Prognostic and predictive value of centrally reviewed expression of estrogen and progesterone receptors in a randomized trial comparing letrozole and tamoxifen adjuvant therapy for postmenopausal early breast cancer: BIG 1-98

Evaluation of Biomarkers in Multifocal/Multicentric Invasive Breast Carcinomas

Background. The purpose of this study was to evaluate whether breast carcinoma biomarkers vary among separate tumor foci of multifocal/multicentric (MF/MC) breast carcinomas and whether this variation correlates with morphological features and tumor grade. Design. We reviewed the biomarker profiles of MF/MC invasive breast carcinomas diagnosed between January 2001 and June 2010 at our institution. Estrogen receptor (ER), progesterone receptor (PR), and human epidermal receptor protein (HER2) results were classified as positive or negative. Results. Out of the 51 patients included in the study, 6 cases had 2 tumor foci with different morphologies, 7 cases had 2 foci with similar morphology but different grades, and 38 cases had 2 tumor foci with similar morphologies and grades. Out of the 38 patients who had MF/MC tumors with the same morphology and grade, only 1 patient had a difference in ER and PR status between foci. Out of the 7 patients who had morphologically similar tumors with different grades, 4 had similar results in both tumor foci, 3 had different results for ER and PR, and another had differing results for HER2 between the foci. All 6 patients who had MF/MC foci with different morphologies exhibited similar ER, PR, and HER2 results between the foci. Conclusion. Regardless of the similarity in tumor morphology or grade, a small number of cases included foci that exhibited different tumor marker expression, which might affect the treatment strategy. Therefore, our results suggest that the evaluation of tumor markers in different foci should be considered in MF/MC tumors for accurate treatment strategies.

Lack of either estrogen or progesterone receptor expression is associated with poor survival outcome among luminal A breast cancer subtype

BACKGROUND

This study was designed to evaluate the impact of lack of either estrogen receptor (ER) or progesterone receptor (PR) on characteristics and outcomes among luminal A breast cancer subtype treated with endocrine with or without chemotherapeutic agents.

METHODS

The luminal A subtype was categorized into three subgroups: ER+/PR+, ER+/PR-, and ER-/PR+. All tumors were human epidermal growth factor receptor 2 (HER2) negative. Clinicopathological features and survival were analyzed using the Severance Hospital dataset (n = 1,180) and were validated by the nationwide Korean Breast Cancer Society (KBCS) registry (n = 9,916).

RESULTS

Despite the different distribution of ER/PR status, tumor stage, grade, and local therapies between the two datasets, similarly ER+/PR+ showed smaller size and good differentiation, ER+/PR- patients had the oldest age at diagnosis, and ER-/PR+ was associated with the youngest age at onset and grade III tumor. Single hormone receptor-positive subgroups demonstrated worse disease-related outcomes than the ER+/PR+ subgroup. These associations were confirmed by the KBCS dataset. This trend was also demonstrated in the subpopulation of 1,944 patients with Ki-67 < 14 %. Inferior survival of single receptor-positive tumors was more definite among node-positive patients even when receiving both chemo-endocrine therapies.

CONCLUSIONS

Current results suggest that the luminal A subtype is also heterogeneous and each subgroup has unique clinicopathologic characteristics. Lack of either ER or PR expression is associated with worse survival, especially among node-positive luminal A subtype.

Preoperative endocrine therapy with goserelin acetate and tamoxifen in hormone receptor-positive premenopausal breast cancer patients

BACKGROUND

The use of preoperative endocrine therapy for breast cancer has increased during the last decade. Although several studies have reported favorable response rates in postmenopausal women, its effectiveness in premenopausal women remains unknown. This study therefore aimed to evaluate the potential benefits of preoperative endocrine therapy in premenopausal women.

METHODS

Fifty-three patients with estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative invasive breast cancer were included in this study. Preoperative endocrine therapy with goserelin acetate and tamoxifen was administered for 3 months. Clinical evaluations were performed by ultrasonography before and after endocrine therapy. Pathological evaluations were performed using core biopsy and surgical specimens. Immunohistochemical evaluations of ER, progesterone receptor (PgR), HER2, and Ki-67 were performed before and after endocrine therapy.

RESULTS

Partial response (PR) was observed in 23 % (12/53) and progressive disease (PD) in 2 % (2/53) of patients. Significant suppression of Ki-67 was observed following endocrine therapy in 90 % (47/52) of patients (P < 0.0001). Significant downregulation of PgR was observed after endocrine therapy (P = 0.0002), which tended to be correlated with clinical response (P = 0.058).

CONCLUSIONS

Three months of preoperative endocrine therapy with goserelin acetate and tamoxifen was safe and effective in premenopausal patients with invasive breast cancer, with a 23 % PR rate. Changes in PgR and Ki-67 expression might be promising markers for endocrine responsiveness.

Adding hormonal therapy to chemotherapy and trastuzumab improves prognosis in patients with hormone receptor-positive and human epidermal growth factor receptor 2-positive primary breast cancer

Adjuvant hormonal therapy for hormone receptor (HR)-positive primary breast cancer patients and a human epidermal growth factor receptor 2 (HER2)-targeted agent for HER2-positive primary breast cancer patients are standard treatment. However, it is not well known whether adding hormonal therapy to the combination of preoperative or postoperative chemotherapy and HER2-targeted agent contributes any additional clinical benefit in patients with HR-positive/HER2-positive primary breast cancer regardless of cross-talk between HR and HER2. We retrospectively reviewed records from 897 patients with HR-positive/HER2-positive primary breast cancer with clinical stage I-III disease who underwent surgery between 1988 and 2009. We determined the overall survival (OS) and disease-free survival (DFS) rates according to whether they received hormonal therapy or not and according to the type of hormonal therapy, tamoxifen and aromatase inhibitor, they received. The median followup time was 52.8 months (range 1-294.6 months). Patients who received hormonal therapy with chemotherapy and trastuzumab (n = 128) had significantly higher OS and DFS rates than did those who received only chemotherapy and trastuzumab (n = 46) in log-rank analysis (OS 96.1 vs. 87.0 %, p = 0.023, DFS 86.7 vs. 78.3 %, p = 0.029). There was no statistical difference in OS or DFS between those given an aromatase inhibitor and those given tamoxifen. In multivariate analysis, receiving hormonal therapy in addition to the combination of chemotherapy and trastuzumab was the sole independent prognostic factor for DFS (hazard ratio 0.446; 95 % CI 0.200-0.992; p = 0.048), and there was a similar trend in OS. Our study supported that hormonal therapy, whether in the form of an aromatase inhibitor or tamoxifen, confers a survival benefit when added to chemotherapy and trastuzumab in patients with HR-positive/HER2-positive primary breast cancer. Adjuvant treatment without hormonal therapy is inferior for this patient population.

