Can molecular markers predict when to implement treatment with aromatase inhibitors in invasive breast cancer?

Inactivation of FBXW7/hCDC4-β expression by promoter hypermethylation is associated with favorable prognosis in primary breast cancer

INTRODUCTION

Mutational inactivation of the FBXW7/hCDC4 tumor suppressor gene (TSG) is common in many cancer types, but infrequent in breast cancers. This study investigates the presence and impact of FBXW7/hCDC4 promoter methylation in breast cancer.

METHODS

FBXW7/hCDC4-β expression and promoter methylation was assessed in 161 tumors from two independent breast cancer cohorts. Associations between methylation status and clinicopathologic characteristics were assessed by Fisher's exact test. Survival was analyzed using the Kaplan-Meier method in addition to modeling the risk by use of a multivariate proportional hazard (Cox) model adjusting for possible confounders of survival.

RESULTS

Methylation of the promoter and loss of mRNA expression was found both in cell lines and primary tumors (43% and 51%, respectively). Using Cox modeling, a trend was found towards decreased hazard ratio (HR) for death in women with methylation of FBXW7/hCDC4-β in both cohorts (HR 0.53 (95% CI 0.23 to 1.23) and HR 0.50 (95% CI 0.23 to 1.08), respectively), despite an association between methylation and high-grade tumors (P = 0.017). Interestingly, in subgroups of patients whose tumors are p53 mutated or lymph-node positive, promoter methylation identified patients with significantly improved survival (P = 0.048 and P = 0.017, respectively).

CONCLUSIONS

We demonstrate an alternative mechanism for inactivation of the TSG FBXW7/hCDC4, namely promoter specific methylation. Importantly, in breast cancer, methylation of FBXW7/hCDC4-β is related to favorable prognosis despite its association with poorly differentiated tumors. Future work may define whether FBXW7/hCDC4 methylation is a biomarker of the response to chemotherapy and a target for epigenetic modulation therapy.

Is there an association with phosphorylation and dephosphorylation of Src kinase at tyrosine 530 and breast cancer patient disease-specific survival

BACKGROUND

recent work has demonstrated that c-Src and fully activated Y419Src expression was associated with poor clinical outcome of breast cancer patients. It is unknown whether different activation stages of c-Src equally influence disease-specific survival of breast cancer patients.

METHODS

immunohistochemistry was performed on 165 resected breast cancers using antibodies to phosphorylated and dephosphorylated Src kinase tyrosine site 530. Expression was assessed using the weighted histoscore method.

RESULTS

majority of phosphorylated and dephosphorylated Y530Src expression was observed in the nucleus and cytoplasm. Only 3.6% of phosphorylated Y530Src (pY530Src) expression was detected in the membrane, compared with 53% with dephosphorylated Y530Src. Nuclear expression of pY530Src correlated negatively with oestrogen receptor (ER) status (χ(2) P<0.001), whereas cytoplasmic phosphorylated and dephosphorylated Y530Src expression correlated negatively with membrane c-Src expression (χ(2) P=0.008, χ(2) P<0.001). On univariate and multivariate analysis, no significant association was noticed between phosphorylated or dephosphorylated Y530Src expression and disease-specific survival at any cellular location.

CONCLUSION

ER-negative breast cancer patients were more likely to express pY530Src in the nucleus. Breast cancer patients with higher cytoplasmic expression of phosphorylated or dephosphorylated Y530Src were more likely not to express c-Src at the membrane. Phosphorylated and dephosphorylated Y530Src expression is not associated with survival of patients.

Breast cancer patients' clinical outcome measures are associated with Src kinase family member expression

Background:

This study determined mRNA expression levels for Src kinase family (SFK) members in breast tissue specimens and assessed protein expression levels of prominent SFK members in invasive breast cancer to establish associations with clinical outcome. Ki67 was investigated to determine association between SFK members and proliferation.

Methods:

The mRNA expression levels were assessed for eight SFK members by quantitative real-time PCR. Immunohistochemistry was performed for c-Src, Lyn, Lck and Ki67.

Results:

mRNA expression was quantified in all tissue samples. SRC and LYN were the most highly expressed in malignant tissue. LCK was more highly expressed in oestrogen receptor (ER)-negative, compared with ER-positive tumours. High cytoplasmic Src kinase protein expression was significantly associated with decreased disease-specific survival. Lyn was not associated with survival at any cellular location. High membrane Lck expression was significantly associated with improved survival. Ki67 expression correlated with tumour grade and nuclear c-Src, but was not associated with survival.

Conclusions:

All eight SFK members were expressed in different breast tissues. Src kinase was highest expressed in breast cancer and had a negative impact on disease-specific survival. Membrane expression of Lck was associated with improved clinical outcome. High expression of Src kinase correlated with high proliferation.

Type I receptor tyrosine kinases as predictive or prognostic markers in early breast cancer

The type I receptor tyrosine kinase (RTK) family of proteins play an essential role in the progression of early breast cancer. Our understanding of the role of these proteins has increased over the last 20 years, however, as yet, there are still a number of unanswered questions regarding their position in endocrine resistance, chemotherapy resistance and in the biology of breast cancer. There have been, and are currently, a number of clinical trials that have examined the use of anticancer therapy such as cytotoxic drugs, and treatments that target the RTKs and signaling pathways that have been identified. There is clear evidence that molecular subtypes of cancer respond differently to different therapeutic options, which challenges the 'one size fits all' approach to chemotherapy. Here we review the human epidermal growth factor receptor family of proteins and their potential predictive or prognostic role in early breast cancer.

Sphingosine kinase 1 induces tolerance to human epidermal growth factor receptor 2 and prevents formation of a migratory phenotype in response to sphingosine 1-phosphate in estrogen receptor-positive breast cancer cells

We demonstrate here a new concept termed "oncogene tolerance" whereby human EGF receptor 2 (HER2) increases sphingosine kinase 1 (SK1) expression in estrogen receptor-positive (ER(+)) MCF-7 HER2 cells and SK1, in turn, limits HER2 expression in a negative-feedback manner. The HER2-dependent increase in SK1 expression also limits p21-activated protein kinase 1 (p65 PAK1) and extracellular signal regulated kinase 1/2 (ERK-1/2) signaling. Sphingosine 1-phosphate signaling via S1P(3) is also altered in MCF-7 HER2 cells. In this regard, S1P binding to S1P(3) induces a migratory phenotype via an SK1-dependent mechanism in ER(+) MCF-7 Neo cells, which lack HER2. This involves the S1P stimulated accumulation of phosphorylated ERK-1/2 and actin into membrane ruffles/lamellipodia and migration. In contrast, S1P failed to promote redistribution of phosphorylated ERK-1/2 and actin into membrane ruffles/lamellipodia or migration of MCF-7 HER2 cells. However, a migratory phenotype in these cells could be induced in response to S1P when SK1 expression had been knocked down with a specific siRNA or when recombinant PAK1 was ectopically overexpressed. Thus, the HER2-dependent increase in SK1 expression functions to desensitize the S1P-induced formation of a migratory phenotype. This is correlated with improved prognosis in patients who have a low HER1-3/SK1 expression ratio in their ER(+) breast cancer tumors compared to patients that have a high HER1-3/SK1 expression ratio.

Tamoxifen resistance in early breast cancer: statistical modelling of tissue markers to improve risk prediction

BACKGROUND

For over two decades, the Nottingham Prognostic Index (NPI) has been used in the United Kingdom to calculate risk scores and inform management about breast cancer patients. It is derived using just three clinical variables - nodal involvement, tumour size and grade. New scientific methods now make cost-effective measurement of many biological characteristics of tumour tissue from breast cancer biopsy samples possible. However, the number of potential explanatory variables to be considered presents a statistical challenge. The aim of this study was to investigate whether in ER+ tamoxifen-treated breast cancer patients, biological variables can add value to NPI predictors, to provide improved prognostic stratification in terms of overall recurrence-free survival (RFS) and also in terms of remaining recurrence free while on tamoxifen treatment (RFoT). A particular goal was to enable the discrimination of patients with a very low risk of recurrence.

