Estrogen and progesterone receptor determinations in breast cancer. Technology, biology and clinical significance

Vascular Endothelial Growth Factor Expression by Immunohistochemistry as a Possible Indicator of Prognosis in Invasive Breast Carcinoma of No Special Type

Context

Angiogenesis, the formation of new blood vessels from preexisting vascular network, is essential for tumor growth and spread. Vascular endothelial growth factor (VEGF) is a potent angiogenic growth factor.

Aims

To assess the expression of VEGF in invasive carcinoma of no special type and its correlation with all the known prognostic factors of breast carcinoma.

Settings and Design

Descriptive.

Materials and Methods

Mastectomy specimens were studied noting the clinical details. The formalin-fixed tissues were subjected to routine processing and hematoxylin and eosin sections and studied extensively for all the histological prognostic factors. Representative sections from each case with the tumor were subjected to immunohistochemistry (IHC) staining with VEGF, estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2/neu) antibodies.

Statistical Analysis Used

Descriptive statistics, Chi-square tests, contingency table analysis using SPSS for Windows.

Results

One hundred and twelve cases of invasive carcinoma of special type were studied to evaluate various clinicopathological parameters. The association of VEGF with clinicopathological parameters and all the known prognostic factors was studied to note its significance. VEGF overexpression was observed in 69% of the cases. It was noted that larger tumor size, higher histological grade, lymphovascular invasion, nodal involvement, tumor necrosis, high microvessel density, ER negativity, PR negativity, and HER2/neu positivity had a significant statistical association with VEGF overexpression.

Conclusions

We conclude that incorporating VEGF as a biomarker along with the known factors into a prognostic index will not only help predict clinical outcome more accurately, but also determines the patient who can be benefited with combinational therapy including anti-VEGF factors.

Effects of doxorubicin associated with amniotic membrane stem cells in the treatment of canine inflammatory breast carcinoma (IPC-366) cells

BACKGROUND

Tumours in mammary glands represent the most common neoplasia in bitches, as in humans. This high incidence results in part from the stimulation of sex hormones on these glands. Among mammary tumours, inflammatory carcinoma is the most aggressive, presenting a poor prognosis to surgical treatment and chemotherapy. One of the most widely used chemotherapy drugs for breast cancer treatment is doxorubicin (DOXO). Alternative therapies have been introduced in order to assist in these treatments; studies on treatments using stem cells have emerged, since they have anti-inflammatory and immunomodulatory properties. The aim of this study was to evaluate the effects of DOXO and canine amniotic membrane stem cells (AMCs) on the triple-negative canine inflammatory mammary carcinoma cell line IPC-366.

METHODS

Four experimental groups were analysed: a control group without treatment; Group I with DOXO, Group II with AMC and Group III with an association of DOXO and AMCs. We performed the MTT assay with DOXO in order to select the best concentration for the experiments. The growth curve was performed with all groups (I-III) in order to verify the potential of treatments to reduce the growth of IPC-366. For the cell cycle, all groups (I-III) were tested using propidium iodide. While in the flow cytometry, antibodies to progesterone receptor (PR), estrogen receptor (ER), PCNA, VEGF, IL-10 and TGF-β1 were used. For steroidogenic pathway hormones, an ELISA assay was performed.

RESULTS

The results showed that cells treated with 10 µg/mL DOXO showed a 71.64% reduction in cellular growth after 72 h of treatment. Reductions in the expression of VEGF and PCNA-3 were observed by flow cytometry in all treatments when compared to the control. The intracellular levels of ERs were also significantly increased in Group III (4.67% vs. 27.1%). Regarding to the levels of steroid hormones, significant increases in the levels of estradiol (E2) and estrone sulphate (S04E1) were observed in Groups I and III. On the other hand, Group II did not show differences in steroid hormone levels in relation to the control. We conclude that the association of DOXO with AMCs (Group III) promoted a reduction in cell growth and in the expression of proteins related to proliferation and angiogenesis in IPC-366 triple-negative cells.

CONCLUSIONS

This treatment promoted ER positive expression, suggesting that the accumulated oestrogen conducted these cells to a synergistic state, rendering these tumour cells responsive to ERs and susceptible to new hormonal cancer therapies.

Retrospective analysis of estrogen receptor 1 and N‑acetyltransferase gene expression in normal breast tissue, primary breast tumors, and established breast cancer cell lines

The expression levels of estrogen receptor 1 (ESR1), arylamine N‑acetyltransferase 1 (NAT1), and arylamine N‑acetyltransferase 2 (NAT2) are implicated in breast cancer; however, their co-expression profiles in normal breast tissue, primary breast tumors and established breast cancer cell lines are undefined. NAT1 expression is widely reported to be associated with ESR1 expression and is frequently investigated in breast cancer etiology. Furthermore, the NAT2 phenotype has been reported to modify breast cancer risk in molecular epidemiological association studies. Understanding the relationships between the expression levels of these genes is essential to understand their role in breast cancer etiology and treatment. In the present study, NAT1, NAT2 and ESR1 expression data were accessed from repositories of RNA‑Seq data covering 57 breast cancer cell lines, 1,043 primary breast tumors and 99 normal breast tissues. The relationships between gene expression, and between NAT1 activity and RNA expression in breast cancer cell lines were evaluated using non-parametric statistical analyses. Differences in gene expression in each dataset, as well as gene expression differences in normal breast tissue compared to primary breast tumors, and stratification by estrogen receptor status were determined. NAT1 and NAT2 mRNA expression were detected in normal and primary breast tumor tissues; NAT1 expression was much higher than NAT2. NAT1 and ESR1 expression were strongly associated, whereas NAT2 and ESR1 expression were not. Although NAT1 and NAT2 expression were associated, the magnitude was moderate. NAT1, NAT2, and ESR1 expression were increased in primary breast tumor tissue compared with normal breast tissue; however, the magnitude and significance of the differences were lower for NAT2. Analysis of NAT1, NAT2, and ESR1 expression in normal and primary breast tissues and breast cancer cell lines suggested that NAT1 and NAT2 expression are regulated by distinctive mechanisms, whereas NAT1 and ESR1 expression may have overlapping regulation. Defining these relationships is important for future investigations into breast cancer prevention.

Impact of Steroid Receptors, pS2 and Cathepsin D on the Outcome of N+ Postmenopausal Breast Cancer Patients Treated with Tamoxifen

In spite of the complexity of the biological basis of the hormonal regulation of breast cancer, clinical studies tend to simplify the information by mainly categorizing continuous variables related to hormonal status and not considering the interactions between variables. The present study was planned to examine the presence of an interaction between cathepsin D (Cath-D) and pS2 in patients treated with adjuvant tamoxifen in a homogeneous subset of node-positive postmenopausal patients and to evaluate the contribution of the interaction to the predictive ability of the model. Steroid receptors (ER and PgR) were measured in cytosol using the dextran-coated charcoal method, while Cath-D and pS2 were determined using commercially available immunoradiometric assays. The prognostic role of each variable and their joint effect were investigated using a Cox regression model. Biological variables were analyzed as continuous and when their prognostic relationship did not seem linear, a restricted cubic spline regression smoothing approach was adopted. The logarithm of hazard showed a linear relationship with the log(ER), while it i) remained almost constant up to about 20 fmol/mg and subsequently decreased for PgR; ii) was almost constant up to about 50 pmol/mg and subsequently decreased for Cath-D; iii) decreased for increasing log(value) up to about 33 ng/mg and subsquently increased for pS2. In the multivariate analysis both PgR and the interaction between pS2 and Cath-D retained a significant prognostic role. For low values of pS2, the prognosis worsened with the increase in Cath-D levels and this relationship reversed for high values of pS2. From the results of the present study we can conclude that i) a significant interaction between Cath-D and pS2 was found in this case series; ii) the prognostic relationships should not be underestimated in clinical decision making; iii) a predictive score obtained considering the contribution of PgR, pS2 and Cath-D could be useful for clinical use.

