorine pesticides that have been widely used in California. This study investigates the response to these pesticides in an ER‐dependent manner by utilizing the breast cancer cell lines, MCF7 (ER+) and MDA‐MB‐231 (ER−), and a proteomic‐based approach to evaluate molecular pathway involvement. Cytotoxicity studies demonstrate that MCF7 cells are more sensitive to both pesticides supporting the premise that organochlorines may be acting as endocrine disruptors. Furthermore, pesticide‐resistant clones of MCF7 and MDA‐MB‐231 were established and compared to sensitive cells in proteomic experiments focused on the mitochondrial subproteome due to its role in cellular detoxification and apoptosis. We report here the elevated expression of a small subset of mitochondrial proteins in response to long‐term organochlorine exposure. These results provide a basis for understanding specific pesticide‐induced molecular mechanisms and their possible relationship to ER status in breast cancer.

The Cell of Breast Cancer Origin Affects Tumor Estrogen Receptor Status.

Abstract It has been known for some time that breast cancer phenotype is dependent upon the initiating oncogene. However, it has only recently been demonstrated that breast cancer phenotype, including tumor histopathology, gene expression profile, and metastatic potential, may also depend upon the cellular subtype from which a tumor arises. Breast tumor estrogen receptor (ER) status is a common prognostic factor, and approximately 70% of all breast tumors are ER+; that is, they expresse ER in ≥5% of tumor cells. However, it remains unknown which factors determine breast cancer ER status. It is possible that the cell of tumor origin plays a role in determining the ER status of the resulting tumor. Our lab has developed a method to somatically introduce oncogenes into a developmentally normal mouse mammary gland with temporal control using the modified avian retrovirus RCAS. We have generated transgenic mice that express the RCAS receptor TVA under mammary cell selective markers and demonstrated our ability to infect individual cells and induce mammary tumors. In this study we used an RCAS vector encoding polyoma virus middle T antigen (PyMT) to infect transgenic adult MMTV-tva or WAP-tva mice. The MMTV LTR is though to be active in several different mammary cell types including luminal epithelial, progenitor, and stem cells. WAP is primarily active in more highly differentiated mammary epithelial cells. Tumors induced by RCAS-PyMT differ in histopathology between the two lines. Those arising in MMTV-tva mice have a predominately solid morphology, while those arising in WAP-tva mice display a predominately papillary morphology. Interestingly, we found that the majority of tumors arising in MMTV-tva mice are ER+ (61%), while tumors arising in WAP-tva mice are predominately ER- (95%). Our data suggest that tumors induced by the same oncogene from distinct cellular subtypes in the mouse mammary epithelium can significantly vary in histopathology, and that tumor ER status can be dependent upon the cell of tumor origin. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2163.

Differential gene expression associated with estrogen receptor status of breast cancer identified by microarray meta-analysis.

Abstract Abstract #2041 Introduction: Estrogen receptor (ER) positive breast cancer can be prevented by Tamoxifen. Currently, there are no markers for breast cancer risk that discriminate between the risk of ER positive versus ER negative disease. To identify patients likely to benefit from endocrine chemoprevention, a robust marker predicting ER status is needed. Microarray technology has identified genomic classifiers for breast cancer prognosis and prediction. We therefore conducted a meta-analysis of microarray data to identify individual genes associated with ER status of breast cancer.&amp;#x2028; Methods: Publicly available microarray gene expression data sets were mined using Gene Expression Omnibus (GEO), Oncomine, ArrayExpress, and Stanford Microarray Database (SMD). Study inclusion criteria are no prior drug treatment, known ER status, and raw data files available for at least 50 arrays. All analyses were conducted using Bioconductor Project's (http://www.bioconductor.org) open-source software in R statistical programming language. Packages used include limma, ArrayQualityMetrics, MetaArray, and GOstats. Data sets were individually normalized using rma, and differential gene expression was based on ER status. Meta-analytic test statistic was computed, multiple test correction was performed, and genes above the threshold of |Zscore| = 19.5 were included in further analysis.&amp;#x2028; Results: The search identified 23 publicly available gene expression data sets of primary breast tumors with known ER status, ten of which met inclusion criteria. Four of the ten contained cDNA array data files from SMD and were combined since they contained redundant files. To minimize platform and methodology discrepancies, we chose to focus our analysis on the six data sets which utilized the Affymetrix U133A array. The six data sets each contain 99-245 arrays, and represent a total of 644 ER+ and 268 ER- breast tumors. Bioinformatic analysis of the 86 differentially expressed genes associated with ER status using the criteria described above was then performed. To enrich for gene expression changes in pre-neoplastic lesions, genes known to be involved in progression and metastasis were eliminated from further study. The remaining genes were searched in Oncomine for differential expression according to ER status, in PubMed for previous association with breast cancer, and with our unpublished data for Gene Ontology annotations associated with ER status in breast cancer. We further narrowed the resulting list of 22 to 15 (ESR1, TFF1, AGR2, SCUBE2, CYP21A2, PIP, DACH1, BCL2, PROM1, RARES1, TMSL8, SRD5A1, SLC39A6, SCGB2A2, and FOXA1) based on functional redundancy.&amp;#x2028; Conclusion: Over the next 4 months, this gene set (along with 5 house-keeping genes) will be tested for differential expression in samples that we have collected from the contralateral unaffected breasts of women with ER positive and ER negative breast cancer. These studies are likely to identify candidate genes that may serve as markers of ER-specific risk. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2041.