METHODS

Tissue samples of 401 cases were analysed by microarray technology, providing biomarker data for 72 variables in total, from AKT, BAD, HER, MTOR, PgR, MAPK and RAS families. Only biomarkers screened as potentially informative (i.e., exhibiting univariate association with recurrence) were offered to the multivariate model. The multiple imputation method was used to deal with missing values, and bootstrap sampling was used to assess internal validity and refine the model.

RESULTS

Neither the RFS nor RFoT models derived included Grade, but both had better predictive and discrimination ability than NPI. A slight difference was observed between models in terms of biomarkers included, and, in particular, the RFoT model alone included HER2. The estimated 7-year RFS rates in the lowest-risk groups by RFS and RFoT models were 95 and 97%, respectively, whereas the corresponding rate for the lowest-risk group of NPI was 89%.

CONCLUSION

The findings demonstrate considerable potential for improved prognostic modelling by incorporation of biological variables into risk prediction. In particular, the ability to identify a low-risk group with minimal risk of recurrence is likely to have clinical appeal. With larger data sets and longer follow-up, this modelling approach has the potential to enhance an understanding of the interplay of biological characteristics, treatment and cancer recurrence.

Predictive markers of anthracycline benefit: a prospectively planned analysis of the UK National Epirubicin Adjuvant Trial (NEAT/BR9601)

BACKGROUND

The NEAT/BR9601 trial showed benefit for addition of anthracyclines to cyclophosphamide, methotrexate, and fluorouracil (CMF) as adjuvant treatment for early breast cancer. We investigated prospectively predictive biomarkers of anthracycline benefit including HER2 and TOP2A.

METHODS

1941 tumours from 2391 women recruited to NEAT/BR9601 were analysed on tissue microarrays for HER2 and TOP2A amplification and deletion, HER1-3 and Ki67 expression, and duplication of chromosome 17 centromere enumeration probe (Ch17CEP). Log-rank analyses identified factors affecting relapse-free and overall survival, and regression models tested independent prognostic effect of markers, with adjustment for known prognostic factors (age, nodal status, oestrogen-receptor status, grade, and tumour size). The predictive value of markers was tested by treatment interactions for relapse-free and overall survival.

FINDINGS

1762 patients were analysed. 21% of tumours (n=367) were HER2 amplified, 10% were TOP2A amplified (n=169), 11% showed TOP2A deleted (n=191), 23% showed Ch17CEP duplication (n=406), and 61% had high (>13.0%) Ki67 (n=1136). In univariate analyses, only HER2 amplification and TOP2A deletion were significant prognostic factors for relapse-free (hazard ratio [HR] 1.59, 95% CI 1.32-1.92, p<0.0001; and 1.52, 1.20-1.92, p=0.0006, respectively) and overall survival (1.79, 1.47-2.19, p<0.0001; and 1.62, 1.26-2.08, p=0.0002 respectively). We detected no significant interaction with anthracycline benefit for Ki67, HER2, HER1-3, or TOP2A. By contrast, in multivariate analyses, Ch17CEP duplication was associated with significant improvements in both relapse-free (HR 0.92, 95% CI 0.72-1.18 for tumours with normal Ch17CEP vs 0.52, 0.34-0.81 for tumours with abnormal Ch17CEP; p for interaction=0.004) and overall survival (0.94, 0.72-1.24 vs 0.57, 0.36-0.92; p for interaction=0.02) with anthracycline use.

INTERPRETATION

In women with early breast cancer receiving adjuvant chemotherapy, the most powerful predictor of benefit from anthracyclines is Ch17CEP duplication. In view of the location of HER2/TOP2A on chromosome 17, Ch17CEP duplication might explain the inconsistencies in previous studies of factors predicting benefit from anthracyclines.

FUNDING

Cancer Research UK and the Scottish Breast Cancer Clinical Trials Group.

Informatics, evidence-based care, and research; implications for national policy: a report of an American Medical Informatics Association health policy conference

There is an increased level of activity in the biomedical and health informatics world (e-prescribing, electronic health records, personal health records) that, in the near future, will yield a wealth of available data that we can exploit meaningfully to strengthen knowledge building and evidence creation, and ultimately improve clinical and preventive care. The American Medical Informatics Association (AMIA) 2008 Health Policy Conference was convened to focus and propel discussions about informatics-enabled evidence-based care, clinical research, and knowledge management. Conference participants explored the potential of informatics tools and technologies to improve the evidence base on which providers and patients can draw to diagnose and treat health problems. The paper presents a model of an evidence continuum that is dynamic, collaborative, and powered by health informatics technologies. The conference's findings are described, and recommendations on terminology harmonization, facilitation of the evidence continuum in a "wired" world, development and dissemination of clinical practice guidelines and other knowledge support strategies, and the role of diverse stakeholders in the generation and adoption of evidence are presented.

Combinatorial biomarker expression in breast cancer

Current clinical management of breast cancer relies on the availability of robust clinicopathological variables and few well-defined biological markers. Recent microarray-based expression profiling studies have emphasised the importance of the molecular portraits of breast cancer and the possibility of classifying breast cancer into biologically and molecularly distinct groups. Subsequent large scale immunohistochemical studies have demonstrated that the added value of studying the molecular biomarker expression in combination rather than individually. Oestrogen (ER) and progesterone (PR) receptors and HER2 are currently used in routine pathological assessment of breast cancer. Additional biomarkers such as proliferation markers and 'basal' markers are likely to be included in the future. A better understanding of the prognostic and predictive value of combinatorial assessment of biomarker expression could lead to improved breast cancer management in routine clinical practice and would add to our knowledge concerning the variation in behaviour and response to therapy. Here, we review the evidence on the value of assessing biomarker expression in breast cancer individually and in combination and its relation to the recent molecular classification of breast cancer.

Endocrine resistance associated with activated ErbB system in breast cancer cells is reversed by inhibiting MAPK or PI3K/Akt signaling pathways

Endocrine therapy resistance is one of the main challenges in the treatment of estrogen receptor positive (ER+) breast cancer patients. This study showed that two ER+ human breast carcinoma cell lines derived from MCF-7 (MVLN cells) that have acquired under OH-Tamoxifen selection two distinct phenotypes of endocrine resistance both displayed constitutive activation of the PI3K/Akt and MAPK pathways. Aberrant expression and activation of the ErbB system (phospho-EGFR, phospho-ErbB2, phospho-ErbB3, over-expression of ErbB4 and over-expression of several ErbB ligands) were also observed in the two resistant cell lines, suggesting the existence of an autocrine loop leading to constitutive activation of MAPK and PI3K/Akt survival pathways. The recent clinical use of specific signal transduction inhibitors is one of the most promising therapeutic approaches in breast cancers. The MEK inhibitor PD98059 and the PI3K inhibitor LY294002 were both able to enhance the cytostatic effect of OH-Tamoxifen or fulvestrant on MVLN sensitive cells. In the two resistant cell lines, inhibition of the MAPK or the PI3K/Akt pathways associated with endocrine therapy was sufficient to reverse OH-Tamoxifen or fulvestrant resistance. Investigating the effect of a combination of both inhibitors on the reversion of OH-Tamoxifen and fulvestrant resistance in the two resistant cell lines suggested that, in clinical practice, a strategy combining the two inhibitors would be the best approach to target the different endocrine resistance phenotypes possibly present in a tumor. In conclusion, the combination of MAPK and PI3K inhibitors represents a promising strategy to overcome endocrine therapy resistance in ER+ breast cancer patients.