Mammary stem cells and parity-induced breast cancer protection- new insights

Parity (childbearing) significantly decreases a woman's risk of breast cancer and the protective effect is greater if the woman is younger and has more children. The mechanism/s of parity-induced protection are not known. Although several factors are postulated to play a role, we discuss how a reduction in the number of mammary stem cells (MaSCs) may lead to a reduction in breast cancer risk in parous women. Firstly we review the epidemiology linking childbearing to reduced breast cancer risk and discuss how additional births, a young age at first full term birth, and breastfeeding impact the protection. We then detail the mouse and human studies implicating MaSC in parity induced protection and the in-vivo work being performed in mice to directly investigate the effect of parity on MaSC. Finally we discuss the transplant and lineage tracing experiments assessing MaSC activity according to parity and the need to define if MaSC are indeed more carcinogen sensitive than mature mammary epithelial cells. Continuing and future studies attempting to define the parity induced mechanisms will aid in the development of preventative therapies.

Risk of Premenopausal and Postmenopausal Breast Cancer among Multiple Sclerosis Patients

Objective

To investigate risk of premenopausal and postmenopausal breast cancer among Multiple Sclerosis (MS) patients, considering tumor stage.

Methods

The Swedish Patient Register identified 19,330 women with MS between 1968 and 2012, matched individually with a cohort of 193,458 without MS. Matching variables were year of birth, sex, region of residence and vital status at the time of diagnosis. The cancer register identified 471 and 5,753 breast cancer cases among the MS and non-MS cohorts, respectively. Cox proportional hazard models estimated hazard ratios (HR) and 95% confidence intervals (CI) for premenopausal and postmenopausal breast cancer.

Results

Overall risk of postmenopausal breast cancer was 13% higher among MS patients compared with women without MS (HR = 1.13, 95% CI 1.02–1.26). Stratified analyses showed that the risk was statistically significantly increased in women diagnosed between 1968 and 1980 and those who were diagnosed at age 65 or older age. We observed a non-statistically significant risk only for stage 0–1 postmenopausal breast cancer (HR = 1.17, 95% CI 0.93–1.48). MS was not associated with premenopausal breast cancer.

Conclusion

The modest increased risk of postmenopausal breast cancer in women with MS may be due to surveillance bias, where contact with health services for one disease increases the risk of a second diagnosis being recorded.

The role of oestrogen and progesterone receptors in breast cancer - immunohistochemical evaluation of oestrogen and progesterone receptor expression in invasive breast cancer in women

Aim of the study

Expression of oestrogen and progesterone receptors is a very powerful and useful predictor. Because the response rate to hormonal treatment in breast cancer is associated with the presence of oestrogen and progesterone receptors, assessment of the receptor expression profile allows for prediction of breast cancer response to hormonal treatment. The aim of this study was to assess whether the expression of receptors for oestrogen (ER) and progesterone (PR) in the tumour tissue of patients with invasive breast cancer correlated with tumour histological type, histological grade of malignancy, tumour size, and lymph node status.

Material and methods

Materials consisted of histological preparations derived from patients treated for invasive breast cancer. Evaluations were conducted with histopathological and immunohistochemical methods using suitable antibodies.

Results

Among 231 cases of breast cancer 18 invasive lobular carcinomas (ILC) and 213 invasive ductal carcinomas (IDC) were diagnosed. Taking the histological type of tumour into account, oestrogen receptor-positive reaction was observed in 74.2% of IDC and 77.8% of ILC, and the positive response to PR was observed in 67.1% of IDC and 61.1% of ILC. Considering the histological grade, ER- in the largest percentage (72%) was observed in second-grade (G2) invasive carcinomas. Similarly, PR expression (75%) was found in the largest percentage in second-grade (G2) carcinomas. Based on our own studies and data from literature, it appears that the ER (+) status is an indicator of good prognosis, because it points to a less aggressive cancer, in which overall survival and disease-free time is longer in comparison with ER (–) tumours.

Conclusions

Determination of ER status may, therefore, have significant clinical value and is widely used in routine pathological diagnostics.

A systematic analysis of miRNA-mRNA paired variations reveals widespread miRNA misregulation in breast cancer

MicroRNAs (miRNAs) are a class of small noncoding RNAs that can regulate gene expression by binding to target mRNAs and induce translation repression or RNA degradation. There have been many studies indicating that both miRNAs and mRNAs display aberrant expression in breast cancer. Previously, most researches into the molecular mechanism of breast cancer examined miRNA expression patterns and mRNA expression patterns separately. In this study, we systematically analysed miRNA-mRNA paired variations (MMPVs), which are miRNA-mRNA pairs whose pattern of regulation can vary in association with biopathological features, such as the oestrogen receptor (ER), TP53 and human epidermal growth factor receptor 2 (HER2) genes, survival time, and breast cancer subtypes. We demonstrated that the existence of MMPVs is general and widespread but that there is a general unbalance in the distribution of MMPVs among the different biopathological features. Furthermore, based on studying MMPVs that are related to multiple biopathological features, we propose a potential crosstalk mechanism between ER and HER2.

Role of calcium sensing receptor (CaSR) in tumorigenesis

The extracellular Ca(2+)-sensing receptor (CaSR) is a robust promoter of differentiation in colonic epithelial cells and functions as a tumor suppressor in colon cancer. CaSR mediates its biologic effects through diverse mechanisms. Loss of CaSR expression activates a myriad of stem cell-like molecular features that drive and sustain the malignant and drug-resistant phenotypes of colon cancer. This CaSR-null phenotype, however, is not irreversible and induction of CaSR expression in CaSR-null cells promotes cell death mechanisms and restores drug sensitivity. The CaSR also functions as a tumor suppressor in breast cancer and promotes cellular sensitivity to cytotoxic drugs. BRCA1 and CaSR functions intersect in breast cancer cells, and CaSR activation can rescue breast cancer cells from the deleterious effect of BRCA1 mutations.

In silico discovery of mitosis regulation networks associated with early distant metastases in estrogen receptor positive breast cancers

The aim of this study was to perform comparative analysis of multiple public datasets of gene expression in order to identify common genes as potential prognostic biomarkers. Additionally, the study sought to identify biological processes and pathways that are most significantly associated with early distant metastases (<5 years) in women with estrogen receptor-positive (ER+) breast tumors. Datasets from three published studies were selected for in silico analysis of gene expression profiles of ER+ breast cancer, using time to distant metastasis as the clinical endpoint. A subset of 44 differently expressed genes (DEGs) was found common to all three studies and characterized by mitotic checkpoint genes and pathways that regulate mitotic spindle and chromosome dynamics. DEG promoter regions were enriched with NFY binding sites. Analysis of miRNA target sites identified significant enrichment of miR-192, miR-193B, and miR-16-1 targets. Aberrant mitotic regulation could drive increased genomic instability leading to a progression towards an early onset metastatic phenotype. The relative importance of mitotic instability may reflect the clinical utility of mitotic poisons in metastatic breast cancer, including poisons such as the taxanes, epothilones, and vinca alkaloids.

Placental weight and mortality in premenopausal breast cancer by tumor characteristics

Placental weight may be regarded as an indirect marker of hormone exposures during pregnancy. There is epidemiological evidence that breast cancer mortality in premenopausal women increases with placental weight in the most recent pregnancy. We investigated if this association differs by tumor characteristics, including expression of estrogen and progesterone receptors. In a Swedish population-based cohort, we followed 1,067 women with premenopausal breast cancer diagnosed from 1992 to 2006. Using Cox regression models, we estimated hazard ratios for the association between placental weight and risk of premenopausal breast cancer mortality. In stratified analyses, we estimated mortality risks in subjects with different tumor stages, estrogen receptor (ER) or progesterone receptor (PR) status. Compared with women with placental weight less than 600 g, women with a placental weight between 600 and 699 g were at a 50 % increased risk of mortality, however, not significant change in risk was observed for women with placental weight ≥ 700 g. Mortality risks associated with higher placental weight were more pronounced among ER(-) and PR(-) breast cancer tumors, where both a placental weight 600-699 g and ≥ 700 g were associated with a more than doubled mortality risks compared with tumors among women with placental weight less than 600 g. Moreover, stratified analyses for joint receptor status revealed that a consistent increased mortality risk by placental weight was only apparent in women with ER(-)/PR(-) breast cancer. The increased mortality risk in premenopausal breast cancer associated with higher placental weight was most pronounced among ER(-) and PR(-) tumors.