Comparison of anti-estrogen receptor antibodies SP1, 6F11, and 1D5 in breast cancer: lower 1D5 sensitivity but questionable clinical implications

We compared the anti-estrogen receptors (ER) SP1, 6F11, and 1D5 antibodies in breast carcinoma cases with different ranges of positive cells to evaluate whether this could generate different therapies for patients. We selected 66 cases of breast cancer, each of which was immunostained with the 3 antibodies. 1D5 was less sensitive than SP1 and 6F11, as seen in 26, 20, and 21 negative cases, respectively. Nine cases showed differences in endocrine-therapy indications, of which 8 1D5-negative cases showed low positivity for SP1 and/or 6F11. However, these cases were prevalently G3, progesterone receptor-negative or low-positive, with high Ki-67 and positive HER-2 findings, all biological features associated with endocrine resistance. Finally ER values obtained with these 3 antibodies had no implications for chemotherapy.

PARP inhibitors--current status and the walk towards early breast cancer

Epithelial carcinomas in general arise as a result of the acquisition of and selection for multiple mutations in a parental somatic cell clone within the tissues of the primary organ of origin. In the last two decades genome caretakers, which function in key areas of DNA damage response, have been recognized as important tumour suppressor genes. Inactivating mutations in these genes occur both as germline and/or somatic mutations with increasing evidence of epigenetic silencing as an additional cause of loss of function. In any event, loss of function in a tumour cell pre-cursor clone leads to accelerated mutation acquisition and underpins the aetiology of the tumour. With increasing understanding of the complex network that is the DNA damage response, signaling pathways already recognized to be central to the establishment of the cancer phenotype are gaining additional roles as controllers of DNA repair. This has relevance to identification of wider populations of patients with tumours susceptible to approaches that target DNA repair deficiency. These have classically been with DNA damaging chemotherapy but the recently developed small molecule inhibitors of DNA repair enzymes such as Poly-ADP polymerases PARP-1 and PARP-2 have been shown to target tumour deficiencies in DNA repair as well sensitizing to DNA damaging therapeutics such as radiation and chemotherapy. Early phase trials with efficacy endpoints have been presented for the PARP inhibitors AG014699, olaparib, veliparib, iniparib and MK4827. The results of the first phase II trials exploring monotherapy PARP inhibitor strategies, which are based on revisiting the concept of synthetic lethality, have emerged and are reviewed herein. The clinical trials that have or are exploring combinations with DNA damaging therapy in these contexts are discussed with particular reference to breast cancer, as are biomarkers that have been proposed and are being investigated to develop optimal drug schedule and patient selection criteria for these DNA repair targeting approaches.

Systematic review on hormone receptor testing in breast cancer

Assessment of hormone receptors (estrogen and progesterone) helps to direct therapy for women with breast cancer. Immunohistochemistry is most commonly used to assess hormone receptor status and it is essential that these tests are performed accurately and reliably within and across laboratories. The overall purpose of this guideline is to improve the quality and accuracy of hormone receptor testing and its utility as a prognostic and predictive marker for invasive and in situ breast cancer. Medline, EMBASE, the Cochrane Database of Systematic Reviews, and abstracts from the San Antonio Breast Cancer Symposium were searched. An environmental scan of the internet and of international guideline developers and key organizations was performed. Preanalytic elements such as the collection, fixation, and storage of samples, and analytic elements such as selection of antibodies and scoring methods that seem to offer the best results for immunohistochemical assessment of hormone receptors are presented. Proficiency testing or quality assurance of immunohistochemistry is described.

Cancer care Ontario guideline recommendations for hormone receptor testing in breast cancer

Hormone receptor testing (oestrogen and progesterone) in breast cancer at the time of primary diagnosis is used to guide treatment decisions. Accurate and standardised testing methods are critical to ensure the proper classification of the patient's hormone receptor status. Recommendations were developed to improve the quality and accuracy of hormone receptor testing based on a systematic review conducted jointly by the American Society of Clinical Oncology/College of American Pathologists and Cancer Care Ontario's Program in Evidence-Based Care. Evidence-based recommendations were formulated to set standards for optimising immunohistochemistry in assessing hormone receptor status, as well as assuring quality and proficiency between and within laboratories. A formal external review was conducted to validate the relevance of these recommendations. It is anticipated that widespread adoption of these guidelines will further improve the accuracy of hormone receptor testing in Canada.

ESR1 gene status correlates with estrogen receptor protein levels measured by ligand binding assay and immunohistochemistry

The Estrogen Receptor (ER) is an established predictive marker for the selection of adjuvant endocrine treatment in early breast cancer. During the 1990s Immunohistochemistry (IHC) replaced cytosol based assays for determination of ER status. This study examined the association between ER protein level determined by two different methods and ESR1 gene copy number. From 289 primary high-risk breast cancer patients, randomized in the Danish Breast Cancer Cooperative Group (DBCG) 77C trial, results from cytosolic ER levels were available from ligand binding assays. Archival tumor tissue was retrieved from 257 patients. ESR1/CEN-6 ratio was analyzed successfully by Fluorescence In Situ Hybridization (FISH) in 220 (86%) patients. ESR1 amplification (ESR1/CEN-6 ≥ 2.00) was observed in 23% of the patients and ESR1 deletion (ESR1/CEN-6 < 0.80) was observed in 32%. Further, we identified ESR1 gain (ratio ESR1/CEN-6 from 1.30 to 1.99) in 19% of the patients. A positive correlation of ESR1 FISH with both ER-cytosol and ER IHC was found (p < 0.0001). Amplification and gain of the ESR1 gene are associated with higher ER protein content measured by ligand binding assay and a more intense nuclear staining by IHC compared to tumors with normal ESR1 gene status. Major variations in ER measured by ligand binding assay and IHC are observed within all ESR1 copy number subgroups and other mechanisms than gene copy number seem to contribute to the ER protein content in the tumors.

Prognostic and predictive role of ESR1 status for postmenopausal patients with endocrine-responsive early breast cancer in the Danish cohort of the BIG 1-98 trial

BACKGROUND

Estrogen Receptor 1 (ESR1) aberrations may be associated with expression of estrogen receptor (ER) or progesterone receptor (PgR), human epidermal growth factor receptor-2 (HER2) or Ki-67 labeling index and prognosis.

PATIENTS AND METHODS

ESR1 was assessed in 1129 (81%) of 1396 postmenopausal Danish women with early breast cancer randomly assigned to receive 5 years of letrozole, tamoxifen or a sequence of these agents in the Breast International Group 1-98 trial and who had ER ≥ 1% after central review.

RESULTS

By FISH, 13.6% of patients had an ESR1-to-Centromere-6 (CEN-6) ratio ≥ 2 (amplified), and 4.2% had ESR1-to-CEN-6 ratio <0.8 (deleted). Deletion of ESR1 was associated with significantly lower levels of ER (P < 0.0001) and PgR (P = 0.02) and more frequent HER2 amplification. ESR1 deletion or amplification was associated with higher-Ki-67 than ESR1-normal tumors. Overall, there was no evidence of heterogeneity of disease-free survival (DFS) or in treatment effect according to ESR1 status. However, significant differences in DFS were observed for subsets based on a combination of ESR1 and HER2 status (P = 0.02).

CONCLUSIONS

ESR1 aberrations were associated with HER2 status, Ki-67 labeling index and ER and PgR levels. When combined with HER2, ESR1 may be prognostic but should not be used for endocrine treatment selection in postmenopausal women with endocrine-responsive early breast cancer.