Early and late tamoxifen resistance in breast cancer

In our study we investigated the role of the estrogen receptor (ER), progesterone receptor (PR) and clinicohistological parameters in breast cancer patients treated with tamoxifen during the early (2.5 years) vs. late (2.5-5 years) follow-up. The negative status of both ER and PR and tumors equal to or bigger than 2 cm defined the phenotypes and consequently the groups of patients with the worst clinical course of the disease: ER-negative PR-negative, ER-negative pT2 and PR-negative pT2. These high-risk subgroups were related to early follow-up indicating de novo resistance. It is relevant to point out that examined predictive indicators did not show significant importance in the late follow-up study.

Is expression or activation of Src kinase associated with cancer-specific survival in ER-, PR- and HER2-negative breast cancer patients?

The aim of the current study was to assess the expression levels of c-Src and phosphorylated Src kinase in human breast cancers and to establish if these are linked to oestrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 status or patient survival. Tissue microarray technology was used to analyze 314 breast cancer specimens. Immunohistochemistry was performed using antibodies to c-Src, Y419Src, and Y215Src, and expression was assessed using the weighted histoscore method. High cytoplasmic c-Src kinase and high membrane phosphorylated activated Y419Src kinase was associated with decreased disease-specific survival. In contrast, phosphorylated activated nuclear and cytoplasmic Y215Src kinase expression levels were significantly associated with improved disease-specific survival. When the cohort was subdivided according to ER/PR/HER2 status, the ER-negative subgroup (105 patients) was associated with improved disease-specific survival and was found to be independent by multivariate analysis with a hazard ratio of 0.4 (interquartile range 0.2-0.8). High cytoplasmic c-Src expression was associated with decreased survival; high expression of activated c-Src (Y215) was associated with improved survival. This was potentiated in the ER/HER2-negative subgroup. Hence, administration of Src kinase inhibitors aiming to decrease phosphorylation should be approached with caution, especially in ER-negative patients. It is therefore essential to appropriately identify with the correct biomarkers which patients are most likely to respond to Src inhibitors.

Overexpression of PTK6 (breast tumor kinase) protein--a prognostic factor for long-term breast cancer survival--is not due to gene amplification

In a previous retrospective study, we demonstrated the prognostic value of protein tyrosine kinase 6 (PTK6) protein expression in breast carcinomas. Here, we analyzed PTK6 gene amplification using fluorescence in situ hybridization technique in a cohort of 426 invasive breast carcinomas and compared it with PTK6 expression level as well as with the clinical outcome of patients. Forty-five percent of tumors show increased PTK6 gene copy numbers when compared to normal tissue. Most of these, however, were related to chromosome 20 polysomy (30%), while gene amplification accounted for only 15%. Only "low level" amplification of the PTK6 gene, with up to eight signals per nucleus, was found. The PTK6 cytogenetic status (normal, gene amplification, polysomy 20) was not associated with histopathological parameters or with the protein expression of HER receptors. No statistical association was identified between PTK6 gene status and expression level. Further, the PTK6 gene status does not influence the disease-free survival of patients at > or = 240 months. Based on these results, we state that the PTK6 overexpression is not essentially attributed to gene amplification, and the PTK6 protein expression-but not gene status-is of prognostic value in breast carcinomas. PTK6 protein overexpression may result from polysomy 20 in a minority of the tumors. In a marked proportion of tumors, however, the overexpression is likely to be caused by posttranscriptional regulation mechanisms.

The HER-2 receptor and breast cancer: ten years of targeted anti-HER-2 therapy and personalized medicine

The human epidermal growth factor receptor (HER-2) oncogene encodes a transmembrane tyrosine kinase receptor that has evolved as a major classifier of invasive breast cancer and target of therapy for the disease. The validation of the general prognostic significance of HER-2 gene amplification and protein overexpression in the absence of anti-HER-2 targeted therapy is discussed in a study of 107 published studies involving 39,730 patients, which produced an overall HER-2-positive rate of 22.2% and a mean relative risk for overall survival (OS) of 2.74. The issue of HER-2 status in primary versus metastatic breast cancer is considered along with a section on the features of metastatic HER-2-positive disease. The major marketed slide-based HER-2 testing approaches, immunohistochemistry, fluorescence in situ hybridization, and chromogenic in situ hybridization, are presented and contrasted in detail against the background of the published American Society of Clinical Oncology-College of American Pathologists guidelines for HER-2 testing. Testing issues, such as the impact of chromosome 17 polysomy and local versus central HER-2 testing, are also discussed. Emerging novel HER-2 testing techniques, including mRNA-based testing by real-time polymerase chain reaction and DNA microarray methods, HER-2 receptor dimerization, phosphorylated HER-2 receptors, and HER-2 status in circulating tumor cells, are also considered. A series of biomarkers potentially associated with resistance to trastuzumab is discussed with emphasis on the phosphatase and tensin homologue deleted on chromosome ten/Akt and insulin-like growth factor receptor pathways. The efficacy results for the more recently approved small molecule HER-1/HER-2 kinase inhibitor lapatinib are also presented along with a more limited review of markers of resistance for this agent. Additional topics in this section include combinations of both anti-HER-2 targeted therapies together as well as with novel agents including bevacizumab, everolimus, and tenespimycin. A series of novel HER-2-targeting agents is also presented, including pertuzumab, ertumaxomab, HER-2 vaccines, and recently discovered tyrosine kinase inhibitors. Biomarkers predictive of HER-2 targeted therapy toxicity are included, and the review concludes with a consideration of HER-2 status in the prediction of response to non-HER-2 targeted treatments including hormonal therapy, anthracyclines, and taxanes.

Review of the ATAC study: tamoxifen versus anastrozole in early-stage breast cancer

A 5-year regimen of tamoxifen hormone therapy has historically been the recommendation for hormone receptor-positive, postmenopausal women with early-stage breast cancer. With the advent of aromatase inhibitors, there has been extensive work carried out to investigate the role of these agents in the adjuvant setting. Studies have been designed to answer whether these agents should be used upfront (instead of tamoxifen) or in conjunction (either in a switch or extended program). The Arimidex, Tamoxifen Alone or in Combination (ATAC) trial is a landmark trial that demonstrated the superiority of upfront anastrozole over tamoxifen. This article reviews the trial and discusses both the optimum timing of initiation of aromatase inhibitors and the future approach of more individualized therapy, with the detection of predictive markers.

Determination of HER2 phosphorylation at tyrosine 1221/1222 improves prediction of poor survival for breast cancer patients with hormone receptor-positive tumors

INTRODUCTION

High expression of total HER2 protein confers poor prognosis for breast cancer patients. HER2 is a member of the HER family consisting of four receptors, HER1 to HER4. HER receptor activity is regulated by a variety of mechanisms, and phosphorylation of the C-terminal part of the HER receptors is a marker for active signaling. The importance of phosphorylation and thereby activation of the HER1 to HER4 receptors, however, has not been investigated concomitantly in breast tumors. In the present study we examined the importance of active HER signaling in breast tumor biopsies and paired metastases, by evaluating the expression of phosphorylated HER1, HER2, HER3, Erk, Akt and the total level of HER4 and HER2.

METHODS

Immunohistochemical analysis was performed on 268 primary breast tumors and 30 paired metastatic lesions from postmenopausal women with hormone receptor-positive breast tumors, who had received adjuvant tamoxifen therapy. The observed protein expression levels were analyzed for co-expression, for correlation to clinicopathological parameters and for prognostic value in relation to disease-free survival and overall survival. Lastly, the difference between protein levels in primary tumors versus metastasis was evaluated.