Race/ethnicity and breast cancer estrogen receptor status: impact of class, missing data, and modeling assumptions

To test whether reported associations between race/ethnicity and breast cancer estrogen receptor (ER) status are inflated due to missing ER data, lack of socioeconomic data, and use of the odds ratio (OR) rather than the prevalence ratio (PR). We geocoded and added census tract socioeconomic data to all cases of primary invasive breast cancer (n = 42,420) among women diagnosed between 1998 and 2002 in two California cancer registries (San Francisco Bay Area; Los Angeles County) and analyzed the data using log binomial regression. Adjusting for socioeconomic position and tumor characteristics, in models using the imputed data, reduced the PR for the black versus white excess risk of being ER--from 1.76 (95% CI: 1.66, 1.86; adjusted for age and catchment area) to 1.47 (95% CI: 1.38, 1.56). The latter parameter estimate was 16% greater (i.e., 1.56) in models excluding women with missing ER data, and was 43% greater when estimated using the OR (i.e., 1.82). Studies on race/ethnicity and ER status that fail to account for missing data and socioeconomic data and report the OR are likely to yield inflated estimates of racial/ethnic disparities in ER status.

Comparison of immunostaining for estrogen receptor in breast cancer using the rabbit monoclonal antibody SP1 or the mouse monoclonal antibody 6F-11

11562 Background: A high-quality assay to detect estrogen receptor (ER) expression is crucial as ER status guides many therapeutic decisions in breast cancer. Previously the rabbit monoclonal antibody (Ab) SP1 was shown to be more sensitive than the mouse monoclonal Ab 1D5. Results were similar in a comparison of mouse Abs 6F11 and 1D5. This study compares the ER status in breast cancer using SP1 on cases previously interpreted as negative with 6F11. Methods: All low grade (1 or 2), ER negative, invasive breast carcinomas, reviewed at the British Columbia Cancer Agency between 2002 and 2006 were reviewed. Cases that had been stained at the Vancouver site (VCC) with 6F11 were selected and those with available tissue blocks were re-stained with SP1. The patient’s oncologist was notified of any changes in ER status. Results: 123 cases of low grade, ER negative invasive breast tumors were initially selected. 49 of these cases had been stained at VCC with 6F11. Tissue blocks were available for 45/49 (92%) of cases. 5/45 cancers (11%) were grade 1 and 40/45 (89%) were grade 2. With SP1 the ER status changed from negative to positive in 3/45 (6.7%) of the cases. For 2 cases the ER status changed because current scoring criteria regard a test as positive even if only rare cells stain. Review of original 6F11 stained sections revealed these 2 cases would be scored as ER positive using the new criteria. The third case was a core biopsy with scant tumor and only focal staining. Review revealed the change in ER status was likely due to sampling difference in the deeper section. Conclusions: Of 45 previously 6F11 ER negative cases restained with SP1, the ER status changed in 2 because of revised more sensitive scoring criteria and in 1 because of a sampling difference between the original and subsequent sections. The rabbit monoclonal Ab SP1 appears to be as sensitive as the mouse monoclonal Ab 6F11 in detecting ER expression in breast cancer. This highlights the need for good quality ER testing with highly sensitive antibodies. Additional data for grade 3 cases will be presented. No significant financial relationships to disclose.

Estrogen Receptor Testing of Breast Cancer in Current Clinical Practice: What's the Question?

Estrogen Receptor Testing of Breast Cancer in Current Clinical Practice: What's the Question?

Dietary intake of selected fatty acids, cholesterol and carotenoids and estrogen receptor status in premenopausal breast cancer patients.

Although a wealth of research has focused on the influence of diet on breast cancer risk, the relationships between dietary factors and tumor characteristics of breast cancer, like estrogen receptor (ER) status, are not well characterized. In a case-case study, we evaluated self-reported dietary intake for five individual carotenoids, selected fatty acids, and cholesterol 1 year before diagnosis in 34 premenopausal breast cancer patients with ER-negative tumors and 86 premenopausal breast cancer patients with ER-positive tumors from The University of Texas M. D. Anderson Cancer Center. In multivariate logistic regression analysis adjusted for age, body mass index, and ethnicity, high intakes of linoleic acid were associated with more than a threefold greater risk of ER-negative disease than ER-positive disease (odds ratio (OR) = 3.48, 95% confidence interval (CI) = 1.42-8.54), whereas high cholesterol intake was associated with lower risk of ER-negative disease (OR = 0.35, 95% CI = 0.14-0.92). In a model evaluating carotenoids, selected fatty acids, and cholesterol together, the association with high intake of linoleic acid remained statistically significant (OR = 3.96,95% CI = 1.53-10.25), while those for high intake of cholesterol (OR = 0.38, 95% CI = 0.14-1.03) and low intake of cryptoxanthin (OR = 0.43, 95% CI = 0.17-1.06) were of marginal significance. While no striking associations were observed for the intakes of total carotenoids, selected fatty acids, and cholesterol, our analysis revealed an association for the consumption of a specific fatty acid (i.e., linoleic acid), suggesting dietary influence of this factor on ER status in premenopausal breast cancer patients. However, larger studies are needed to clarify the role of micronutrients in ER status in breast cancer.