Long-term biomonitoring of breast cancer patients under adjuvant chemotherapy: the comet assay as a possible predictive factor

Most chemotherapy treatments induce DNA damage in the exposed patients. Using the comet assay and peripheral blood mononuclear cells (PBMC), we have quantified this induced DNA damage and studied its relationship with GSTM1 and GSTT1 polymorphisms, and clinical parameters. For this purpose, 29 Caucasian women, breast cancer patients under CMF or CEF adjuvant chemotherapy were included in the study. The clinical parameters considered were (i) therapies side effects, like haematological and biochemical toxicities, (ii) prognostic and predictive factors, like hormonal receptor expression, tumour differentiation degree, sickness stage, and nodal status, and (iii) the effectiveness of the chemotherapy measured as five years relapse probability. The results were also related to the confounding factor age. Comet assay results indicate that 13 patients were characterised by absence of induced DNA strand breaks, and 16 patients presented induced DNA strand breaks along the treatment. Relationships between comet variables and clinical parameters, found with principal component analysis, correlations, one-way ANOVA and multivariate logistic regression analyses revealed that: (1) baseline levels of DNA damage are related to GSTM1 genotype and to hormonal receptor expression; (2) GSTM1 genotype also influences comet results after chemotherapy, as it does the AST level; (3) the tail moment values of the cycle 6.1 and the sickness stage might predict cancer relapse at five years: for the Stage, OR = 13.8 (IIB versus I+IIA), 95% CI 0.80-238.97, and for 6.1 cycle TM, OR = 1.3, 95%, CI 0.97-1.79, with a potential model (10* Stage (I-IIA = 0, IIB = 1) + 6.1 cycle), that has a good predictive capacity, with an area under ROC curve of 0.872 (CI 0.62-1.00). To our knowledge, this is the first time such a predictive value is found for the comet assay. Nevertheless, before the comet assay could be used as a tool for oncologists, this relationship should be confirmed in more patients, and problems of standardisation and data interpretation should be solved.

Multiplex immunoassays of peptide hormones extracted from formalin-fixed, paraffin-embedded tissue accurately subclassify pituitary adenomas

BACKGROUND

The current gold standard for diagnostic classification of many solid-tissue neoplasms is immunohistochemistry (IHC) performed on formalin-fixed, paraffin-embedded (FFPE) tissue. Although IHC is commonly used, there remain important issues related to preanalytic variability, nonstandard methods, and operator bias that may contribute to clinically significant error. To increase the quantitative accuracy and reliability of FFPE tissue-based diagnosis, we sought to develop a clinical proteomic method to characterize protein expression in pathologic tissue samples rapidly and quantitatively.

METHODS

We subclassified FFPE tissue from 136 clinical pituitary adenoma samples according to hormone translation with IHC and then extracted tissue proteins and quantified pituitary hormones with multiplex bead-based immunoassays. Hormone concentrations were normalized and compared across diagnostic groups. We developed a quantitative classification scheme for pituitary adenomas on archived samples and validated it on prospectively collected clinical samples.

RESULTS

The most abundant relative hormone concentrations differentiated sensitively and specifically between IHC-classified hormone-expressing adenoma types, correctly predicting IHC-positive diagnoses in 85% of cases overall, with discrepancies found only in cases of clinically nonfunctioning adenomas. Several adenomas with clinically relevant hormone-expressing phenotypes were identified with this assay yet called "null" by IHC, suggesting that multiplex immunoassays may be more sensitive than IHC for detecting clinically meaningful protein expression.

CONCLUSIONS

Multiplex immunoassays performed on FFPE tissue extracts can provide diagnostically relevant information and may exceed the performance of IHC in classifying some pituitary neoplasms. This technique is simple, largely amenable to automation, and likely applicable to other diagnostic problems in molecular pathology.

Tissue proteomics of the human mammary gland: towards an abridged definition of the molecular phenotypes underlying epithelial normalcy

Our limited understanding of the biological impact of the whole spectrum of early breast lesions together with a lack of accurate molecular-based risk criteria for the diagnosis and assignment of prognostic significance to biopsy findings presents an important problem in the clinical management of patients harboring precancerous breast lesions. As a result, there is a need to identify biomarkers that can better determine the outcome of early breast lesions by identifying subpopulations of cells in breast premalignant disease that are at high-risk of progression to invasive disease. A first step towards achieving this goal will be to define the molecular phenotypes of the various cell types and precursors - generated by the stem cell hierarchy - that are present in normal and benign conditions of the breast. To date there have been very few systematic proteomic studies aimed at characterizing the phenotypes of the different cell subpopulations present in normal human mammary tissue, partly due to the formidable heterogeneity of mammary tissue, but also due to limitations of the current proteomic technologies. Work in our laboratories has attempted to address in a systematic fashion some of these limitations and here we present our efforts to search for biomarkers using normal fresh tissue from non-neoplastic breast samples. From the data generated by the 2D gel-based proteomic profiling we were able to compile a protein database of normal human breast epithelial tissue that was used to support the biomarker discovery program. We review and present new data on the putative cell-progenitor marker cytokeratin 15 (CK15), and describe a novel marker, dihydropyriminidase-related protein 3 (DRP3) that in combination with CK15 and other well known proteins were used to define molecular phenotypes of normal human breast epithelial cells and their progenitors in resting acini, lactating alveoli, and large collecting ducts of the nipple. Preliminary results are also presented concerning DRP3 positive usual ductal hyperplasias (UDHs) and on single cell layer columnar cells (CCCs). At least two bona fide biomarkers of undifferentiated ERα/PgR negative luminal cells emerged from these studies, CK15 and c-KIT, which in combination with transformation markers may lead to the establishment of a protein signature able to identify breast precancerous at risk of progressing to invasive disease.

Are estrogen receptor-positive breast cancers in BRCA1 mutation carriers sporadic?

There is a strong association between BRCA1 mutation carrier status and estrogen receptor-negative breast cancer. This has led to the idea that estrogen receptor-positive breast cancers in BRCA1 mutation carriers may be incidental or sporadic in nature and not as a direct result of BRCA1 dysfunction. A recent paper in Breast Cancer Research challenges this view.

Gene network signaling in hormone responsiveness modifies apoptosis and autophagy in breast cancer cells

Resistance to endocrine therapies, whether de novo or acquired, remains a major limitation in the ability to cure many tumors that express detectable levels of the estrogen receptor alpha protein (ER). While several resistance phenotypes have been described, endocrine unresponsiveness in the context of therapy-induced tumor growth appears to be the most prevalent. The signaling that regulates endocrine resistant phenotypes is poorly understood but it involves a complex signaling network with a topology that includes redundant and degenerative features. To be relevant to clinical outcomes, the most pertinent features of this network are those that ultimately affect the endocrine-regulated components of the cell fate and cell proliferation machineries. We show that autophagy, as supported by the endocrine regulation of monodansylcadaverine staining, increased LC3 cleavage, and reduced expression of p62/SQSTM1, plays an important role in breast cancer cells responding to endocrine therapy. We further show that the cell fate machinery includes both apoptotic and autophagic functions that are potentially regulated through integrated signaling that flows through key members of the BCL2 gene family and beclin-1 (BECN1). This signaling links cellular functions in mitochondria and endoplasmic reticulum, the latter as a consequence of induction of the unfolded protein response. We have taken a seed-gene approach to begin extracting critical nodes and edges that represent central signaling events in the endocrine regulation of apoptosis and autophagy. Three seed nodes were identified from global gene or protein expression analyses and supported by subsequent functional studies that established their abilities to affect cell fate. The seed nodes of nuclear factor kappa B (NFkappaB), interferon regulatory factor-1 (IRF1), and X-box binding protein-1 (XBP1)are linked by directional edges that support signal flow through a preliminary network that is grown to include key regulators of their individual function: NEMO/IKKgamma, nucleophosmin and ER respectively. Signaling proceeds through BCL2 gene family members and BECN1 ultimately to regulate cell fate.