RESULTS

In the primary tumors, 8%, 18%, 14% and 15% of cases were scored positive for total HER2, pHER1, pHER2 and pHER3 expression, respectively. HER4 was expressed with strong intensity in 68% and at moderate intensity in 29% of cases. The activated forms of Akt and Erk were quite uniformly expressed in the categories; negative, moderate or strong. In univariate analysis, expression of total HER2, pHER1, pHER2 and pHER3 was significantly associated with poor disease-free survival. Strong HER4 expression was associated with prolonged disease-free as well as with overall survival. Expression of pAkt and pErk was not correlated with survival. In multivariate analysis, pHER2 expression was clearly an independent marker for poor disease-free survival and overall survival when tested against tumor size, tumor grade, nodal status and HER2. Lastly, comparison of HER receptor expression in metastatic versus primary tumors showed a significant increase in expression of pHER1 and pHER3 in the metastases.

CONCLUSIONS

In hormone receptor-positive breast cancer, determination of pHER2 yields additional prognostic information about poor prognosis compared with the current clinical standard for measuring HER2.

Progesterone receptor is a significant factor associated with clinical outcomes and effect of adjuvant tamoxifen therapy in breast cancer patients

Estrogen receptor status in breast cancer is associated with response to hormonal therapy and clinical outcome. The additional value of progesterone receptor (PR) has remained controversial. We examine the value of PR for prognosis and response to tamoxifen on a population-based series of 4,046 invasive early stage breast cancer patients. Clinical information for age at diagnosis, stage, pathology, treatment and outcome was assembled for the study cohort; the median follow-up was 12.4 years. PR status was determined by immunohistochemistry using a rabbit monoclonal antibody on tissue microarrays built from breast tumor surgical excisions. Survival analyses, Kaplan-Meier functions and Cox proportional hazards regression models were applied to assess the associations between PR and breast cancer specific survival. Progesterone receptor was positive in 51% of all cases and 67% of estrogen receptor positive (ER+) cases. Survival analyses for both the whole cohort and ER+ cases given tamoxifen therapy showed that patients with PR+ tumors had 24% higher relative probability for breast cancer specific survival as compared to PR- patients, adjusted for ER, HER2, age at diagnosis, grade, tumor size, lymph node status and lymphovascular invasion covariates. Higher PR expression showed stronger association with patient survival. Log-likelihood ratio tests of multivariate Cox proportional hazards regression models demonstrated that PR was an independent statistically significant factor for breast cancer specific survival in both the whole cohort and among ER+ cases treated with tamoxifen. PR adds significant prognostic value in breast cancer beyond that obtained with estrogen receptor alone.

Phosphorylated c-Src in the nucleus is associated with improved patient outcome in ER-positive breast cancer

Elevated c-Src protein expression has been shown in breast cancer and in vitro evidence suggests a role in endocrine resistance. To investigate whether c-Src is involved in endocrine resistance, we examined the expression of both total and activated c-Src in human breast cancer specimens from a cohort of oestrogen receptor (ER)-positive tamoxifen-treated breast cancer patients. Tissue microarray technology was employed to analyse 262 tumour specimens taken before tamoxifen treatment. Immunohistochemistry using total c-Src and activated c-Src antibodies was performed. Kaplan–Meier survival curves were constructed and log-rank test were performed. High level of nuclear activated Src was significantly associated with improved overall survival (P=0.047) and lower recurrence rates on tamoxifen (P=0.02). Improved patient outcome was only seen with activated Src in the nucleus. Nuclear activated Src expression was significantly associated with node-negative disease and a lower NPI (P<0.05). On subgroup analysis, only ER-positive/progesterone receptor (PgR)-positive tumours were associated with improved survival (P=0.004). This shows that c-Src activity is increased in breast cancer and that activated Src within the nucleus of ER-positive tumours predicts an improved outcome. In ER/PgR-positive disease, activated Src kinase does not appear to be involved in de novo endocrine resistance. Further study is required in ER-negative breast cancer as this may represent a cohort in which it is associated with poor outcome.

Type 1 Receptor Tyrosine Kinase Profiles Identify Patients With Enhanced Benefit From Anthracyclines in the BR9601 Adjuvant Breast Cancer Chemotherapy Trial

Purpose

Patients with early breast cancer who receive anthracycline-containing chemotherapy experience improved relapse-free (RFS) and overall survival (OS) compared with those who receive non–anthracycline-containing chemotherapy. Such benefit, however, may be restricted to women whose tumors have specific molecular characteristics. We tested the hypothesis that HER2, epidermal growth factor receptor (EGFr)/HER1, HER3, Ki67, and topoisomerase IIα expression are predictive of outcome after anthracycline-based chemotherapy.

Methods

Tissue microarrays from 322 of 374 women in the BR9601 trial, which compared cyclophosphamide, methotrexate, and fluorouracil (CMF) with epirubicin followed by CMF (epi-CMF), were analyzed for HER1, 2, 3, 4; Ki67; and topoisomerase IIα protein expression and for HER2/topoisomerase IIα gene amplification. Their relationships to RFS and OS were investigated, and multiple regression analysis was used to identify interactions.

Results

A significant interaction was seen between tumors with normal HER1, HER2 fluorescent in situ hybridization (FISH), or HER3 levels and the enhanced benefit from epi-CMF versus CMF for RFS (hazard ratio [HR], 0.36; HR for overexpressed HER1 or HER2 FISH or HER3, 0.92; P = .035) and for OS (HR, 0.30; HR for overexpressed HER1 or HER2 FISH or HER3), 0.98; P = .023). Neither Ki67 nor TIIα expressions or gene alterations showed clear predictive value for benefit from the addition of the anthracycline.

Conclusion

Patients with HER2 amplified and those with HER1, HER2 FISH, or HER3-positive tumors did not benefit from the addition of epirubicin to CMF. Conversely, patients with HER2 nonamplified and HER1 through HER3–negative tumors showed significantly increased RFS and OS rates when treated with epi-CMF compared with CMF.

Microarray methods to identify factors determining breast cancer progression: potentials, limitations, and challenges

65-80% of the patients with breast cancer might not benefit from the adjuvant therapy they receive based on 'classical' markers used for the selection for adjuvant therapy. Therefore it is necessary to develop new markers that are able to tailor treatment for an individual patient. A number of microarray methods have been developed in recent years to accommodate this search for new factors that determine breast cancer progression. We give an overview of the most commonly used microarray methods to identify tumour progression markers (oligo- or cDNA arrays, CGH arrays, PCR arrays, and tissue microarrays). Their applications will be illustrated using the most influential examples from literature. The potentials, limitations and the related statistical analyses of each method are discussed. We conclude that microarray studies have led to an increase in the understanding of the complexity and diversity of breast carcinoma and have provided clinical relevant subgroups of breast cancer that may benefit from patient tailored treatment. Still, more extensive external validation and long-term follow-up will be necessary before such assays can be implemented into routine clinical practice. Most likely, these novel prognostic indicators will be complementary to the already available classical prognostic factors.