The enhanced antiproliferative response to combined treatment of trichostatin A with raloxifene in MCF-7 breast cancer cells and its relevance to estrogen receptor β expression

Antiestrogen is one type of the endocrine therapeutic agents for estrogen receptor α (ERα)-positive breast cancer. Unfortunately, this treatment alone is insufficient. Here we reported a novel potential anticancer strategy by using histone deacetylase (HDAC) inhibitor to enhance the action of endocrine therapy in ERα-positive breast cancer cell. The well-described HDAC inhibitor, trichostatin A (TSA), and antiestrogen raloxifene were found to, respectively, inhibit E2-induced proliferation of MCF-7 breast cancer cell in a dose-responsive and time-dependent manner. TSA and raloxifene enhanced the antiproliferative activity of each other by promoting cell death via apoptosis and cell cycle arrest. Thus, they displayed better antiproliferative effects in combined treatment than that with either agent alone. The expression level of estrogen receptor β (ERβ) showed a marked increase after TSA or/and raloxifene treatment. Treatments with TSA or/and raloxifene resulting in the up-regulation of ERβ are in accordance with the antiproliferative effects of the two agents. Furthermore, the over-expression of ERβ by adenovirus delivery could inhibit the proliferation of MCF-7 tumor cells and drastically enhanced the antiproliferative effects of TSA and raloxifene. These results demonstrated that the interference of ERβ on the antiproliferative effects of HDAC inhibitor and antiestrogen constitutes a promising approach for breast cancer treatment.

Membrane progesterone receptor alpha as a potential prognostic biomarker for breast cancer survival: a retrospective study

Classically, the actions of progesterone (P4) are attributed to the binding of nuclear progesterone receptor (PR) and subsequent activation of its downstream target genes. These mechanisms, however, are not applicable to PR– or basal phenotype breast cancer (BPBC) due to lack of PR in these cancers. Recently, the function of membrane progesterone receptor alpha (mPRα) in human BPBC cell lines was studied in our lab. We proposed that the signaling cascades of P4→mPRα pathway may play an essential role in controlling cell proliferation and epithelial mesenchymal transition (EMT) of breast cancer. Using human breast cancer tissue microarrays, we found in this study that the average intensity of mPRα expression, but not percentage of breast cancer with high level of mPRα expression (mPRα-HiEx), was significantly lower in the TNM stage 4 patients compared to those with TNM 1–3 patients; and both average intensities of mPRα expression and mPRα-HiEx rates were significantly higher in cancers negative for ER, as compared with those cancers with ER+. However, after adjusting for age at diagnosis and/or TNM stage, only average intensities of mPRα expression were associated with ER status. In addition, we found that the rates of mPRα-HiEx were significantly higher in cancers with epithelial growth factor receptor–1 (EGFR+) and high level of Ki67 expression, indicating positive correlation between mPRα over expression and EGFR or Ki67. Further analysis indicated that both mPRα-HiEx rate and average intensity of mPRα expression were significantly higher in HER2+ subtype cancers (i.e. HER2+ER–PR–) as compared to ER+ subtype cancers. These data support our hypothesis that P4 modulates the activities of the PI3K and cell proliferation pathways through the caveolar membrane bound growth factor receptors such as mPRα and growth factor receptors. Future large longitudinal studies with larger sample size and survival outcomes are necessary to confirm our findings.

Significance of histomorphology of early triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a heterogeneous disease. Possibly genetic characterisation provides the most appropriate information on tumour biology and prognosis, but it is only limitedly available in clinical practice. The aim of this investigation was to explore what additional prognostic information could be gained from detailed histomorphologic report.

PATIENTS AND METHOD

patients were selected retrospectively operated from 2005 to 2009 in one institution and charts were revised. Beyond age, tumour and nodal status, histologic grade and therapy, the additional pathologic characteristics were also involved in analysis: necrosis, lymphocytic infiltration, peritumoural vascular invasion (PVI), perineural invasion, DCIS extent and grade, perinodal spread, mitotic activity index (MAI).

RESULTS

295 early TNBC were involved. In univariate survival analysis with a mean follow-up of 3.57 years the tumour size, the nodal status, type of operation (conservation or mastectomy), irradiation, PVI and perinodal spread proved to be significantly connected with both disease free survival (DFS) and breast cancer specific overall survival (BSOS), and necrosis and chemotherapy with BSOS. Necrosis analysed together with lymphocytic infiltrate showed greater predicting power. In multivariate analysis nodal metastasis, necrosis positive/lymphacytic infiltration negative status and lack of irradiation has significant negative impact on DFS (p = <0.0001 HR:1.98 [1.4-2.77], p = <0.017 HR:2.1 [1.1-3.8], p = <0.001 HR:0.25 [0.11-0.57], respectively) and BSOS (p = <0.0001 HR:2.47 [1.8-3.4], p = <0.017 HR:3.7 [1.6-8.2], p = <0.0017 HR:0.24 [0.1-0.58], respectively). For DFS perivascular invasion also showed significant effect (p = <0.042 HR:2.5 [1.0-6.0]). Nodal status was the strongest prognostic parameter but other histomorphologic parameters can be used for prognosis prediction.

The Effect of Cold Ischemia Time and/or Formalin Fixation on Estrogen Receptor, Progesterone Receptor, and Human Epidermal Growth Factor Receptor-2 Results in Breast Carcinoma

Aims. To compare the results of estrogen and progesterone receptors (ER, PR), and human epidermal growth factor receptor-2 (HER2) expression status on biopsy and excision specimens and to evaluate the effect of cold ischemia time and/or formalin fixation on these biomarkers. Methods. Breast carcinomas that were diagnosed between 2007 and 2009 by core needle biopsy, and subsequently excised in our institution, were included in the study. Data regarding the tumor morphology, grade, and ER, PR, and HER2 status were retrospectively collected from the pathology reports. Results. Five out of 149 (3.4%) cases with ER-positive receptor status in the biopsy specimen became ER-negative in the subsequent excision specimen. Nine out of 126 (7.1%) cases with PR-positive receptor status in the biopsy specimen became PR-negative in the excision specimen. Receptor status change was predominantly seen in tumors with low ER and PR receptor expression. HER2 results were consistent between biopsy and excision specimens in all cases tested. Conclusions. Cold ischemia time and/or formalin fixation affect mainly ER and PR testing with low Allred scores and support the implementation of the ASCO/CAP guidelines. HER2 results, however, were not affected in our limited number of patients.

Estrogen Receptor (ER) mRNA and ER-Related Gene Expression in Breast Cancers That Are 1% to 10% ER-Positive by Immunohistochemistry

Purpose

We examined borderline estrogen receptor (ER) –positive cancers, defined as having 1% to 10% positivity by immunohistochemistry (IHC), to determine whether they show the same global gene-expression pattern and high ESR1 mRNA expression as ER-positive cancers or if they are more similar to ER-negative cancers.

Patients and Methods

ER status was determined by IHC in 465 primary breast cancers and with the Affymetrix U133A gene chip. We compared expressions of ESR1 mRNA and a 106 probe set ER-associated gene signature score between ER-negative (n = 183), 1% to 9% (n = 25), 10% (n = 6), and more than 10% (n = 251) ER-positive cancers. We also assessed the molecular class by using the PAM50 classifier and plotted survival by ER status.