Endocrine therapy for breast cancer: an overview

Endocrine therapy for breast cancer has been established in the adjuvant treatment for primary disease and in the treatment of advanced disease. The ER remains the best predictor of response although other factors exist and need to be identified. Pharmacological manipulation has been replacing ablative procedures. Tamoxifen used to be the most popular agent of choice and promising new agents include the pure anti-oestrogens and the third generation selective aromatase inhibitors. Ongoing and future studies will optimise treatment in established areas and will exploit its potential roles in preoperative use and chemoprevention.

Progesterone receptor status provides predictive value for adjuvant endocrine therapy in older estrogen receptor-positive breast cancer patients

Estrogen receptor (ER) status can predict the efficacy of endocrine therapy. However, the predictive significance of the progesterone receptor (PgR) is controversial in an adjuvant setting. Records of 758 ER+ breast cancer patients who received adjuvant tamoxifen (TAM) for 3-5 years were reviewed to evaluate the predictive value of PgR for TAM treatment in ER+/PgR+ and ER+/PgR- groups. By a median of 40 months' follow-up, there was no significant difference between the two groups with regard to disease-free-survival (DFS). On the basis of STEPP analysis showing the tendency of age effect on DFS in both the ER+/PgR- and ER+/PgR+ groups, we classified the ER+ patients into three strata by age (<45, 45-60, and >or=60 years). There was no significant difference in DFS and overall survival (OS) between the two groups in the <45 stratum and the 45-60 stratum. In contrast, the ER+/PgR- group had a worse prognosis in the >or=60 stratum with regard to both DFS (P=0.0484) and OS (P=0.0009). The results suggest that PgR status might be a predictive factor of benefit to be gained from adjuvant TAM for older ER+ patients with regard to DFS and OS. This should take into account older ER+/PgR- patients who tend to be resistant to TAM.

Association of physical activity with hormone receptor status: the Shanghai Breast Cancer Study

Evidence exists that breast tumors differing by estrogen receptor (ER) and progesterone receptor (PR) status may be phenotypically distinct diseases resulting from dissimilar etiologic processes. Few studies have attempted to examine the association of physical activity with breast cancer subtype. Such research may prove instructive into the biological mechanisms of activity. Consequently, this investigation was designed to assess the relationship between physical activity and hormone receptor-defined breast cancers in a population of Asian women in which the distribution of receptor types differed from traditional Western populations. Participants, ages 25 to 64 years, were recruited into this population-based, case-control study of breast cancer conducted in Shanghai, China from August 1996 to March 1998. Histologically confirmed breast cancer cases with available receptor status information (n = 1001) and age frequency-matched controls (n = 1,556) completed in-person interviews. Polytomous logistic regression was used to model the association between measures of activity with each breast cancer subtype (ER+/PR+, ER-/PR-, ER+/PR-, and ER-/PR+) using the control population as the reference group. Exercise in both adolescence and the last 10 years was associated with a decreased risk of both receptor-positive (ER+/PR+) and receptor-negative (ER-/PR-) breast cancers in both premenopausal and postmenopausal women (odds ratios, 0.44 and 0.51 and 0.43 and 0.21, respectively). Sweating during exercise within the last 10 years was also associated with decreased risk for receptor-positive and receptor-negative breast cancers among postmenopausal women (odds ratios, 0.58 and 0.28, respectively). These findings suggest that physical activity may reduce breast cancer risk through both hormonal and nonhormonal pathways.

Alcohol and postmenopausal breast cancer risk defined by estrogen and progesterone receptor status: a prospective cohort study

BACKGROUND

Alcohol intake has been reported to be positively associated with an increased risk of postmenopausal breast cancer; however, the association with the estrogen receptor (ER) and progesterone receptor (PR) status of the breast tumors remains unclear.

METHODS

Self-reported data on alcohol consumption were collected in 1987 and 1997 from 51,847 postmenopausal women in the population-based Swedish Mammography Cohort. Through June 30, 2004, 1188 invasive breast cancer case patients with known ER and PR status were identified during an average 8.3-year follow-up. We used Cox proportional hazards models to estimate multivariable relative risks (RRs) of breast cancer, adjusting for age; family history of breast cancer; body mass index; height; parity; age at menarche, first birth, and menopause; education level; use of postmenopausal hormones; and diet. Heterogeneity among groups was evaluated using the Wald test. All statistical tests were two-sided.

RESULTS

Alcohol consumption was associated with an increased risk for the development of ER-positive (+) tumors, irrespective of PR status (highest intake [> or = 10 g of alcohol per day] versus nondrinkers, multivariable RR = 1.35, 95% confidence interval [CI] = 1.02 to 1.80; Ptrend < .049 for ER+PR+ tumors; and RR = 2.36, 95% CI = 1.56 to 3.56; Ptrend < .001 for ER+PR-tumors). The absolute rate of ER+ breast cancer (standardized to the age distribution of person-years experienced by all study participants using 5-year age categories) was 232 per 100,000 person-years among women in the highest category of alcohol intake, and 158 per 100,000 person-years among nondrinkers. No association was observed between alcohol intake and the risk of developing ER-tumors. Furthermore, we observed a statistically significant interaction between alcohol intake and the use of postmenopausal hormones on the risk for ER+PR+ tumors (Pinteraction = .039).

CONCLUSION

The observed association between risk of developing postmenopausal ER+ breast cancer and alcohol drinking, especially among those women who use postmenopausal hormones, may be important, because the majority of breast tumors among postmenopausal women overexpress ER.

Immunohistochemical study of androgen receptors in breast carcinoma. Evidence of their frequent expression in lobular carcinoma

Androgens and androgen receptors (AR) are involved in the pathogenesis of breast cancer. Epidemiological studies have shown a significant association between the risk of breast cancer and androgens. However, the functional role and clinical value of AR expression in breast carcinoma have still not been clearly defined. The present study was set up to investigate the prevalence of ARs in a series of consecutive invasive breast carcinomas (IBCs) and to evaluate the patterns of AR phenotypes in a series of selected invasive lobular carcinomas (ILCs). Among the 250 consecutive IBCs (consisting of 212 ductal and 38 lobular neoplasms), AR immunoreactivity was observed in 151/250 (60.4%) cases, being expressed in 118/212 (56%) ductal and 33/38 (87%) lobular carcinomas (a statistically significant difference, chi2=11.82). AR expression was frequently associated with ER (65.2%, chi2=14.33) and PR positivity (66.9%, chi2=7.36). Most AR positive cases showed a low proliferative index (63.7%) and a low or intermediate histological grade (G1-G2, 63.9%). Among the 80 selected ILCs, AR expression was observed in 64/80 (80%) cases. Our results confirm that ARs are expressed in most breast cancers. Moreover, we demonstrated that AR positivity is particularly marked in lobular neoplasms. In addition, AR positive carcinomas are frequently characterized by a low or intermediate grade, a low proliferative index and ER and/or PR co-expression.

Determination of threshold values for determining the size of the fraction of steroid hormone receptor-positive tumor cells in paraffin-embedded breast carcinomas

BACKGROUND

For 4 years we used a multiparameter DNA flow cytometric (MP-FCM) technique to assess steroid hormone receptor expression in the diagnostic workup of routinely processed formalin-fixed, paraffin-embedded breast carcinomas as an alternative to immunohistochemistry (IHC) for the quantification of hormone receptor-positive cells. In all cases a positive fraction of hormone receptor-expressing epithelial cells was detected. This observation raised the question of what the cutoff value might be to distinguish receptor-negative from receptor-positive tumors.