Prognostic value of protein tyrosine kinase 6 (PTK6) for long-term survival of breast cancer patients

The cytoplasmic tyrosine kinase PTK6 (BRK) shows elevated expression in approximately two-thirds of primary breast tumours, and is implicated in EGF receptor-dependent signalling and epithelial tumorigenesis. Using immunohistochemistry, we performed a retrospective study on 426 archival breast cancer samples from patients with long-term follow-up and compared the protein expression levels of PTK6, the HER receptors, Sam68 (a substrate of PTK6), and signalling proteins including MAP kinase (MAPK), phosphorylated MAPK (P-MAPK), and PTEN. We show that PTK6 expression is of significant prognostic value in the outcome of breast carcinomas. In multivariate analysis, the disease-free survival of patients of >or=240 months was directly associated with the protein expression level of PTK6 (P<or=0.001), but was also inversely associated with nodal status (P<or=0.001) and tumour size (P<or=0.01). PTK6 expression in tumour tissue significantly correlated (P<or=0.05) with the expression of PTEN, MAPK, P-MAPK, and Sam68. To investigate whether these correlations may be due to molecular interactions between PTK6 and these proteins, we used protein extracts from the T47D cell line for immunoprecipitation and western blot analysis. By this, interactions could be demonstrated between PTK6 and MAPK, P-MAPK, HER2/neu, HER3, HER4, PTEN, and Sam68. On the basis of these results, we suggest that PTK6 may serve as a future target for the development of novel treatments in breast cancer.

The epidermal growth factor receptor family in breast cancer

THE HUMAN EPIDERMAL GROWTH FACTOR RECEPTOR (HER) FAMILY COMPRISES FOUR HOMOLOGOUS MEMBERS: EGFR, HER-2, HER-3, and HER-4. The activation of these receptors triggers a complex series of signal transduction pathways which affect pivotal tumorigenic processes. The deregulation of HER signaling is seen in several human malignancies. HER-2 is now recognized as a key oncogene in breast cancer pathogenesis. Assessment of HER-2 status is of central importance in the prognosis of breast cancer patients. In the light of clinical data suggesting that HER-2 can also be useful as a predictive marker both for trastuzumab and chemotherapy, standardized determination of the HER-2 status in tumors has become more important. Moreover, current data provide evidence for the significance of HER-3 and HER-4 alterations in breast carcinogenesis. Because of the complex interactions among the HER receptors, it is likely that the effect on cell proliferation and tumor growth depends on receptor trans-signaling and thus, the evaluation of the combined expression pattern of all family members is of particular interest. This review presents the current evidence highlighting the role of the family as a whole panel and an update on the role of HER-3 and HER-4 receptors in breast cancer. Moreover, we provide updated data regarding the prognostic value of HER family members giving emphasis to novel methods for the determination of their status, such as real-time polymerase chain reaction. In addition, we review recent therapeutic approaches aimed at targeting the HER family in breast cancer patients.

The role of ErbB3 and its binding partners in breast cancer progression and resistance to hormone and tyrosine kinase directed therapies

An increasingly important role for the ErbB3 receptor in the genesis and progression of breast cancer is emerging. ErbB3 is frequently overexpressed in breast cancer and coexpression of ErbB2/3 is a poor prognostic indicator. ErbB3 has also been implicated in the development of resistance to antiestrogens such as tamoxifen and ErbB tyrosine kinase inhibitors such as gefitinib. Persistent activation of the AKT pathway has been postulated to contribute to ErbB3-mediated resistance to these therapies. This activation may be due in part to the inappropriate production of the ErbB3 ligand heregulin. ErbB3 binding proteins, which negatively regulate ErbB3 protein levels and the ability of ErbB3 to transmit proliferative signals, also contribute to breast cancer progression and treatment resistance. These proteins include the intracellular RING finger E3 ubiquitin ligase Nrdp1 and the leucine-rich protein LRIG-1 that mediate receptor degradation. Ebp1, another ErbB3 binding protein, suppresses HRG driven breast cancer cell growth and contributes to tamoxifen sensitivity. These studies point to the importance of the evaluation of protein levels and functional activity of ErbB3 and its binding proteins in breast cancer prognosis and prediction of clinical response to treatment.

Molecular profiles of progesterone receptor loss in human breast tumors

BACKGROUND

Patient prognosis and response to endocrine therapy in breast cancer correlate with protein expression of both estrogen receptor (ER) and progesterone receptor (PR), with poorer outcome in patients with ER+/PR- compared to ER+/PR+ tumors.

METHODS

To better understand the underlying biology of ER+/PR- tumors, we examined RNA expression (n > 1000 tumors) and DNA copy number profiles from five previously published studies of human breast cancers with clinically assigned hormone receptor status (ER+/PR+, ER+/PR-, and ER-/PR-).

RESULTS

We identified an expression "signature" of genes with either elevated or diminished RNA levels specifically in ER+/PR+ compared to ER-/PR- and ER+/PR- tumors. We similarly identified a gene signature specific to ER-/PR- tumors. ER+/PR- tumors, on the other hand, were a mixture of three different subtypes: tumors manifesting the ER+/PR+ signature, tumors manifesting the ER-/PR- signature, and tumors not associating with ER+/PR+ or ER-/PR- tumors (which we considered "true" ER+/PR-). In analyses of both tamoxifen-treated and untreated patients, ER+/PR- breast cancers defined by RNA profiling were associated with poor patient outcome, worse than those with pure ER+/PR+ patterns; these differences were not observed when using clinical assays to assign ER and PR status. ER+/PR- tumors also showed twice as many DNA copy number gains or losses compared to ER+/PR+ and ER-PR- tumors. Targets of transcriptional up-regulation by specific oncogenic pathways, including PI3 K/Akt/mTOR, were enriched in both ER+/PR- and ER-/PR- compared to ER+/PR+ tumors.

CONCLUSION

ER+/PR- tumors as defined by RNA profiling represent a distinct subset of breast cancer with aggressive features and poor outcome, despite being clinically ER+. Multigene assays derived from our gene signatures could conceivably provide an improved clinical assay for inferring PR status for prognostic and therapeutic purposes.

The ERBB3 receptor in cancer and cancer gene therapy

ERBB3, a member of the epidermal growth factor receptor (EGFR) family, is unique in that its tyrosine kinase domain is functionally defective. It is activated by neuregulins, by other ERBB and nonERBB receptors as well as by other kinases, and by novel mechanisms. Downstream it interacts prominently with the phosphoinositol 3-kinase/AKT survival/mitogenic pathway, but also with GRB, SHC, SRC, ABL, rasGAP, SYK and the transcription regulator EBP1. There are likely important but poorly understood roles for nuclear localization and for secreted isoforms. Studies of ERBB3 expression in primary cancers and of its mechanistic contributions in cultured cells have implicated it, with varying degrees of certainty, with causation or sustenance of cancers of the breast, ovary, prostate, certain brain cells, retina, melanocytes, colon, pancreas, stomach, oral cavity and lung. Recent results link high ERBB3 activity with escape from therapy targeting other ERBBs in lung and breast cancers. Thus a wide and centrally important role for ERBB3 in cancer is becoming increasingly apparent. Several approaches for targeting ERBB3 in cancers have been tested or proposed. Small inhibitory RNA (siRNA) to ERBB3 or AKT is showing promise as a therapeutic approach to treatment of lung adenocarcinoma.

Crosstalk between the estrogen receptor and the HER tyrosine kinase receptor family: molecular mechanism and clinical implications for endocrine therapy resistance

Breast cancer evolution and tumor progression are governed by the complex interactions between steroid receptor [estrogen receptor (ER) and progesterone receptor] and growth factor receptor signaling. In recent years, the field of cancer therapy has witnessed the emergence of multiple strategies targeting these specific cancer pathways and key molecules (ER and growth factor receptors) to arrest tumor growth and achieve tumor eradication; treatment success, however, has varied and both de novo (up front) and acquired resistance have proven a challenge. Recent studies of ER biology have revealed new insights into ER action in breast cancer and have highlighted the role of an intimate crosstalk between the ER and HER family signaling pathways as a fundamental contributor to the development of resistance to endocrine therapies against the ER pathway. The aim of this review article is to summarize the current knowledge on mechanisms of resistance of breast cancer cells to endocrine therapies due to the crosstalk between the ER and the HER growth factor receptor signaling pathways and to explore new available therapeutic strategies that could prolong duration of response and circumvent endocrine resistant tumor growth.

