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

Overcoming resistance and restoring sensitivity to HER2-targeted therapies in breast cancer

BACKGROUND

Approximately 15%-23% of breast cancers overexpress human epidermal growth factor receptor 2 (HER2), which leads to the activation of signaling pathways that stimulate cell proliferation and survival. HER2-targeted therapy has substantially improved outcomes in patients with HER2-positive breast cancer. However, both de novo and acquired resistance are observed.

DESIGN

A literature search was performed to identify proposed mechanisms of resistance to HER2-targeted therapy and identified novel targets in clinical development for treating HER2-resistant disease.

RESULTS

Proposed HER2-resistance mechanisms include impediments to HER2-inhibitor binding, signaling through alternative pathways, upregulation of signaling pathways downstream of HER2, and failure to elicit an appropriate immune response. Although continuing HER2 inhibition beyond progression may provide an additional clinical benefit, the availability of novel therapies targeting different mechanisms of action could improve outcomes. The developmental strategy with the most available data is targeting the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (mTOR) pathway. The oral mTOR inhibitor everolimus has shown promising activity in combination with chemotherapy and trastuzumab in trastuzumab-refractory, advanced breast cancer.

CONCLUSIONS

Non-HER2-targeted therapy is a promising means of overcoming resistance to HER2-targeted treatment. Ongoing clinical studies will provide additional information on the efficacy and safety of novel targeted therapies in HER2-resistant advanced breast cancer.

BRCA1 germ-line mutations and tumor characteristics in eastern Chinese women with familial breast cancer

Although several studies detected the BRCA1 germ-line mutations in Chinese women with familial breast cancer, most of them did not employ conventional full gene sequencing, especially in eastern China. In addition, the clinicopathological features of BRCA1-associated breast cancer in Chinese women were not well investigated. In this study, we screened the complete coding regions and exon-intron boundaries of BRCA1 by polymerase chain reaction (PCR)-sequencing assay. Immunohistochemistry analyses were performed on tumor samples to detect the expression of estrogen receptor (ER), progesterone receptor (PR), P53, and human epidermal growth factor receptor-2 (HER-2). Breast cancer patients having one or more affected relatives referred from the Zhejiang Cancer Hospital, eastern China during 2008-2011 were selected for the study. A total of 62 familial breast cancer patients received the BRCA1 germ-line mutation screening. Five deleterious mutations were detected in this cohort. The mutation rate was 11.3% (7/62). We found two novel mutations (3414delC and 5,280 C > T) and two recurrent mutations (5,273 G > A and 5589del8). BRCA1 mutation tumors tended to be negative for ER, PR, and HER-2, and exhibited high histological grade compared with tumors without BRCA1 mutations. Our study suggests that recurrent mutations may exist in eastern Chinese women with familial breast cancer and PCR-sequencing assay is a useful tool to screen these mutations. It also suggests that BRCA1-associated breast cancers in Chinese women exhibit an aggressive phenotype.

The adjuvant treatment of HER2-positive breast cancer

OPINION STATEMENT

About 15-20% of patients with early stage breast cancer present with tumors that have overexpression or amplification of the human epidermal growth factor receptor 2 (HER2) gene. Before 2005, these individuals had an increased risk of recurrence and death, but since then their outcomes have substantially improved with the adoption in most countries of adjuvant trastuzumab as a standard component of therapy for HER2-positive early-stage breast cancer. Consequently, access to high-quality and accurate HER2 testing methods is critical to accurately determine HER2 status, guide treatment decisions, and ultimately improve clinical outcomes. In 2012, the humanized monoclonal anti-HER antibody trastuzumab was the only approved HER2-targeted therapy in the adjuvant setting. Data from the first generation of trials combining it with various chemotherapy regimens showed significant improvements in disease-free and overall survival (DFS/OS). Based on results from five randomized clinical trials, a trastuzumab-containing regimen for up to 1 year is now considered standard for all patients with HER2-positive tumors larger than 1 cm in size who would have fulfilled eligibility to those studies, and this recommendation is sometimes extended to patients with stage I tumors greater than 0.5 cm (T1b). Second generation adjuvant studies with other HER2-targeted agents like lapatinib and pertuzumab are ongoing, and newer drugs like T-DM1 and neratinib are being actively tested in the metastatic setting.