Results

Among the 1% to 9%, 10%, and more than 10% ER IHC–positive patients, 24%, 67%, and 92% were also positive by ESR1 mRNA expression. The average ESR1 expression was significantly higher in the ≥ 10% ER-positive cohorts compared with the 1% to 9% or ER-negative cohort. The average ER gene signature scores were similar for the ER-negative and 1% to 9% IHC-positive patients and were significantly lower than in ≥ 10% ER-positive patients. Among the 1% to 9% ER-positive patients, 8% were luminal B and 48% were basal-like; among the 10% ER-positive patients, 50% were luminal. The overall survival rate of 1% to 9% ER-positive patients with cancer was between those of patients in the ≥ 10% ER-positive and ER-negative groups.

Conclusion

A minority of the 1% to 9% IHC ER–positive tumors show molecular features similar to those of ER-positive, potentially endocrine-sensitive tumors, whereas most show ER-negative, basal-like molecular characteristics. The safest clinical approach may be to use both adjuvant endocrine therapy and chemotherapy in this rare subset of patients.

Can we replace the microscope with microarrays for diagnosis, prognosis and treatment of early breast cancer?

In recent years, molecular research has translated into remarkable changes for breast cancer diagnostics and therapeutics. Molecular tests such as Oncotype DX® and MammaPrint® have revolutionized the predictive and prognostic tools in the clinic. By stratifying the risk of recurrence for patients, the tests are able to provide clinicians with more information on the treatment outcomes of using chemotherapy, endocrine therapy or combination therapies for patients with genetic expression patterns. However, it is still questionable for clinical applications as some areas remain unclear; the true benefit still needs prospective evaluation. In this paper, the limitation and the possibility to replace traditional histopathologic features of molecular tests are discussed. At the moment, it seems there are still limitations that prevent microarrays from replacing the microscope for diagnosis, prognosis and treatment of early breast cancer. However, additional important clinical information is added to traditional histology and IHC determination of ER, PR and HER2 in terms of prognostic and predictive power.

Factors associated with concordant estrogen receptor expression at diagnosis and centralized re-assay in a Danish population-based breast cancer study

BACKGROUND

Estrogen receptor (ER) expression predicts tamoxifen response, which halves the risk of breast cancer recurrence. We examined clinical factors associated with concordance between ER expression at diagnosis and centralized re-assay, and the association of concordance with breast cancer recurrence.

MATERIAL AND METHODS

We used immunohistochemistry to assess ER expression on archived fixed, paraffin-embedded breast carcinoma tissue excised from women aged 35-69 years, diagnosed 1985-2001 in Jutland, Denmark. We calculated the percentage agreement, positive predictive value (PPV) and negative predictive value (NPV) of ER status at diagnosis and re-assay. We used logistic regression to investigate factors associated with concordance, and its association with recurrence (odds ratios (OR) and associated 95% confidence intervals (95%CI)).

RESULTS

ER was re-assayed in 91% of patients (n = 1530). Concordance was better in ER + than ER- tumors (PPV = 94% vs. NPV = 75%). Factors associated with concordance included menopausal status, tumor size, surgical procedure, diagnostic period, lymph node status and time to recurrence. ER + women at diagnosis who re-assayed ER + were less likely to have recurrent disease (OR = 0.49, 95% CI = 0.28, 0.86) than those who re-assayed ER-. In originally ER- women, concordance was not associated with recurrence (OR = 0.97, 95% CI = 0.66, 1.42).

CONCLUSIONS

Several clinical factors were associated with ER assay concordance. Some women were ineffectively treated with tamoxifen, or required but did not receive tamoxifen. We observed almost exactly the protective effect of endocrine therapy among tamoxifen-treated ER + women whose tumors expressed the ER on re-assay, compared with those ER- on re-assay. Diagnostic pathology results for ER + tumors appear a valid and useful resource for research studies. However, those for ER- tumors have lower validity. Study-specific considerations regarding the aims, diagnostic period, and consequences of including ER- patients with truly ER + disease ought to be examined when using diagnostic pathology results for ER- tumors in research studies.

Practical implications of gene-expression-based assays for breast oncologists

Gene-expression profiling has had a considerable impact on our understanding of breast cancer biology, and more recently on clinical care. Two statistical approaches underlie these advancements. Supervised analyses have led to the development of gene-expression signatures designed to predict survival and/or treatment response, which has resulted in the development of new clinical assays. Unsupervised analyses have identified numerous biological signatures including signatures of cell type of origin, signaling pathways, and of cellular proliferation. Included within these biological signatures are the molecular subtypes known as the 'intrinsic' subtypes of breast cancer. This classification has expanded our appreciation of the heterogeneity of breast cancer and has provided a way to sub-classify the disease in a manner that might have clinical utility. In this Review, we discuss the clinical utility of gene-expression-based assays and their technical potential as clinical tools vis-a-vis the performance of breast cancer biomarkers that are the current standard of care.

Triple negative breast cancer: proposals for a pragmatic definition and implications for patient management and trial design

In trials in triple negative breast cancer (TNBC), oestrogen and progesterone receptor negativity should be defined as < 1% positive cells. Negativity is a ratio of <2 between Her2 gene copy number and centromere of chromosome 17 or a copy number of 4 or less. In routine practice, immunohistochemistry is acceptable given stringent quality assurance. Triple negativity emerging after neoadjuvant treatment differs from primary TN and such patients should not enter TNBC trials. Patients relapsing with TN metastases should be eligible even if their primary was positive. Rare TN subtypes such as apocrine, adenoid-cystic and low-grade metaplastic tumours should be excluded. TN and basal-like (BL) signatures overlap but are not equivalent. Since the significance of basal cytokeratin or EGFR overexpression is not known and we lack validated assays, these features should not be used to subclassify TN tumours. Tissue collection in trials is mandatory so the effect on outcome of different tumour phenotypes and BRCA mutation can be explored. No prospective studies have established that TN tumours have particular sensitivity or resistance to any specific chemotherapy agent or radiation. TNBC patients should be treated according to tumour and clinical characteristics.

Individualization of treatment strategies

This section focuses on different aspects of the individualization of hormone treatment in breast cancer. This includes tumor-related biological factors such as expression of hormone receptors, HER-2, and Ki-67; host-related factors such as CYP2D6 or body mass index, and risk and/or development of specific toxicities and treatment adherence. The best predictor of response to hormonal interventions is the expression of hormone receptors, in particular, estrogen receptors. Treatment adherence and compliance are key factors and strategies aiming to identify and intervene when patients are at risk of abandoning treatment. Currently, routine assessment of CYP2D6 is not recommended to guide tamoxifen treatment. Likewise, there are no criteria regarding bone mass density, lipid profile, or arthralgias to recommend one class of agent versus another. Aromatase inhibitors should not be administered to patients who are pre- or perimenopausal.

Estrogen receptor degradation: a CUE for endocrine resistance?