Tamoxifen resistance in breast tumors is driven by growth factor receptor signaling with repression of classic estrogen receptor genomic function

Not all breast cancers respond to tamoxifen, and many develop resistance despite initial benefit. We used an in vivo model of estrogen receptor (ER)-positive breast cancer (MCF-7 xenografts) to investigate mechanisms of this resistance and develop strategies to circumvent it. Epidermal growth factor receptor (EGFR) and HER2, which were barely detected in control estrogen-treated tumors, increased slightly with tamoxifen and were markedly increased when tumors became resistant. Gefitinib, which inhibits EGFR/HER2, improved the antitumor effect of tamoxifen and delayed acquired resistance, but had no effect on estrogen-stimulated growth. Phosphorylated levels of p42/44 and p38 mitogen-activated protein kinases (both downstream of EGFR/HER2) were increased in the tamoxifen-resistant tumors and were suppressed by gefitinib. There was no apparent increase in phosphorylated AKT (also downstream of EGFR/HER2) in resistant tumors, but it was nonetheless suppressed by gefitinib. Phosphorylated insulin-like growth factor-IR (IGF-IR), which can interact with both EGFR and membrane ER, was elevated in the tamoxifen-resistant tumors compared with the sensitive group. However, ER-regulated gene products, including total IGF-IR itself and progesterone receptor, remained suppressed even at the time of acquired resistance. Tamoxifen's antagonism of classic ER genomic function was retained in these resistant tumors and even in tumors that overexpress HER2 (MCF-7 HER2/18) and are de novo tamoxifen-resistant. In conclusion, EGFR/HER2 may mediate tamoxifen resistance in ER-positive breast cancer despite continued suppression of ER genomic function by tamoxifen. IGF-IR expression remains dependent on ER but is activated in the tamoxifen-resistant tumors. This study provides a rationale to combine HER inhibitors with tamoxifen in clinical studies, even in tumors that do not initially overexpress EGFR/HER2.

Relationship between quantitative estrogen and progesterone receptor expression and human epidermal growth factor receptor 2 (HER-2) status with recurrence in the Arimidex, Tamoxifen, Alone or in Combination trial

PURPOSE

To determine the relationship between quantitative estrogen-receptor (ER) and progesterone-receptor (PgR) expression and human epidermal growth factor 2 (HER-2) status with time to recurrence (TTR) in postmenopausal women with hormone receptor-positive primary breast cancer treated with anastrozole or tamoxifen as adjuvant therapy.

PATIENTS AND METHODS

Formalin-fixed, paraffin-embedded tumor blocks were retrospectively collected from patients in the monotherapy arms of the Arimidex, Tamoxifen Alone or in Combination (ATAC) trial and centrally tested for ER, PgR and HER-2. ER and PgR were scored using continuous scales and HER-2 was scored as 0 to 3+ with 2+ cases being analyzed by fluorescence in situ hybridization.

RESULTS

Blocks were collected from 2,006 of 5,880 eligible patients. Tissue was assessable and ER and/or PgR positivity confirmed centrally in 1,782 cases. In these, TTR was longer for anastrozole than for tamoxifen by a similar extent to that in the overall trial. None of the three biomarkers identified a set of patients with differential benefit from anastrozole over tamoxifen. Patients with low ER, low PgR, and high HER-2 expression had a poorer prognosis with either drug. Only 2.6% of patients in the highest quartile of PgR experienced recurrence after 5 years, compared with 13.2% in the lowest quartile.

CONCLUSION

Quantitative expression of ER and PgR and HER-2 status did not identify patients with differential relative benefit from anastrozole over tamoxifen: TTR was longer for anastrozole than for tamoxifen in all molecular subgroups. Low ER or PgR or high HER-2 expression are associated with a high risk of recurrence with either anastrozole or tamoxifen.

Cytogenetic analysis of HER1/EGFR, HER2, HER3 and HER4 in 278 breast cancer patients

INTRODUCTION

The HER (human EGFR related) family of receptor tyrosine kinases (HER1/EGFR (epidermal growth factor receptor)/c-erbB1, HER2/c-erbB2, HER3/c-erbB3 and HER4/c-erbB4) shares a high degree of structural and functional homology. It constitutes a complex network, coupling various extracellular ligands to intracellular signal transduction pathways resulting in receptor interaction and cross-activation. The most famous family member is HER2, which is a target in Herceptin therapy in metastatic status and also in adjuvant therapy of breast cancer in the event of dysregulation as a result of gene amplification and resulting protein overexpression. The HER2-related HER receptors have been shown to interact directly with HER2 receptors and thereby mutually affect their activity and subsequent malignant growth potential. However, the clinical outcome with regard to total HER receptor state remains largely unknown.

METHODS

We investigated HER1-HER4, at both the DNA and the protein level, using fluorescence in situ hybridisation (FISH) probes targeted to all four receptor loci and also immunohistochemistry in tissue microarrays derived from 278 breast cancer patients.

RESULTS

We retrospectively found HER3 gene amplification with a univariate negative impact on disease-free survival (hazard ratio 2.35, 95% confidence interval 1.08 to 5.11, p = 0.031), whereas HER4 amplification showed a positive trend in overall and disease-free survival. Protein expression revealed no additional information.

CONCLUSION

Overall, the simultaneous quantification of HER3 and HER4 receptor genes by means of FISH might enable the rendering of a more precise stratification of breast cancer patients by providing additional prognostic information. The continuation of explorative and prospective studies on all HER receptors will be required for an evaluation of their potential use for specific therapeutic targeting with respect to individualised therapy.

Human epidermal growth factor receptor 2 status correlates with lymph node involvement in patients with estrogen receptor (ER) negative, but with grade in those with ER-positive early-stage breast cancer suitable for cytotoxic chemotherapy

PURPOSE

Human epidermal growth factor receptor 2 (HER-2) expression is associated with increased risk of high-grade disease, nodal metastasis, and absence of estrogen receptors (ERs) in early breast cancer. We tested interactions between ER and HER-2 to determine if they may modulate breast cancer nodal metastasis and proliferation.

PATIENTS AND METHODS

Tumors from the Cancer Research UK Taxotere as Adjuvant Chemotherapy phase III trial were tested for HER-2 using current diagnostic procedures. ER status, progesterone status, clinicopathologic characteristics, and patient age were included in a logistic regression analysis to identify associations with HER-2 status (positive v negative).

RESULTS

A total of 841 (23.6%) of 3,565 samples were HER-2 positive (3+ by immunohistochemistry or positive by fluorescent in situ hybridization). ER-negative tumors were more likely to be HER-2 positive than were ER-positive tumors (odds ratio [OR] = 1.87, ER negative v ER positive; P < .001). For ER-positive tumors, risk of HER-2 positivity increased by grade (OR = 7.6, grade 3 v grade 1; P < .001) but not nodal status (OR = 1.3, four or more positive nodes v node negative; P = .08). Conversely, ER negative node-positive tumors were markedly more frequently HER-2 positive than node-negative cases (OR = 3.05, four or more positive nodes v node negative; P < .001) but independent of grade (OR = 0.82, grade 3 v grade 1; P = .76).