METHODS

In our search for a possible threshold value of positivity for estrogen receptor (ER) and progesterone receptor (PR) in MP-FCM, we developed four steps. First, we compared IHC results in our own laboratory with the results obtained by MP-FCM on a small series of breast tumors (n = 42). Second, after collecting our first 843 tumors, we made a comparison with the literature of the distribution of receptor positivity according to age classes. Third, using the most likely threshold that resulted from this comparison, we compared a subset of 340 node-negative tumors for their combined ER/PR profiles with the data from a similar group of node-negative tumor cases from the National Cancer Institute's Surveillance, Epidemiology and End-Result (SEER) study. Fourth, with the results of these comparisons, we prospectively collected IHC data and MP-FCM results of the same tumor samples for a period of 1 year. In this way, we collected data for an additional 180 tumors.

RESULTS

The first step in this process resulted in an previous publication where 20% of steroid hormone receptor-positive cells seemed to be an acceptable cutoff point for positivity. However, the second step provided the best correlation at approximately 35% of ER reactive cells in the cytokeratin-positive cell population. With this cutoff, the distribution of combined ER/PR profiles in our patient population of node-negative breast cancers also showed a distribution similar to the data from the SEER study. The fourth step, using the 35% threshold value, resulted in a good correlation (r = 0.85, P < 0.0001) for ER and PR between IHC and MP-FCM in the 180 tumors investigated.

CONCLUSION

By comparing in-house data with those from large external data collections in the literature, a threshold percentage can be defined that distinguishes steroid hormone receptor-negative from hormone receptor-positive tumors. As a result, information about DNA content and cell cycle distribution can be obtained. This observational study provides additional support to our opinion that MP-FCM is an alternative for IHC determination of ER and PR positivity. It is more objective and quantification can be done more appropriately. The additional value of this approach is that we generate continuous variables of ER/PR content instead of categorical classes, which can be used at different threshold levels for evaluation of clinical relevance.

Folate Intake and Risk of Breast Cancer Characterized by Hormone Receptor Status

Folate plays an important role in DNA methylation, and aberrant methylation of the estrogen receptor (ER) gene may be related to the loss of ER gene expression in breast tumors. Thus, deficient folate status has been hypothesized to be associated primarily with ER gene-negative breast tumors, but data relating folate intake to breast cancer risk according to ER status are sparse. We conducted a prospective cohort analysis of folate intake among 88,744 women in the Nurses' Health Study who completed a food frequency questionnaire in 1980 and every 2 to 4 years thereafter. During 20 years of follow-up, 2,812 ER+ and 985 ER- invasive breast cancer cases were documented. Higher total folate intake was significantly associated with lower risk of developing ER- but not ER+ breast cancer; the multivariable relative risks (RR) and 95% confidence intervals (95% CI) comparing the highest to the lowest quintile were 0.81 (0.66-0.99) for ER- tumors and 1.00 (0.89-1.14) for ER+ tumors. The inverse association between total folate intake and ER- breast cancer was mainly present among women consuming at least 15 g/d of alcohol (multivariable RR, 0.46; 95% CI,=0.25-0.86; top versus bottom quintile). These findings support the hypothesis that higher folate intake reduces the risk of developing ER- breast cancer. Ensuring adequate folate intake seems particularly important for women at higher risk of breast cancer because of alcohol consumption.

Immunoreactive estrogen receptor in breast tumor and adjacent tissue: association with clinicopathological characteristics in Indian population

BACKGROUND AND OBJECTIVES

Estrogen receptor (ER) status serves as an important prognostic marker in the management of breast cancer. The level of ER in breast tumor is different in different racial and ethnic groups. In the present study, we have compared the ER levels in breast tumor and adjacent normal tissue in Indian sub-population.

METHODS

Immunoreactive ER was measured by enzyme immunoassay in breast tumors (ERt) and adjacent area (ERa) derived from 45 breast cancer patients from North India. Clinical parameters like age, menopausal status, tumor stage, recurrence and treatment status were recorded.

RESULTS

A significant positive correlation was observed between the levels of ERt and ERa (r = 0.386, P = 0.009). While the ERt levels increased with advancing age (P = 0.087), the ERa levels did not change in different age groups. The ERt levels negatively correlated with tumor stage and recurrence (r = -0.263, P = 0.110 and r = -0.202, P = 0.189). A significant negative correlation was also observed between the ERa levels and tumor recurrence (r = -0.337, P = 0.025). Further, the ERt positivity was higher than the ERa positivity. The clinical characteristics like age, tumor stage, metastasis, recurrence, and treatment status did not correlate with ERt and ERa positivity.

CONCLUSIONS

The present study shows that the levels of ERt and ERa positively correlate and both ERt and ERa show negative correlation with tumor recurrence.

Endogenous coactivator ARA70 interacts with estrogen receptor alpha (ERalpha) and modulates the functional ERalpha/androgen receptor interplay in MCF-7 cells

Overexpression of androgen receptor (AR) decreases estrogen receptor alpha (ERalpha) transactivation, which plays a basic role in hormone-dependent breast cancer. This transcriptional interference can be due to shared coactivators. Here we demonstrated that in MCF-7 cells ARA70, an AR-specific coactivator, interacted with endogenous ERalpha, increasing its transcriptional activity, and it was recruited to the pS2 gene promoter. Moreover, a dominant negative ARA70 down-regulated ERalpha transcriptional activity as well as pS2 mRNA. ARA70 overexpression reversed the AR down-regulatory effect on ERalpha signaling. However, in the presence of a progressive increase of transfected AR, ARA70 switched into enhancing the inhibitory effect of AR on ERalpha signaling. These opposite effects of ARA70 were further evidenced by coimmunoprecipitation assay in MCF-7wt, MCF-7-overexpressing AR, and HeLa cells, exogenously expressing an excess of ERalpha with respect to AR or an excess of AR with respect to ERalpha. Thus, ARA70 is a coactivator for ERalpha and may represent a functional link between ERalpha/AR modulating their cross-talk in models of estrogen signaling in MCF-7 and HeLa cells.

Estrogen receptor status in BRCA1- and BRCA2-related breast cancer: the influence of age, grade, and histological type

PURPOSE

BRCA1-related breast cancers are more frequently estrogen receptor (ER) negative than are either BRCA2-related or nonhereditary breast cancers. The relationship between ER status and other clinical features of hereditary breast cancers has not been well studied.

EXPERIMENTAL DESIGN

ER status, grade, and histological tumor type were evaluated in 1131 women with invasive breast cancer, ascertained at 10 centers in North America. There were 208 BRCA1 mutation carriers, 88 BRCA2 carriers, and 804 women without a known mutation. We stratified the patients by mutation status, grade, age, and histological type and calculated the percentage of ER-positive tumors within each stratum.

RESULTS

BRCA1 mutation carriers were more likely to have ER-negative breast cancers than were women in other groups, after adjustment for age, grade, and histological subtype (P < 0.001). Only 3.9% of BRCA1-related breast cancers were ER-positive cancers occurring in women in their postmenopausal years. The direction and magnitude of the change in ER status with increasing age at diagnosis in BRCA1 carriers was significantly different from in BRCA2 carriers (P(intercept) = 0.0002, P(slope) = 0.04). Notably, changes in ER status with age at diagnosis for BRCA1 carriers and noncarriers were almost identical (P(slope) = 0.98).

CONCLUSIONS

The strong relationship between the presence of a BRCA1 mutation and the ER-negative status of the breast cancers is neither a consequence of the young age at onset nor the high grade but is an intrinsic property of BRCA1-related cancers. The ER-negative status of these cancers may reflect the cell of origin of BRCA1-related cancers.

Alcohol Exposure and Breast Cancer: Results of the Women's Contraceptive and Reproductive Experiences Study

Objectives: To explore associated biological outcomes and clarify the role of timing of exposure in the alcohol-breast cancer relationship.

Methods: In a population-based study of 4,575 women ages 35 to 64 years diagnosed with invasive breast cancer between 1994 and 1998 and 4,682 controls, we collected details of lifetime alcohol use and factors that could confound or modify the alcohol-breast cancer relationship. We used conditional logistic regression to compute the odds of breast cancer among drinkers relative to nondrinkers at all ages and at ages 35 to 49 and 50 to 64 years separately.