Despite the undoubted success of adjuvant endocrine therapies that target the estrogen receptor pathway, not all women with estrogen receptor-positive breast cancer respond to these therapies, and many who initially respond will subsequently relapse. Deregulation of various aspects of estrogen receptor signaling has been highlighted as a mechanism of resistance and as a basis for alternative therapeutic approaches. However, a recent publication refocuses attention on the estrogen receptor itself by showing that the ubiquitin-binding CUE domain-containing protein 2 is a regulator of estrogen receptor protein degradation and a marker of endocrine resistance in breast cancer.

Impact of low estrogen/progesterone receptor expression on survival outcomes in breast cancers previously classified as triple negative breast cancers

PURPOSE

To evaluate the impact of low estrogen/progesterone receptor (ER/PR) expression and effect of endocrine therapy on survival outcomes in human epidermal growth factor receptor 2 (HER2)-negative tumors with ER/PR <10%, previously labeled as triple negative.

METHODS

In a retrospective review, 1257 patients were categorized according their ER/PR percentages into 3 groups, ER/PR <1% (group A), ER/PR 1% to 5% (group B), and ER/PR 6% to 10% (group C). Kaplan-Meier product limit method was used to estimate survival outcomes. Cox proportional hazards models was used to adjust for patient and tumor characteristics.

RESULTS

Groups A, B, and C had 897 (71.4%), 241 (19.2%), and 119 (9.4%) patients, respectively. After a median follow-up of 40 months there was no significant difference in 3-year recurrence-free survival (RFS): 64%, 67%, and 77% (P = .34) or overall survival (OS): 79%, 81%, and 88% (P = .33) for groups A, B, and C, respectively. ER/PR expression was not an independent predictor for RFS (hazard ratio [HR], 1.10; 95% confidence interval [CI], 0.86-1.39; P = .46 for group B, and HR, 0.96; 95% CI, 0.66-1.38; P = .81 for group C, compared with group A), or OS (HR, 1.11; 95% CI, 0.84-1.46; P = .46 for group B, and HR, 0.94; 95% CI, 0.63-1.42; P = .78 for group C, compared with group A). Endocrine therapy had no impact on survival outcomes (RFS: P = .10; OS: P = .45) among groups.

CONCLUSIONS

In this cohort, a low ER/PR level (1%-5%) does not appear to have any significant impact on survival outcomes. There was a tendency for survival advantages in the ER/PR 6% to 10% is seen. Benefit of endocrine therapy in these patients is unclear.

Interaction between goserelin and tamoxifen in a prospective randomised clinical trial of adjuvant endocrine therapy in premenopausal breast cancer

Ovarian ablation improves survival in premenopausal early breast cancer, but the potential added value by luteinizing hormone-releasing hormone (LHRH) agonists to tamoxifen is still not clear. The purpose of our study is to examine the efficacy of the LHRH agonist goserelin for adjuvant therapy of premenopausal breast cancer, the role of interaction between goserelin and tamoxifen and the impact of estrogen receptor (ER) content. A total of 927 patients were included in the Stockholm part of the Zoladex in Premenopausal Patients (ZIPP) trial. They were randomly allocated in a 2 × 2 factorial study design to goserelin, tamoxifen, the combination of goserelin and tamoxifen or no endocrine therapy for 2 years, with or without chemotherapy. This is formally not a preplanned subset analysis presenting the end point first event. In this Stockholm sub-study, at a median follow-up of 12.3 years, goserelin reduced the risk of first event by 32% (P = 0.005) in the absence of tamoxifen, and tamoxifen reduced the risk by 27% (P = 0.018) in the absence of goserelin. The combined goserelin and tamoxifen treatment reduced the risk by 24% (P = 0.021) compared with no endocrine treatment. In highly ER-positive tumours, there were 29% fewer events among goserelin treated (P = 0.044) and a trend towards greater risk reduction depending on the level of ER content. The greatest risk reduction from goserelin treatment was observed among those not receiving tamoxifen (HR: 0.52, P = 0.007). In conclusion, goserelin as well as tamoxifen reduces the risk of recurrence in endocrine responsive premenopausal breast cancer. Women with strongly ER-positive tumours may benefit more from goserelin treatment. The combination of goserelin and tamoxifen is not superior to either modality alone. With the limitations of a subset trial, these data have to be interpreted cautiously.

Relationship between estrogen receptor, progesterone receptor, HER-2 and Ki67 expression and efficacy of aromatase inhibitors in advanced breast cancer

BACKGROUND

Surprisingly few data are published on the relevance of even commonly used biomarkers of response to aromatase inhibitors (AIs) in advanced breast cancer. Here, we aim to determine the effectiveness of AIs in that setting according to quantitative levels of estrogen receptor (ER), progesterone receptor (PgR) and Ki67 or human epithelial growth factor receptor-2 (HER-2) status.

PATIENTS AND METHODS

ER, PgR, HER-2 and Ki67 protein expressions were centrally assessed in 177 archival formalin-fixed paraffin-embedded primary or locally recurrent breast tumours from women who subsequently received AI treatment of advanced disease.

RESULTS

Among ER-positive patients (n = 146), higher PgR, but not ER, levels were associated with increased time to AI treatment failure (TTF). Higher Ki67 staining was associated with decreased TTF. ER-positive/HER-2-positive patients showed a non-significant trend for decreased TTF compared with ER-positive/HER-2-negative patients. PgR level, but not Ki67, remained a significant predictor of TTF in multivariate analysis of ER-positive patients.

CONCLUSIONS

Higher PgR and Ki67 levels are significantly associated with increased and decreased TTF, respectively, in ER-positive patients receiving AI treatment of advanced disease. The higher proliferation seen in PgR-negative tumours does not explain the poorer clinical responsiveness of this subgroup.

Association between breast cancer subtypes and response to neoadjuvant anastrozole

Considerable heterogeneity exists amongst oestrogen receptor positive (ER+ve) breast cancer in both its molecular profile and response to therapy. Attempts to better define variation amongst breast tumours have led to the definition of four main "intrinsic" subtypes of breast cancer with two of these classes, Luminal A and B, composed almost entirely of ER+ve cancers. In this study we set out to investigate the significance of intrinsic subtypes within a group of ER+ve breast cancers treated with neoadjuvant anastrozole. RNA from tumour biopsies taken from 104 postmenopausal women before and after 2 weeks treatment with anastrozole was analyzed on Illumina 48K microarrays. Gene-expression based subtypes and risk of relapse (ROR) scores for tumours pre- and post-treatment were determined using the PAM50 method. Amongst pre-treatment samples, all intrinsic subtypes were found to be present, although luminal groups were represented most highly. Luminal A and B tumours obtained similar benefit from treatment, as measured by the proportional fall in the proliferation marker Ki67 upon treatment (mean suppression=75.5% vs 75.7%). Tumours classified as basal and Her2-like showed poor reductions in Ki67 upon treatment. Residual Ki67 staining after two weeks remained higher in the Luminal B group. ROR score was significantly associated with anti-proliferative response to AI and with clinical response. These results suggest that in the short-term, Luminal A and B tumours may gain similar benefit from an AI but that the higher residual Ki67 level seen in Luminal B is indicative of poorer long term outcome.

Estrogen receptor positive operable breast cancer: does menopausal status impact on HER2 and progesterone receptor status?