CONCLUSION

In early breast cancer patients selected for cytotoxic chemotherapy, we identified significant interactions between HER-2 and ER expression that correlate with tumor pathology. In ER-positive breast cancers, HER-2 expression correlates with grade, not nodal metastasis. In ER-negative breast cancers, HER-2 expression correlates with increased nodal positivity, not grade. ER and HER-2 expression may modify tumor pathology via ER/HER-2-mediated cross talk.

Aromatase inhibitors in post-menopausal metastatic breast carcinoma

To summarise the advances in the hormonal treatment of post-menopausal metastatic breast cancer, this paper reviews the published literature regarding the randomised trials comparing aromatase inhibitors (AIs) versus tamoxifen as a first-line therapeutic choice, or AIs versus megestrole acetate (MEG) as a second-line option. The pooled analysis of these authors on AI versus MEG as a second-line option for post-menopausal metastatic breast cancer suggested that AIs do not add any significant benefit over MEG in terms of overall response rate (ORR) and time to progression. According to the Cochrane Database, use of an AI as a second-line therapy versus any other endocrine therapy (mostly MEG) has shown a significant benefit in terms of overall survival, but not for progression-free survival, clinical benefit (CB) or ORR. Concerning the authors' comparisons between AIs versus tamoxifen as a first-line endocrine option in post-menopausal women with metastatic breast carcinoma, AIs seem to be superior to tamoxifen, with a significant benefit in terms of ORR, CB and time to progression being observed in favour of AIs over tamoxifen with fixed effects estimates. According to the Cochrane Database, there was an advantage to the use of AIs over tamoxifen in terms of progression-free survival and CB, but not for overall survival or ORR. With regards to toxicity, AIs show similar levels of hot flushes and arthralgia, increased risks of nausea, diarrhoea and vomiting, but a decreased risk of vaginal bleeding and thromboembolic events compared with other endocrine therapies. Weight gain, dyspnoea and peripheral oedema seem to be more frequent with MEG. At present, there is no proved overall survival difference in patients who are treated first with an AI and then with tamoxifen compared with the opposite sequence. In the metastatic setting, results are limited and are based on retrospective analyses.

Standardizing Slide-Based Assays in Breast Cancer: Hormone Receptors, HER2, and Sentinel Lymph Nodes

Despite the rapid expansion of novel diagnostics designed to personalize breast cancer care, there remain several significant unmet needs for improving the accuracy and reliability of tests that are already in common daily clinical practice. For example, although immunohistochemistry has been the predominant method for measuring estrogen receptor and progesterone receptor status for over 15 years, this assay remains unstandardized and there is a widespread concern that inaccuracy in immunohistochemistry technique and interpretation is leading to an unacceptably high error rate in determining the true hormone receptor status. Similarly, there is considerable concern that both false-negative and false-positive result rates for testing for HER2 status are unacceptably high in current clinical practice. This commentary considers a variety of factors, including preanalytic conditions and slide-scoring procedures, and other variables that may be contributing to current testing error rates and why there is a great need for the standardization of these biomarker assay procedures to further enable the highest possible quality of care for newly diagnosed breast cancer patients.

Amplified in Breast Cancer 1 in Human Epidermal Growth Factor Receptor–Positive Tumors of Tamoxifen-Treated Breast Cancer Patients

PURPOSE

Amplified in breast cancer 1 (AIB1) is a member of the p160/steroid receptor coactivators family and is involved in estrogen-dependent gene transcription by reducing the antagonistic activity of tamoxifen-bound estrogen receptor-alpha (ER-alpha). The present study was carried out to test the hypothesis that AIB1 protein expression and/or gene amplification mediates tamoxifen resistance in breast cancer.

EXPERIMENTAL DESIGN

Immunohistochemistry using AIB1 antibody and fluorescence in situ hybridization using probes specific for AIB1 and chromosome 20 was done on 402 ER-alpha-positive tamoxifen-treated breast cancers.

RESULTS

AIB1 overexpression was not associated with relapse during treatment with tamoxifen. In contrast, high AIB1 expression in patients with human epidermal growth factor receptor (HER) 2- and HER3-overexpressing tumors or tumors expressing one or more of HER1, HER2, or HER3 (HER1-3 positive) was associated with an increased risk of relapse on tamoxifen [hazard ratio, 2.20; 95% confidence interval, 1.07-3.52 (P = 0.0416); hazard ratio, 2.42; 95% confidence interval, 1.32-4.43 (P = 0.0030), respectively]. AIB1 gene amplification was observed in 18 of 362 (5%) patients. High AIB1 gene copy number had no effect on overall or disease-free survival.

CONCLUSIONS

Data presented here support a role for AIB1 expression on relapse during tamoxifen treatment in hormone-responsive HER-expressing clinical breast cancers and support clinical evidence, suggesting a cross-talk between ER-alpha and growth factor receptor pathways through changes in expression of specific coactivator proteins, such as AIB1. This study highlights the potential that tumor profiling, using multiple markers of treatment response, may improve patient selection for endocrine treatment, such as tamoxifen or aromatase inhibitors.

Multicenter phase II trial of neoadjuvant exemestane for postmenopausal patients with hormone receptor-positive, operable breast cancer: Saitama Breast Cancer Clinical Study Group (SBCCSG-03)

This multicenter phase II trial evaluated the efficacy and tolerability of 4 months of neoadjuvant exemestane in 44 postmenopausal patients with estrogen receptor (ER)-positive and/or progesterone receptor-positive, stage II to IIIB breast cancer measuring >or=3 cm. Pathological response was assessed by a central review board using response criteria proposed by the Japanese Breast Cancer Society. Clinical response [complete or partial response (PR)] was assessed by caliper, mammography, or ultrasound. Rates of breast-conserving surgery (BCS) and adverse events were also evaluated. A pathological response was observed in 13 (43%) of 30 patients who underwent surgery at 4 months. Fourteen patients were excluded from the pathological analysis: eight continued exemestane because of PR or stable disease (SD) at 4 months, three underwent chemotherapy because of progressive disease, and three underwent surgery within 2 months because of adverse events. A clinical response was seen in 27 (66%) of 41 evaluable patients. BCS was performed in 27 (90%) of 30 patients who underwent surgery at 4 months. Of the ten patients eligible for mastectomy at baseline, six chose to continue exemestane treatment without surgery because of a PR or SD at 4 months. Adverse events, most of which were grade 1, occurred in <or=10% of patients. These results suggest that neoadjuvant exemestane treatment is effective and well tolerated in postmenopausal women with ER-positive breast cancer. Further studies are required to determine the optimal duration of neoadjuvant treatment and to identify response criteria that can more accurately predict long-term outcomes.

PTK (protein tyrosine kinase)-6 and HER2 and 4, but not HER1 and 3 predict long-term survival in breast carcinomas

The HER receptors are of therapeutic and prognostic significance in breast cancer, and their function is modulated by cytoplasmic tyrosine kinases like PTK6 (brk). We performed a retrospective study on archival breast cancer samples from patients with long follow-up and compared the protein expression between individual HERs and between HERs and the PTK6. Univariate and multivariate analyses were used to study the prognostic value of parameters. Metastases-free survival of patients for longer than 240 months was inversely associated (P< or =0.05) with nodal status, tumour size, and oestrogen receptor status, but was also directly associated with high protein expression levels of HER4 and PTK6 in Kaplan-Meier analysis. In multivariate analysis for metastases-free survival of >240 months, the stepwise selected parameters were tumour size (relative risk 3.1), PTK6 expression (0.4), and number of positive lymph nodes (1.2). Furthermore, we demonstrated a timedependence of the prognostic value attributed to the parameters. The HER receptors (HER2,4), but not PTK6, were independent prognostic markers for metastases-free survival at 60 months, whereas at 240 months PTK6 is the strongest prognostic marker. We demonstrate that PTK6 is a prognostic marker of metastases-free survival in breast cancer, and is independent of the classical morphological and molecular markers of lymph node involvement, tumour size, and HER2 status.