Results: Recent consumption (at reference age minus two) of ≥7 drinks per week was associated with increased risk [odds ratio (OR), 1.2; 95% CI, 1.01-1.3] and evidence of dose response was observed. Most of the excess was observed among women ages 50-64 years (OR 1.3; 95% CI, 1.1-1.6), although the test for age interaction was not statistically significant. Exposure later in life seemed more important than early exposure. Excess breast cancer associated with recent consumption was restricted to localized disease. When outcome was examined according to tumor hormone receptor status, highest risks were observed for estrogen receptor–positive/progesterone receptor–negative tumors (OR 1.6; 95% CI, 1.2-2.3).

Conclusions: The effect of timing of alcohol exposure on breast cancer risk is complicated and will require additional study focused on this one issue. Further work is needed to explain how alcohol exposure, sex hormones, and tumor receptor status interact.

Receptor Imaging in Oncology by Means of Nuclear Medicine: Current Status

To date, our understanding of the role of receptors and their cognate ligands in cancer is being successfully translated into the design and development of an arsenal of new, less toxic, and more specific anticancer drugs. Because most of these novel drugs are cytostatic, objective response as measured by morphologic imaging modalities (eg, computed tomography or magnetic resonance imaging) cannot be used as a surrogate marker for drug development or for clinical decision making. Positron emission tomography (PET) can be used to image and quantify the in vivo distribution of positron-emitting radioisotopes such as oxygen-15, carbon-11, and fluorine-18 that can be substituted or added into biologically relevant and specific receptor radioligands. Similarly, single-photon emission computed tomography (SPECT) can be used to image and quantify the in vivo distribution of receptor targeting compounds labeled with indium-111, technetium-99m, and iodine-123. By virtue of their whole-body imaging capacity and the absence of errors of sampling and tissue manipulation as well as preparation, both techniques have the potential to address locoregional receptor status noninvasively and repetitively. This article reviews available data on the in vivo evaluation of receptor systems by means of PET or SPECT for identifying and monitoring patients with sufficient receptor overexpression for tailored therapeutic interventions, and also for depicting tumor tissue and determining the currently largely unknown heterogeneity in receptor expression among different tumor lesions within and between patients.

Role of vitamins in the risk, prevention, and treatment of breast cancer

PURPOSE OF REVIEW

This article presents an overview of the role of vitamins in the risk, prevention, and treatment of breast cancer, with emphasis on current evidence from English-language articles published since 1 August 2002 and indexed in MEDLINE.

RECENT FINDINGS

Findings from epidemiologic studies that have evaluated vitamin A and carotenoids in relation to breast cancer risk have been inconclusive. The available data, especially from prospective studies, do not support an association between vitamins E and C and risk of breast cancer. Recent studies suggest that folate plays an important role in the prevention of breast cancer, particularly among women consuming alcohol. Limited data also support a potential role of vitamin D in the prevention of breast cancer.

SUMMARY

High intake of folate or adequate circulating levels of folate may reduce the risk of breast cancer. Adequate folate levels may be particularly important for women who are at higher risk of breast cancer because of high alcohol consumption. The inverse association between vitamin D and risk of breast cancer needs to be evaluated in more studies.

The effect of the new SERM arzoxifene on growth and gene expression in MCF-7 breast cancer cells

The benzothiophene arzoxifene is a new 3rd generation selective estrogen receptor (ER) modulator (SERM). We have investigated the effect of arzoxifene on growth and gene expression in the estrogen receptor alpha (ERalpha) positive human breast cancer cell line MCF-7. Arzoxifene inhibits cell growth as effectively as the antiestrogen tamoxifen. Northern analysis revealed that arzoxifene exerts a statistically significant inhibition of pS2 and progesterone receptor B mRNA expression. Significant agonistic effect was observed on the antitrypsin mRNA expression. In contrast to estradiol and tamoxifen, arzoxifene does not upregulate cathepsin D mRNA and protein expression. The metabolite of arzoxifene (ARZm) is a more potent growth inhibitor of MCF-7 cells than arzoxifene. A tamoxifen resistant MCF-7 subline displayed a significant dose-dependent growth inhibition to ARZm, whereas an ICI 182,780 resistant cell line only responded to high concentration. Our results indicate that arzoxifene and especially ARZm are efficient growth inhibitors of ER positive human breast cancer cells, including tamoxifen resistant cells. Moreover, arzoxifene displays less estrogen agonistic effects in MCF-7 cells than tamoxifen.

Risk factors for breast cancer in young women by oestrogen receptor and progesterone receptor status

We used data from 765 cases and 564 controls in the population-based Australian Breast Cancer Family Study to investigate whether, in women under the age of 40, the profile of risk factors differed between breast cancer subtypes defined by joint oestrogen and progesterone receptor status. As hypothesised, no significant differences were found.

Breast carcinoma in women over the age of 85: distinct histological pattern and androgen, oestrogen, and progesterone receptor status

AIMS

The pathogenesis of breast carcinoma in very elderly women is of interest, because oestrogen levels are likely to be extremely low during the development of the disease. In an effort to understand the pathogenesis of breast carcinoma in these women, this study was undertaken to compare the histological patterns and hormone receptor status of breast carcinomas arising in very elderly and younger women.

METHODS AND RESULTS

Thirty-seven breast carcinomas from women over the age of 85 years at the time of their operation were examined histologically and compared with those from a large group of premenopausal women. The proportions of mucinous carcinoma and apocrine carcinoma were significantly greater in older women. The expression of steroid hormone receptors was studied immunohistochemically. Androgen receptor-positive carcinomas were significantly more frequent among older women, whereas progesterone receptor-positive carcinomas were significantly less frequent. There was no statistically significant difference in oestrogen receptor-alpha or -beta expression between the tumours from both groups.

CONCLUSION

Breast carcinomas in women over the age of 85 years have a different morphological spectrum from carcinomas in younger age groups and may have different pathogenesis mechanisms that may be more dependent on androgen and androgen receptor interaction. Differences from the results of the other studies are discussed.

Prognostic and predictive indicators in operable breast cancer

Because of its biological heterogeneity and wide spectrum of responsiveness to different treatments, breast cancer is a complex disease of difficult clinical management. Over the past several years, knowledge of the molecular mechanisms regulating normal and aberrant cell growth leading to cancer has been enhanced. These advances have enabled the identification of an increasing number of surrogate biomarkers, which have been correlated with prognosis or used as predictors of response to specific treatments. Axillary nodal status, age, tumor size, pathologic grade, and hormone receptor status are the established prognostic and/or predictive factors for selection of adjuvant treatments. The role of new biomarkers, such as p53, HER2/neu, angiogenesis, and the proliferation index value, is promising; however, the clinical value of their determination must be provided by prospective clinical studies.

Quantitative association between HER-2/neu and steroid hormone receptors in hormone receptor-positive primary breast cancer

BACKGROUND

HER-2/neu, which encodes a receptor tyrosine kinase, is amplified and overexpressed in 20%-25% of human breast cancers. Such tumors are often resistant to hormone therapy. Despite a general inverse association between HER-2/neu amplification/overexpression and estrogen receptor (ER) and/or progesterone receptor (PR) expression, a fraction of patients are both HER-2/neu- and hormone receptor (HR)-positive. The efficacy of hormone therapy in this group is currently a matter of debate. To better understand the relationship between HER-2/neu positivity and HR expression, we analyzed HER-2/neu, ER, and PR as continuous variables in breast cancer cell lines and two cohorts of primary breast cancer patients.

METHODS

HER-2/neu and ER/PR expression was analyzed by enzyme-linked immunosorbent assay (ELISA) and enzyme immunoassay (EIA), respectively, in 14 human breast cancer cell lines, some of which had been transfected with the HER-2/neu gene. For the clinical study population, HER-2/neu protein levels were assessed by ELISA (cohort A, n = 665), and HER-2/neu gene copy number was determined using fluorescence in situ hybridization (cohort B, n = 894). ER/PR expression was analyzed by EIA (cohort A) or radioligand binding (cohort B). Associations between HER-2/neu and ER/PR expression were analyzed using Spearman's rho correlation and the chi-square test, and absolute levels were compared using the Mann-Whitney U test. All statistical tests were two-sided.