PURPOSE

The objective of the present study was to determine whether progesterone receptor (PgR) and human epidermal growth factor receptor 2 (HER2) status differs by menopausal status in estrogen receptor (ER)-positive breast cancers.

PATIENTS AND METHODS

We retrospectively analyzed the clinicopathological data of 588 with operable ER(+) breast cancers patients. ER, HER2 and PgR expression in the tumor specimens were examined by immunohistochemistry. The relationship between different variables was assessed by Pearson's χ(2) and Fisher's exact probability tests in univariate analyses. Logistic regression was used for multivariate analyses of relationship between HER2 expression and selected clinicopathological characteristics. Maximum likelihood estimates of the odds ratio (OR) were obtained and 95% confidence intervals (CI) were calculated.

RESULTS

In the postmenopausal women with ER(+) tumors, HER2 was independently inversely associated with PgR expression (P = 0.017; OR 3.02; 95% CI 1.22-7.49). An ER(+)/PgR(-) tumor was 3.02 times more likely to express HER2 than an ER(+)/PgR(+) tumor in the postmenopausal women. However, an ER(+) tumor in the premenopausal patients failed to show an independent relationship between HER2 and PgR.

CONCLUSION

Menopausal status played a very important role in determining HER2 and PgR status in ER(+) breast cancer patients. HER2 was independently inversely associated with PgR only in the postmenopausal women with ER(+) breast cancers but not in the premenopausal ones.

Interpreting Breast International Group (BIG) 1-98: a randomized, double-blind, phase III trial comparing letrozole and tamoxifen as adjuvant endocrine therapy for postmenopausal women with hormone receptor-positive, early breast cancer

The Breast International Group (BIG) 1-98 study is a four-arm trial comparing 5 years of monotherapy with tamoxifen or with letrozole or with sequences of 2 years of one followed by 3 years of the other for postmenopausal women with endocrine-responsive early invasive breast cancer. From 1998 to 2003, BIG -98 enrolled 8,010 women. The enhanced design f the trial enabled two complementary analyses of efficacy and safety. Collection of tumor specimens further enabled treatment comparisons based on tumor biology. Reports of BIG 1-98 should be interpreted in relation to each individual patient as she weighs the costs and benefits of available treatments.

Clinicaltrials.gov ID: NCT00004205.

Value of post-operative reassessment of estrogen receptor α expression following neoadjuvant chemotherapy with or without gefitinib for estrogen receptor negative breast cancer

The NICE trial was designed to evaluate the possible benefits of adding epidermal growth factor receptor targeted therapy to neoadjuvant chemotherapy in patients with estrogen receptor α (ER) negative and operable breast cancer. Preclinical data have suggested that signalling through the ErbB receptors or downstream effectors may repress ER expression. Here the authors investigated whether gefitinib, given neoadjuvant in combination with epirubicin and cyclophosphamide (EC), could restore ER expression. Eligible patients in the NICE trial were women with unilateral, primary operable, ER negative invasive breast cancer ≥ 2 cm. Material from patients randomized and completing treatment (four cycles of neoadjuvant EC plus 12 weeks of either gefitinib or placebo) in the NICE trial having available ER status both at baseline and after neoadjuvant treatment were eligible for this study. Tumors with indication of changed ER phenotype (based on collected pathology reports) were immunohistochemically reassessed centrally. 115 patients were eligible for this study; 59 patients in the gefitinib group and 56 patients in the placebo group. Five (4.3%) of 115 tumors changed ER phenotype from negative to positive. A change was seen in three patients in the gefitinib (5.1%) and in two patients in the placebo (3.6%) group with a difference of 1.51% (95% CI, -6.1-9.1). Results of the NICE trial have been reported previously. Post-operative reassessment of ER expression changed the assessment of ER status in a small but significant fraction of patients and should, whenever possible, be performed following neoadjuvant chemotherapy for ER negative breast cancer. Gefitinib did not affect the reversion rate of ER negative tumors.

Estrogen receptor and progesterone receptor as predictive biomarkers of response to endocrine therapy: a prospectively powered pathology study in the Tamoxifen and Exemestane Adjuvant Multinational trial

PURPOSE

The Tamoxifen and Exemestane Adjuvant Multinational (TEAM) trial included a prospectively planned pathology substudy testing the predictive value of progesterone receptor (PgR) expression for outcome of estrogen receptor-positive (ER-positive) early breast cancer treated with exemestane versus tamoxifen.

PATIENTS AND METHODS

Pathology blocks from 4,781 TEAM patients randomly assigned to exemestane versus tamoxifen followed by exemestane for 5 years of total therapy were collected centrally, and tissue microarrays were constructed from samples from 4,598 patients. Quantitative analysis of hormone receptors (ER and PgR) was performed by using image analysis and immunohistochemistry, and the results were linked to outcome data from the main TEAM trial and analyzed relative to disease-free survival and treatment.

RESULTS

Of 4,325 eligible ER-positive patients, 23% were PgR-poor (Allred < 4) and 77% were PgR- rich (Allred ≥ 5). No treatment-by-marker effect for PgR was observed for exemestane versus tamoxifen (PgR-rich hazard ratio [HR], 0.83; 95% CI, 0.65 to 1.05; PgR-poor HR, 0.85; 95% CI, 0.61 to 1.19; P = .88 for interaction). Both PgR and ER expression were associated with patient prognosis in univariate (PgR HR, 0.53; 95% CI, 0.43 to 0.65; P < .001; ER HR, 0.66; 95% CI, 0.51 to 0.86; P = .002), and multivariate analyses (P < .001 and P = .001, respectively). A trend toward a treatment-by-marker effect for ER-rich patients was observed.

CONCLUSION

Preferential exemestane versus tamoxifen treatment benefit was not predicted by PgR expression; conversely, patients with ER-rich tumors may derive additional benefit from exemestane. Quantitative analysis of ER and PgR expression provides highly significant information on risk of early relapse (within 1 to 3 years) during treatment.

Genomic signature of BRCA1 deficiency in sporadic basal-like breast tumors

About 10-20% of all breast carcinomas show a basal-like phenotype, while ∼ 90% of breast tumors from BRCA1-mutation carriers are of this subtype. There is growing evidence that BRCA1-mutated tumors are not just a specific subset of the basal-like tumors, but that (the majority of) basal-like tumors show a dysfunctional BRCA1 pathway. This has major treatment implications, because emerging regimens specifically targeting DNA repair mechanisms would then be most effective against these tumors. To further understand the involvement of BRCA1 deficiency in sporadic basal-like tumors, we investigated 41 basal-like tumors for BRCA1 mRNA expression by quantitative real-time polymerase chain reaction, BRCA1 promoter methylation, their genomic profile by array-CGH, and gene expression levels by whole genome expression arrays. Array-CGH results were compared to those of 34 proven BRCA1-mutated tumors. Basal-like tumors were subdivided into two equal groups: deficient and proficient in BRCA1 gene expression. The chromosomal makeup of BRCA1 deficient sporadic basal-like tumors was similar to that of BRCA1-mutated tumors. BRCA1 proficient sporadic basal-like tumors were more similar to nonbasal-like tumors. Only half of the basal-like breast tumors are actually deficient in BRCA1 expression. Gain of chromosome arm 3q is a marker for BRCA1 deficiency in hereditary and sporadic breast tumors.