Neratinib (HKI-272) in the treatment of breast cancer

Neratinib is an orally available, small, irreversible, pan-HER kinase inhibitor. HER-2-positive breast cancer is a breast cancer subtype with an increasing body of knowledge regarding potential targeted drug combinations that are significantly improving outcomes through a biologically tailored therapy approach; neratinib emerges as a promising tool in this context. This article reviews the molecular and clinical development of neratinib, an example of a covalent drug, from preclinical models to Phase III clinical trials, focusing on breast cancer treatment. The potential combinations of neratinib with chemotherapy in the metastatic, adjuvant and even neoadjuvant settings are appraised. These results and future perspectives will be discussed.

Lapatinib in patients with metastatic breast cancer following initial treatment with trastuzumab: an economic analysis from the Brazilian public health care perspective

OBJECTIVE

To evaluate, from the perspective of the Brazilian public health care system, the cost-effectiveness of lapatinib plus capecitabine (LAP/CAP) versus capecitabine alone (CAP) or trastuzumab plus capecitabine (TRAST/CAP) in the treatment of women with human epidermal growth factor receptor-2-positive metastatic breast cancer previously treated with trastuzumab.

METHODS

An economic model was developed to compare costs and clinical outcomes over a 5-year time horizon. Both costs and outcomes were discounted at a 5% rate, in accordance with Brazilian pharmacoeconomic guidelines. Clinical inputs were determined using indirect treatment comparisons. Costs were derived from public reimbursement databases and reported in 2010 Brazilian real (R$1 = USD$0.52). Clinical outcomes included progression-free survival years (PFYs), life-years (LYs) and quality-adjusted life-years (QALYs). The economic outcome was the incremental cost per LY, PFY, or QALY gained. The impact of variations in individual inputs (eg, drug cost, drug effectiveness) was examined using one-way sensitivity analyses. Overall model robustness was tested using probabilistic sensitivity analyses, varying the ranges of all input parameters within their standard distributions.

RESULTS

Expected cost per patient was R$41,195 for CAP, R$95,256 for LAP/CAP, and R$113,686 for TRAST/CAP. Respective LYs were 1.406, 1.695, and 1.465; PFYs were 0.473, 0.711, and 0.612; and QALYS were 0.769, 0.958, and 0.827. LAP/CAP dominated TRAST/CAP for all outcomes. Incremental cost-effectiveness ratios of LAP/CAP over CAP were R$186,563 for LYs, R$226,403 for PFYs, and R$284,864 for QALYs. Results remained unchanged in one-way sensitivity analyses. In probabilistic analyses, LAP/CAP was dominant over TRAST/CAP in 93.5% of simulations.

CONCLUSION

LAP/CAP increases survival for women with human epidermal growth factor receptor-2-positive metastatic breast cancer. LAP/CAP is cost-effective against TRAST/CAP (ie, produces more benefits at a lower cost) and can be considered cost-effective over CAP at a willingness-to-pay of about R$290,000 (US$151,000) per QALY gained.

Trastuzumab emtansine for HER2-positive advanced breast cancer

BACKGROUND

Trastuzumab emtansine (T-DM1) is an antibody-drug conjugate incorporating the human epidermal growth factor receptor 2 (HER2)-targeted antitumor properties of trastuzumab with the cytotoxic activity of the microtubule-inhibitory agent DM1. The antibody and the cytotoxic agent are conjugated by means of a stable linker.

METHODS

We randomly assigned patients with HER2-positive advanced breast cancer, who had previously been treated with trastuzumab and a taxane, to T-DM1 or lapatinib plus capecitabine. The primary end points were progression-free survival (as assessed by independent review), overall survival, and safety. Secondary end points included progression-free survival (investigator-assessed), the objective response rate, and the time to symptom progression. Two interim analyses of overall survival were conducted.