RESULTS

HR-positive human breast cancer cell lines transfected with the HER-2/neu gene expressed statistically significantly lower levels of ER and PR than parental lines. In the clinical cohorts, levels of HER-2/neu overexpression and gene amplification were inversely correlated with ER/PR levels (Cohort A [n = 112]: for ER, r = -0.34, P<.001; for PR, r = -0.24, P =.010. Cohort B [n = 188]: for ER, r = -0.39, P<.001; for PR, r = -0.26, P<.001). Among patients with HR-positive tumors, HER-2/neu-positive tumors had statistically significantly lower ER/PR levels than HER-2/neu-negative ones (Cohort A: for ER, median = 25 fmol/mg [interquartile range [IQR] = 13-78] versus median = 38.5 fmol/mg [IQR = 17-99] and P =.031; for PR, median = 35 fmol/mg [IQR = 12-119] versus median = 88.5 fmol/mg [IQR = 22-236] and P<.001. Cohort B: for ER, median = 44 fmol/mg [IQR = 13-156] versus median = 92 fmol/mg [IQR = 35-235] and P<.001; for PR, median = 36 fmol/mg [IQR = 13-108] versus median = 84 fmol/mg [IQR = 24-250] and P<.001). Patients with higher levels of HER-2/neu overexpression or amplification had statistically significantly lower levels of ER/PR than patients with lower levels of HER-2/neu overexpression or amplification.

CONCLUSION

Because absolute HR levels are strongly related to response to hormone therapy in primary and advanced breast cancer, reduced ER/PR expression may be one mechanism to explain the relative resistance of HER-2/neu-positive:HR-positive tumors to hormone therapy.

Breast cancer: from estrogen to androgen receptor

To investigate the link existing between androgens and human breast cancer, the hormonal milieu present in pre- and post-menopausal women has been translated in an in vitro model utilizing a hormone dependent breast cancer cell line MCF-7 exposed to DHEA, DHEAS, androstenediol, T, DHT with or w/o E(2). DHEAS and androstenediol stimulate the growth of MCF-7 cell line but reduce cell proliferation induced by E(2) (1 nM). T and DHT (1-100 nM) instead inhibit MCF-7 cell proliferation independently on E(2) presence. When we focused our study on the most powerful androgen, DHT alone (100 nM) consistently inhibits MCF-7 cell proliferation by 50% of the basal growth rate and counteracts E(2) proliferative action by 68%. These data correlate well with cell cycle analysis showing an enhanced number of cells in G(0)/G(1) phase after 6 days of DHT treatment. Upon prolonged DHT exposure, Western blotting analysis shows a markedly increased AR content, while immunohistochemistry indicates that it was mostly translocated into the nucleus. So we assumed that the enhanced activation of the AR might inhibit MCF-7 cells proliferation. This assumption is corroborated by the fact that the inhibitory effects induced by DHT on MCF-7 cell proliferation are abrogated in the presence of hydroxyflutamide. Therefore to better investigate the role of AR in inhibiting E(2) action at genomic level, MCF-7 cells were transiently cotransfected with the reporter plasmid XETL carrying firefly luciferase sequence under the control of an estrogen responsive element and the full length AR or with an AR carrying a mutation (Cis 574-->Arg 574) which abolishes its binding to DNA. The over-expression of the AR markedly decreases E(2) signalling which furthermore appears inhibited by simultaneous exposure to DHT but reversed by addition of hydroxyflutamide. The inhibitory effect was no longer noticeable when MCF-7 cells were cotransfected with XETL and the mutant AR. Taken together these data demonstrate that gonadal androgens antagonize MCF-7 proliferation induced by E(2). This seems to be related to the inhibitory effects of the over-expressed AR on E(2) genomic action.

Natural history of estrogen receptor-negative, progesterone receptor-positive breast cancer

The biological significance of estrogen receptor-negative but progesterone receptor-positive breast carcinomas is not clear. In the present study the aggressiveness of breast carcinomas in relation to ER and PgR status has been investigated. The probability of disease-free survival in 297 node-negative breast carcinoma patients was monitored during a follow-up ranging from six to 96 months (median 45 months). Steroid hormone receptor content was assayed with the biochemical method recommended by the EORTC. The probability of disease-free survival was significantly worse for patients with ER-negative, PgR-positive carcinomas compared to the other three steroid hormone receptor phenotypes. Our results suggest that ER-negative, PgR-positive breast carcinomas are biologically different in terms of aggressiveness from the other steroid hormone receptor phenotypes.

Functionally active estrogen receptor isoform profiles in the breast tumors of African American women are different from the profiles in breast tumors of Caucasian women

BACKGROUND

Several cancer surveys have shown that African-American women (AAW) develop highly aggressive breast tumors and experience about three times higher mortality rates compared with other populations. Generally, breast tumors in AAW are poorly differentiated or undifferentiated and exhibit increased frequency of nuclear atypia, higher mitotic activity, higher S-phase fraction, and tumor necrosis. The molecular factors responsible for these tumor characteristics are mostly unknown.

METHODS

To explore whether the aggressive tumor biology observed in AAW is related to distinct alterations in estrogen receptor (ER) isoforms, the relative expression levels of four functionally active ER isoform mRNAs, ERalpha wild type, ERbeta wild type, ERalpha exon 3delta, and ERalpha exon 5delta, were measured by reverse transcriptase-polymerase chain reaction analysis in 18 immunohistochemically ERalpha positive tumors and in 6 ERalpha negative tumors and their matched normal tissues.

RESULTS

In the tumors of AAW, the protective ERbeta isoform was decreased significantly compared with matched normal tissues (paired t test; n = 24 patients; P = 0.0018). In addition, both the constitutively active ERalpha exon 5delta and the dominant negative ERalpha exon 3delta mRNA levels were elevated in tumor tissues compared with matched normal tissues (paired t tests; n = 24 patients; P = 0.0002 and P = 0.024, respectively).

CONCLUSIONS

The data presented here show for the first time that functionally active ER isoform profiles in the breast tumors of AAW are different from those in Caucasian women. The tumors in AAW are characterized by decreased levels of the protective ERbeta isoform and elevated levels of the constitutively active ERalpha exon 5delta isoform. Variations in estrogen-mediated signaling because of the alterations in these two ER isoforms may account in part for differences in tumor biology between AAW and Caucasian women.

HER2 as a prognostic and predictive marker for breast cancer

In recent years investigators have looked at the human epidermal growth factor receptor-2 (HER2), which is overexpressed in 20%-30% of breast cancer patients, with regard to its role as a prognostic and predictive factor. Although many studies have suggested that HER2 overexpression may be associated with a poor clinical outcome, other studies have not fully supported this observation. The inconsistencies between studies may be due in part to discrepancies between different HER2 testing methods. To overcome this problem, a radioimmunohistochemical method was developed to quantitatively measure HER2 overexpression levels in breast tumor samples. The application of this method demonstrated that 85% of all breast tumor samples expressed HER2 at levels greater than normal. Of these, 23% expressed HER2 at levels between 45 and 480 times greater than normal, and this was associated with poor clinical outcome. The investigation of HER2 status as a predictor of response to therapy has also yielded many conflicting results. Overall, it appears that HER2 overexpression may correlate with resistance to hormonal therapy, sensitivity to anthracycline-based chemotherapy and resistance to CMF. With the development of targeted anti-HER2 therapies, assessment of HER2 status will be important in stratifying patients to the most appropriate treatment regimens.