Predictive value of pathological and immunohistochemical parameters for axillary lymph node metastasis in breast carcinoma

Background/Objective

While several prognostic factors have been identified in breast carcinoma, the clinical outcome remains hard to predict for individual patients. Better predictive markers are needed to help guide difficult treatment decisions. Axillary lymph node metastasis (ALNM) is one of the most important prognostic determinants in breast carcinoma; however, the reasons why tumors vary in their capability to result in axillary metastasis remain unclear. Identifying breast carcinoma patients at risk for ALNM would improve treatment planning. This study aimed to identify the factors associated with ALNM in breast carcinoma, with particular emphasis on basal-like phenotype.

Methods

Breast carcinoma patients (n = 210) who underwent breast conserving surgery and axillary lymph node dissection (ALND) (level I and II) or modified radical mastectomy were included in this study. Pathological and immunohistochemical data including individual receptor/gene status was collected for analysis. The basal phenotype status was ascertained using the basal cytokeratin markers CK5, CK14, CK17 and EGFR.

Results

ALNM was found in 55% (n = 116) of the patients. On univariate analysis, multicentric disease, large tumor size (>2 cm), vascular and lymphatic invasion, epithelial hyperplasia, necrosis, in situ carcinoma and perineural invasion were associated with higher risk for ALNM, whereas CK5, CK14, EGFR positivity and basal-like tumor type were associated with lower risk. On multivariate analysis, CK5 positivity (OR 0.003, 95%CI 0.000-0.23, p = 0.009) and lymphatic/vascular invasion (OR 17.94, 95%CI 4.78-67.30, p < 0.001) were found to be independent predictors.

Conclusions

Although the value of complete ALND has been questioned in invasive breast cancer patients, treatment decisions for breast carcinoma have been influenced by many parameters, including lymph node status. Since histopathologic characteristics and expression of biological markers varies among the same histologic subtypes of breast carcinoma, specific clinical and histopathologic features of the primary tumor and ALN status like sentinel node might be used to tailor the loco-regional and systemic treatment in different clinical settings.

A review of an unfavorable subset of breast cancer: estrogen receptor positive progesterone receptor negative

Estrogen receptor (ER)(+) progesterone receptor (PR)(-) tumors are a distinct subset of breast cancers characterized by aggressive behavior and tamoxifen resistance in spite of being ER(+). They are categorized as luminal B tumors and have greater genomic instability and a higher proliferation rate. High growth factor (GF) signaling and membranous ER activity contribute to the aggressive behavior of these tumors. The absence of PR is attributable to low serum estrogen, low levels of nuclear ER, and features of molecular crosstalk between GFs and membranous ER. PR expression is also downregulated by expression of mutated epidermal growth factor receptor (EGFRvIII). This subset of patients has greater expression of human epidermal growth factor receptor (HER)-1 and HER-2 and active GF signaling mediated by the phosphoinositide 3-kinase-Akt-mammalian target of rapamycin pathway. Currently, aromatase inhibitors, fulvestrant, and chemotherapy may be the favored treatment approaches for this subset of patients. Overcoming tamoxifen resistance with targeted therapies such as gefitinib is being evaluated and strategies involving short courses of tamoxifen have been postulated for prevention of recurrence of this subtype. Understanding the interplay between molecular endocrinology and tumor biology has provided experimental therapeutic insights, and continued work in this area holds the promise of future advances in prognosis.

Which patients benefit most from adjuvant aromatase inhibitors? Results using a composite measure of prognostic risk in the BIG 1-98 randomized trial

BACKGROUND

On average, aromatase inhibitors are better than tamoxifen when used as initial or sequential therapy for postmenopausal women with endocrine-responsive early breast cancer. Because there may be contraindications to their use based on side-effects or cost, we investigated subgroups in which aromatase inhibitors may be more or less important.

PATIENTS AND METHODS

Breast International Group 1-98 trial randomized 6182 women among four groups comparing letrozole and tamoxifen with sequences of each agent; 5177 (84%) had centrally confirmed estrogen receptor (ER) positivity. We assessed whether centrally determined ER, progesterone receptor (PgR), human epidermal growth factor receptor 2, and Ki-67 labeling index, alone or in combination with other prognostic features, predicted the magnitude of letrozole effectiveness compared with either sequence or tamoxifen monotherapy.

RESULTS

Individually, none of the markers significantly predicted differential treatment effects. Subpopulation treatment effect pattern plot analysis of a composite measure of prognostic risk revealed three patterns. Estimated 5-year disease-free survival for letrozole monotherapy, letrozole→tamoxifen, tamoxifen→letrozole, and tamoxifen monotherapy were 96%, 94%, 93%, and 94%, respectively, for patients at lowest risk; 90%, 91%, 93%, and 86%, respectively, for patients at intermediate risk; and 80%, 76%, 74%, and 69%, respectively, for patients at highest risk.

CONCLUSION

A composite measure of risk informs treatment selection better than individual biomarkers and supports the choice of 5 years of letrozole for patients at highest risk for recurrence.

Adjuvant tamoxifen and exemestane in early breast cancer (TEAM): a randomised phase 3 trial

BACKGROUND

Aromatase inhibitors improved disease-free survival compared with tamoxifen when given as an initial adjuvant treatment or after 2-3 years of tamoxifen to postmenopausal women with hormone-receptor-positive breast cancer. We therefore compared the long-term effects of exemestane monotherapy with sequential treatment (tamoxifen followed by exemestane).

METHODS

The Tamoxifen Exemestane Adjuvant Multinational (TEAM) phase 3 trial was conducted in hospitals in nine countries. Postmenopausal women (median age 64 years, range 35-96) with hormone-receptor-positive breast cancer were randomly assigned in a 1:1 ratio to open-label exemestane (25 mg once a day, orally) alone or following tamoxifen (20 mg once a day, orally) for 5 years. Randomisation was by use of a computer-generated random permuted block method. The primary endpoint was disease-free survival (DFS) at 5 years. Main analyses were by intention to treat. The trial is registered with ClinicalTrials.gov, NCT00279448, NCT00032136, and NCT00036270; NTR 267; Ethics Commission Trial27/2001; and UMIN, C000000057.

FINDINGS

9779 patients were assigned to sequential treatment (n=4875) or exemestane alone (n=4904), and 4868 and 4898 were analysed by intention to treat, respectively. 4154 (85%) patients in the sequential group and 4186 (86%) in the exemestane alone group were disease free at 5 years (hazard ratio 0·97, 95% CI 0·88-1·08; p=0·60). In the safety analysis, sequential treatment was associated with a higher incidence of gynaecological symptoms (942 [20%] of 4814 vs 523 [11%] of 4852), venous thrombosis (99 [2%] vs 47 [1%]), and endometrial abnormalities (191 [4%] vs 19 [<1%]) than was exemestane alone. Musculoskeletal adverse events (2448 [50%] vs 2133 [44%]), hypertension (303 [6%] vs 219 [5%]), and hyperlipidaemia (230 [5%] vs 136 [3%]) were reported more frequently with exemestane alone.