Low expression of HER2 protein in breast cancer is biologically significant

HER2 status is routinely tested using immunohistochemistry or FISH following the licensing of a therapeutic agent targeting HER2. However, neither of these methods provides quantitative information relating to the 70-80% of patients with levels of expression lower than the assay detection thresholds. In this study, radioimmunohistochemistry was used to detect quantitative HER2 protein expression in 178 breast cancers. Survival analysis was performed, as were correlations with known prognostic variables and with overexpression of other HER family members. It is demonstrated that the populations expressing very high and very low levels of HER2 are each associated with increased risk of cancer-specific death on survival analysis (p = 0.0043). The group with low levels of HER2 was more likely to be of higher grade, EGFR-positive and ER/HER3/HER4-negative. HER2-positive cases were frequently ER-negative/HER3-positive, whilst cases with normal HER2 expression were often ER-positive/HER4-positive. The aggressive nature of the tumour group with low HER2 expression may be explained by actions of other HER family members, particularly EGFR, but whether these or other factors have a negative regulatory effect on HER2 expression remains to be determined.

Quantification of regulatory T cells enables the identification of high-risk breast cancer patients and those at risk of late relapse

PURPOSE

To assess the clinical significance of tumor-infiltrating FOXP3-positive regulatory T cells (TR) in breast cancer patients with long-term follow-up.

PATIENTS AND METHODS

FOXP3-positive TR were detected by immunohistochemistry with our new, extensively characterized FOXP3 monoclonal antibody, 236A/E7. Numbers of FOXP3-positive lymphocytes in tissue microarray cores from pure ductal carcinoma in situ (DCIS; n = 62), invasive breast cancer (n = 237) or from comparable areas of normal terminal duct lobular breast tissue (n = 10) were determined. A median cutoff of > or = 15 defined patients with high numbers of TR.

RESULTS

TR numbers were significantly higher in in situ and invasive breast carcinomas than in normal breast; invasive tumors have significantly higher numbers than DCIS (P = .001). High numbers of FOXP3-positive TR identified patients with DCIS at increased risk of relapse (P = .04) and patients with invasive tumors with both shorter relapse-free (P = .004) and overall survival (P = .007). High TR numbers were present in high-grade tumors (P < or = .001), in patients with lymph node involvement (P = .01), and in estrogen receptor (ER) -negative tumors (P = .001). Importantly, high numbers of TR within ER-positive tumors identified high-risk patients (P = .005). Unlike conventional clinicopathologic factors, high numbers of FOXP3-positive TR can identify patients at risk of relapse after 5 years.

CONCLUSION

These findings indicate that quantification of FOXP3-positive TR in breast tumors is valuable for assessing disease prognosis and progression, and that TR are an important therapeutic target for breast cancer. FOXP3-positive TR represent a novel marker for identifying late-relapse patients who may benefit from aromatase therapy after standard tamoxifen treatment.

Evaluation of oestrogen and progesterone receptor status in HER-2 positive breast carcinomas and correlation with outcome

AIM

HER-2/neu amplification occurs in 15-25% of breast carcinomas. This oncogene, also referred to as c-erbB-2, encodes a transmembrane tyrosine kinase receptor belonging to the epidermal growth factor receptor family. HER-2 over-expression is reported to be associated with a poor prognosis in breast carcinoma patients and in some studies is associated with a poorer response to anti-oestrogen therapy. These patients are less likely to benefit from CMF (cyclophosphamide, methotrexate, fluorouracil)-based chemotherapy compared with anthracycline-based chemotherapy. The aim of this study was to evaluate breast carcinomas to determine hormone receptor status and if there is a difference in breast cancer specific survival for HER-2 positive patients.

METHODS

A total of 591 breast carcinomas were evaluated using immunohistochemistry (IHC) for oestrogen receptor (ERp), progesterone receptor (PRp) and three different HER-2 antibodies (CB11, A0485 and TAB250). Percentage of tumour cells and intensity of staining for ERp were evaluated using a semiquantitative method.

RESULTS

Of the 591 tumours, 91 (15.4%) showed 3+ membrane staining for HER-2 with one or more antibodies. Of these 91 tumours, 41 (45.1%) were ERp+/PRp+, seven (7.7%) were ERp+/PR-, six (6.6%) were ERp-/PRp+ and 37 (40.7%) were ERp-/PR-. Of HER-2 positive tumours, 5.5% showed >80% 3+ staining for ERp compared with 31.8% of 0-2+ HER-2 tumours; 24.2% of HER-2-positive tumours showed 60% or more cells with 2+ or 3+ staining for ERp. Treatment data were available for 209 patients and no difference was observed in breast cancer specific survival (BCSS) with HER-2 status and tamoxifen.

CONCLUSION

Oestrogen receptor status cannot be used to select tumours for evaluation of HER-2 status, and oestrogen and progesterone receptor positivity does not preclude a positive HER-2 status. There is a higher proportion of ERp negative tumours associated with HER-2 positivity, however, more than 20% of HER-2 positive tumours show moderate or strong staining for ERp. HER-2 positive patients in this study did not show an adverse BCSS with tamoxifen treatment unlike some previous studies.

Hormonal therapy for postmenopausal breast cancer: the science of sequencing

Oestrogens play important roles in the natural history of breast cancer. Consequently, therapies have been developed to reduce oestrogen levels or to block signalling through oestrogen receptors (ER). These therapies include tamoxifen, selective oestrogen receptor modulators (SERMs), aromatase inhibitors (AIs) and selective oestrogen receptor downregulators (SERDs). All have proven clinical efficacy in postmenopausal women with ER-positive breast cancer and can be effective in the neoadjuvant and adjuvant settings, and in the management of advanced disease. This range of endocrine therapies offers the opportunity for prolonging benefit from treatment and delaying tumour recurrence/progression by combining the different classes of drugs or by using them sequentially. Evaluation of the potential clinical benefits of concomitant or sequential endocrine therapies should be based on considerations of efficacy and safety profiles, mechanisms of action/resistance and effects on tumour biology. Evidence from preclinical models and from randomized clinical trials in patients with postmenopausal breast cancer suggests that concomitant endocrine therapies are no more effective than AIs alone. However, using AIs either as initial therapy or sequentially after tamoxifen appears to produce more benefits beyond the use of tamoxifen alone.Currently, there are no proven algorithms for the planned, sequential use of the full range of endocrine therapies, particularly for the majority of patients who present with early breast cancer. Prospective, randomized clinical trials are needed to determine the best use of therapies in particular settings, taking into account the spectrum of molecular phenotypes in different tumours.

Evidence-Based Neoadjuvant Endocrine Therapy for Breast Cancer

Breast cancer is the most common malignancy among women in Western countries. The management of patients with nonmetastatic breast cancer with primary endocrine therapy has evolved dramatically in the past decade. Neoadjuvant treatment has been used to turn inoperable tumors into operable tumors and also to downstage tumors. Hormone receptor-positive breast tumors exposed to neoadjuvant chemotherapy have lower rates of pathologic complete response than hormone receptor-negative tumors. Recently, clinical trials showed an increased response rate and a higher rate of breast-conserving surgery with aromatase inhibitors compared with tamoxifen. Exploratory data suggest that predictive markers of response include a higher estrogen receptor expression level and a negative HER2 status. With the introduction of "biologic" agents and surrogate markers like Ki-67, several studies are evaluating which patients are more likely to respond to preoperative hormonal agents. This review summarizes recent data on neoadjuvant endocrine therapy for breast cancer and the implication of predictive markers of response into clinical practice and future research.