Analysis of the potential contribution of estrogen receptor (ER) beta in ER cytosolic assay of breast cancer

Estrogen receptor (ER) content is the most useful parameter for predicting hormone response therapy in breast cancer. Assays available for detecting ER in breast tumor cytosol are ligand-binding assay (LBA), which detects both ERalpha and ERbeta, and the enzymatic immunoassay (EIA), in which monoclonal antibodies are directed against ERalpha. As shown in several studies, the 2 assays correlate and both are used routinely. However, some discrepancies between the 2 assays were found and explanations remain controversial. We evaluated ERalpha and ERbeta mRNA coexpression in breast tumors in order to study whether the presence of ERbeta could account for differences between LBA and EIA in the determination of ER protein level. Using HeLa cell lines transfected with either ERalpha or ERbeta, we confirmed that EIA, using H222 and D547 monoclonal antibodies, recognizes only ERalpha expression, whereas LBA detects both isoforms. In 119 breast tumor cytosols, the correlation between ER-EIA and ER-LBA was high (r = 0.72), although some discrepancies were found. When analyzing ER mRNA expression of samples with higher LBA values, no overexpression of ERbeta mRNA relatively to ERalpha mRNA were observed. There was a difference in ERbeta/ERalpha ratio between ER-negative and ER-positive samples, with a 10-fold increased median ratio in ER-negative samples (p = 0.01). We thus confirmed that the major form of ER in breast cancer is the ERalpha at both the protein and mRNA levels. Moreover, our data do not support the hypothesis that ERbeta expression could explain differences between LBA and EIA in the determination of ER protein level.

Frequency distributions of breast cancer characteristics classified by estrogen receptor and progesterone receptor status for eight racial/ethnic groups

BACKGROUND

The National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) cancer registries have been collecting data regarding estrogen receptor (ER) and progesterone receptor (PR) status in breast cancer since 1990. The current study reports on some of these data for eight racial/ethnic groups.

METHODS

Stratified by ER and PR status, the frequency distributions of 112,588 breast cancer cases diagnosed between 1992--1997 in 11 SEER cancer registries were examined by age at diagnosis, stage at diagnosis, histologic grade, and tumor type for white, black, Hispanic, Japanese, Chinese, Filipino, Native Hawaiian, and American Indian and Alaska Native (AI/AN) females.

RESULTS

For each racial/ethnic group, the percentage of ER positive (+)/PR+ was > ER-PR- > ER+PR- > ER-PR+ tumors. For the two major ER/PR groups, the ER+PR+ tumors were different from the ER-PR- tumors in several ways. For white females, there were differences in the age distributions, stage at diagnosis, and histologic grade. For black females, the differences involved the age distributions and tumor grades. For Hispanic and Japanese females, there were differences with regard to the age distributions and tumor grades. For Filipino, Chinese, and AI/AN females, the tumor stages and grades differed. For Native Hawaiians, the histologic tumor grades were different.

CONCLUSIONS

For each racial/ethnic group, the ER/PR status appeared to divide breast cancer patients into two or more subgroups with unique tumor characteristics. In general, ER status appeared to have the greatest impact on delineating these subgroups, whereas in some cases, PR status was able to modify the subgroups further. It is hoped that reporting these tumor characteristics by ER/PR status for each racial/ethnic group will spur more investigation into the significance of ER/PR status in each racial/ethnic group.

Postmenopausal obesity as a breast cancer risk factor according to estrogen and progesterone receptor status (Japan)

There have been inconsistent results on the association of postmenopausal obesity with breast cancer risk according to the estrogen (ER) and/or progesterone receptor (PR) status in the breast tissue, and this requires further evaluation. This study was designed to assess whether postmenopausal obesity differs according to receptor status. Information on risk factors was obtained from 1154 breast cancer cases and 21714 controls at Aichi Cancer Center Hospital, Nagoya, Japan between 1988 and 1992. The receptor status was known for 40% of cases. Obese postmenopausal women showed an increased risk of breast cancer (odds ratio (OR) for 5 kg of current weight=1.17, 95% confidence interval (CI)=1.10-1.25; OR for 1 kg/m(2) of body mass index (BMI)=1.07, 95% CI=1.04-1.10). The elevated OR was strongest for ER-positive, as well as with PR-positive, breast cancer among postmenopausal women who had a high BMI. The risk did not differ significantly according to ER status. However, obesity indices among postmenopausal women differed with borderline significance according to PR status. These results are consistent with the hypothesis that there is a gradient of risk for postmenopausal obesity according to hormonal receptor status, at least for PR status, although this was not statistically significant.

Preoperative hormone therapy trials for breast cancer

Preoperative hormone therapy for breast cancer has the potential to downstage a primary tumour hence increasing operability as well as making breast conservation feasible. Whether it will achieve any clinically significant survival benefit remains to be elucidated. Preoperative hormone therapy, in contrast to neoadjuvant chemotherapy, produces less severe side effects and can be continued throughout the perioperative period. Presurgical studies have demonstrated anti-tumour effects of hormone therapy, e.g. down-regulation of ER. Current clinical trials have shown that, in patients with ER positive tumours, a response approaching 70% is reached in approximately three months using the traditional hormonal agent tamoxifen. The tumour seldom progresses during this period. New agents (such as third generation aromatase inhibitors and pure anti-oestrogens) may produce more profound and rapid responses. Future trials are required to identify factors other than ER to precisely predict response so that appropriate patients can be selected. The best agents, the ideal methods of monitoring response and the optimum duration of therapy also need to be identified. Clinical trials also need to test if pre- and perioperative hormone therapy is superior to conventional adjuvant hormone therapy in patients with early breast cancer.

Tumor variants by hormone receptor expression in white patients with node-negative breast cancer from the surveillance, epidemiology, and end results database

PURPOSE

Hormone receptor expression (presence-positive or absence-negative) may reflect different stages of one disease or different breast cancer types. Determining whether hormone receptor expression represents one or more breast cancer phenotypes would have important paradigmatic and practical implications.

METHODS

Breast cancer records were obtained from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database. The study included 19,541 non-Hispanic white women with node-negative breast cancer. Standard tumor cell characteristics and breast cancer-specific survival were analyzed by independent estrogen receptor (ER+ and ER-), independent progesterone receptor (PR+ and PR-), and joint ERPR expression (ER+PR+, ER+PR-, ER-PR+, and ER-PR-).

RESULTS

Age frequency density plots by hormone receptor expression showed two overlapping breast cancer populations with early-onset and/or late-onset etiologies. Independent ER+ and PR+ phenotype were associated with smaller tumor sizes, better grade, and better cancer-specific survival than ER- and PR- breast cancer types. Joint ERPR phenotype exhibited biologic gradients for tumor size, grade, and cancer-specific survival, which ranked from good to worse for ER+PR+ to ER+PR- to ER-PR+ to ER-PR-.

CONCLUSION

Variations of standard tumor cell characteristics and breast cancer-specific survival by hormone receptor expression in white patients with node-negative breast cancer suggested two breast cancer phenotypes with overlapping etiologies and distinct clinical features.

Hormonal receptor determination of 1,052 Chinese breast cancers

BACKGROUND AND OBJECTIVES

Hormonal receptors are important prognostic factors for breast cancer. The reported figures in the literature are mostly on Caucasians. This study analyzes the receptor profile of 1,052 Chinese patients.

METHODS

The age of the patients ranged from 20-93 years; 48% were premenopausal and 52% postmenopausal. Estrogen receptor (ER) and progesterone receptor (PgR) were measured quantitatively by enzyme immunoassay (EIA) using the rat monoclonal antibody (ABBOTT ER-EIA). Specimens with values >15 fmol/mg were considered positive according to manufacturer's recommendation.

RESULTS

ER was positive in 53% and 61.6% of the pre- and postmenopausal women respectively (P < 0.0075); PgR was positive in 51.5% and 46.2% respectively (P > 0.05). The mean values of ER were higher for postmenopausal women (P < 0.0001) but the values for PgR were similar between the two groups (P > 0.05). When the values were analyzed with respect to age, there was an increasing trend for ER. No such trend was noted for PgR. Subgroup analysis showed that there were more ER+PgR+ tumors among postmenopausal than among premenopausal women. Tumors with dubious receptor status (ER+PgR- or ER-PgR+) were more prevalent at perimenopausal age.

CONCLUSIONS

Chinese patients have lower receptor values and positivity rates than those reported for Caucasians. Receptor-positive tumors tend to occur in postmenopausal women.