INTERPRETATION

Treatment regimens of exemestane alone or after tamoxifen might be judged to be appropriate options for postmenopausal women with hormone-receptor-positive early breast cancer.

FUNDING

Pfizer.

High estrogen receptor expression in early breast cancer: chemotherapy needed to improve RFS?

One of the most controversial questions in early breast cancer treatment is the need of chemotherapy in patients with estrogen receptor positive disease. Therefore, we analyzed a group of patients with high estrogen receptor (ER) expression to scrutinize the role of chemotherapy in this situation. To gauge the effect of chemotherapy on recurrence free survival (RFS) three treatment modalities were compared: endocrine treatment only, chemoendocrine treatment, and chemotherapy. 3,971 breast cancer patients whose treatment modalities as well as ER level were known, were included in this retrospective analysis. Their level of ER expression was documented as immunoreactive score (IRS). A high ER group was defined as ER IRS ≥ 9; primary endpoint was RFS. RFS was associated with ER, with the best outcome for strong and the worst result for negative expression. Adjusted to Nottingham prognostic index (NPI), RFS did not differ between the treatment cohorts of endocrine treatment and chemoendocrine treatment (P = 0.828) in the high ER group. Patients with chemotherapy alone fared significantly worse (P = 0.003). Even in high risk patients (according to NPI) the chemoendocrine and the endocrine treatment only groups did not differ significantly (HR = 1.15; 95% CI (0.56-2.34), P = 0.709). Omission of endocrine treatment led to significantly worse outcome (P = 0.013). In conclusion, RFS was significantly longer in patients with high ER expression than with weak or no ER expression. In the high expression group, there was no significant difference in RFS between endocrine treatment only and chemoendocrine therapy-even in high risk patients, for whom chemoendocrine treatment is routinely indicated. It seems insufficient for high ER patients to only consider tumor size, nodal status, and grading in order to decide which patient will benefit from adding chemotherapy to endocrine treatment.

Estrogen and progesterone receptor testing in breast carcinoma: concordance of results between local and reference laboratories in Brazil

CONTEXT AND OBJECTIVE

Breast cancer accounts for approximately one quarter of all cancers in females. Estrogen and progesterone receptor testing has become an essential part of the clinical evaluation of breast carcinoma patients, and accurate results are critical in identifying patients who may benefit from hormone therapy. The present study had the aim of investigating the concordance of the results from hormone receptor tests between a reference laboratory and local (or community) laboratories in Brazil.

DESIGN AND SETTING

Retrospective study at a reference pathology laboratory.

METHODS

The concordance in the results from hormone receptor tests between a reference laboratory and 146 local laboratories in Brazil was compared in relation to 500 invasive breast carcinoma cases, using immunohistochemistry.

RESULTS

There was concordance in 89.4% (447/500 cases) and 85.0% (425/500 cases) of the results from estrogen (κ = 0.744, P < 0.001) and progesterone (κ = 0.688, P < 0.001) receptor tests, respectively, between local and reference laboratories. This was similar to findings in other countries. The false negative rates from estrogen and progesterone receptor tests in local laboratories were 8.7% and 14.4%, respectively. The false positive rates from estrogen and progesterone receptor tests in local laboratories were 15.5% and 16.0%, respectively.

CONCLUSION

Technical and result interpretation issues may explain most of the discordances in hormone receptor testing in local laboratories. Validation of estrogen and progesterone receptor tests at local laboratories, with rigorous quality control measures, is strongly recommended in order to avoid erroneous treatment of breast cancer patients.

CG0006, a novel histone deacetylase inhibitor, induces breast cancer cell death via histone-acetylation and chaperone-disrupting pathways independent of ER status

We previously reported that CG0006, a novel hydroxamate-based pan-histone deacetylase inhibitor (HDACI), suppresses the growth of human cancer cells. Here, we tested the ability of CG0006 to inhibit breast cancer cell proliferation in relation to estrogen receptor (ER) status, and examined changes in the expression of cell-cycle regulatory proteins. CG0006 effects on the proliferation of multiple human cancer cell lines were tested using MTT and MTS assays. Changes in estrogen-signaling proteins and cell-cycle regulatory proteins were examined by western blotting and quantitative RT-PCR, and cell-cycle effects were tested using flow cytometry. CG0006 increased histone H3 and H4 acetylation, up-regulated p21 protein, and promoted cell-cycle arrest, inducing G(2)/M-phase accumulation in ER-positive MCF7 cells, and G(1)- and G(2)/M-phase accumulation in ER-negative MDA-MB-231 cells. In both cell types, CG0006 treatment (1 μM) reduced the levels of the estrogen-signaling proteins ERα and cyclin D1, and promoted massive degradation of cell-cycle regulatory proteins. CG0006 down-regulated the histone deacetylase HDAC6 at the protein level in association with a subsequent increase in Hsp90 and α-tubulin acetylation. HDAC6 depletion using small interfering RNA produced a protein-degradation phenotype similar to that of CG0006 treatment. These findings suggest that CG0006 inhibits breast cancer cell growth by two different pathways: a histone acetylation-dependent pathway, and a non-epigenetic pathway that disrupts chaperone function.

Minimising immunohistochemical false negative ER classification using a complementary 23 gene expression signature of ER status

BACKGROUND

Expression of the oestrogen receptor (ER) in breast cancer predicts benefit from endocrine therapy. Minimising the frequency of false negative ER status classification is essential to identify all patients with ER positive breast cancers who should be offered endocrine therapies in order to improve clinical outcome. In routine oncological practice ER status is determined by semi-quantitative methods such as immunohistochemistry (IHC) or other immunoassays in which the ER expression level is compared to an empirical threshold. The clinical relevance of gene expression-based ER subtypes as compared to IHC-based determination has not been systematically evaluated. Here we attempt to reduce the frequency of false negative ER status classification using two gene expression approaches and compare these methods to IHC based ER status in terms of predictive and prognostic concordance with clinical outcome.

METHODOLOGY/PRINCIPAL FINDINGS

Firstly, ER status was discriminated by fitting the bimodal expression of ESR1 to a mixed Gaussian model. The discriminative power of ESR1 suggested bimodal expression as an efficient way to stratify breast cancer; therefore we identified a set of genes whose expression was both strongly bimodal, mimicking ESR expression status, and highly expressed in breast epithelial cell lines, to derive a 23-gene ER expression signature-based classifier. We assessed our classifiers in seven published breast cancer cohorts by comparing the gene expression-based ER status to IHC-based ER status as a predictor of clinical outcome in both untreated and tamoxifen treated cohorts. In untreated breast cancer cohorts, the 23 gene signature-based ER status provided significantly improved prognostic power compared to IHC-based ER status (P = 0.006). In tamoxifen-treated cohorts, the 23 gene ER expression signature predicted clinical outcome (HR = 2.20, P = 0.00035). These complementary ER signature-based strategies estimated that between 15.1% and 21.8% patients of IHC-based negative ER status would be classified with ER positive breast cancer.

CONCLUSION/SIGNIFICANCE

Expression-based ER status classification may complement IHC to minimise false negative ER status classification and optimise patient stratification for endocrine therapies.