RESULTS

Among 991 randomly assigned patients, median progression-free survival as assessed by independent review was 9.6 months with T-DM1 versus 6.4 months with lapatinib plus capecitabine (hazard ratio for progression or death from any cause, 0.65; 95% confidence interval [CI], 0.55 to 0.77; P<0.001), and median overall survival at the second interim analysis crossed the stopping boundary for efficacy (30.9 months vs. 25.1 months; hazard ratio for death from any cause, 0.68; 95% CI, 0.55 to 0.85; P<0.001). The objective response rate was higher with T-DM1 (43.6%, vs. 30.8% with lapatinib plus capecitabine; P<0.001); results for all additional secondary end points favored T-DM1. Rates of grade 3 or 4 adverse events were higher with lapatinib plus capecitabine than with T-DM1 (57% vs. 41%). The incidences of thrombocytopenia and increased serum aminotransferase levels were higher with T-DM1, whereas the incidences of diarrhea, nausea, vomiting, and palmar-plantar erythrodysesthesia were higher with lapatinib plus capecitabine.

CONCLUSIONS

T-DM1 significantly prolonged progression-free and overall survival with less toxicity than lapatinib plus capecitabine in patients with HER2-positive advanced breast cancer previously treated with trastuzumab and a taxane. (Funded by F. Hoffmann-La Roche/Genentech; EMILIA ClinicalTrials.gov number, NCT00829166.).

Trastuzumab as first-line therapy in HER2-positive metastatic breast cancer patients

Trastuzumab is a humanized monoclonal antibody against the extracellular domain of hEGF receptor-2 (HER2). Trastuzumab in combination with chemotherapy has proven efficacy in treating both early and metastatic HER2-positive breast cancer. In the metastatic setting, the addition of trastuzumab to chemotherapy is associated with a statistically significant longer time to disease progression, higher rate of objective response and improvement in overall survival. Trastuzumab efficacy is not influenced by hormone receptor status, but differences in median overall survival exist between HER2-positive and HER2-negative states. Reassessment of the benefit of re-exposing patients with metastatic breast cancer to trastuzumab following relapse in the adjuvant setting is necessary. Ongoing research into new HER2-targeted therapies and trials involving combination anti-HER2 drug therapy without chemotherapy show promise. This review is focused on the available results obtained with the use of trastuzumab in the subset of HER2-positive breast cancer patients with metastatic disease.

Overcoming treatment resistance in HER2-positive breast cancer: potential strategies

Human epidermal growth factor receptor (HER)-2 overexpression or amplification occurs in about 20% of all breast cancers and results in a worse prognosis. Nevertheless, anti-HER2 treatments have recently been developed, resulting in dramatic improvements in the clinical outcome of patients with HER2-positive breast cancer. Trastuzumab has shown efficacy in early and advanced breast cancer treatment and lapatinib is currently approved for the treatment of advanced disease. Other anti-HER2 agents are being investigated. Mechanisms of resistance to trastuzumab treatment include crosstalk with heterologous receptors and amplification of HER2 signalling; amplification of the phosphoinositide 3-kinase (PI3K)/AKT pathway; alteration in binding of trastuzumab to HER2; and loss of HER2 expression. Proposed mechanisms of resistance to lapatinib involve derepression and/or activation of compensatory survival pathways through increased PI3K/AKT or estrogen receptor (ER) signalling. Several strategies to overcome resistance to anti-HER2 treatment are in different phases of development and include treatment with pertuzumab, T-DM1 and mammalian target of rapamycin (mTOR) inhibitors.

Pertuzumab in HER2-positive breast cancer

BACKGROUND

Lack of response in some patients and relapse during the course of therapy in the treatment of HER2-positive early breast cancer and metastatic breast cancer continue to challenge researchers and clinicians towards a better understanding of the fundamental mechanisms of trastuzumab action and new therapies for HER2. The aim of this review is to discuss current and future treatment options with pertuzumab in the light of new insights into HER2-positive breast cancer.

SCOPE

Pertuzumab showed positive results in clinical studies and agents in routine clinical usage are updated. The PubMed database, ASCO and San Antonio Breast Cancer Symposium Meeting abstracts were searched up to June 2012 by using the terms 'pertuzumab' and 'anti-HER2 treatment'; papers which were considered relevant for the aim of this review were selected by the authors.

FINDINGS

The presented trials of phase II and phase III randomized trials of CLEOPATRA, NEOSPHERE and TRYPHAENA have showed pertuzumab action to be complementary to trastuzumab without increasing adverse events. Adding pertuzumab to trastuzumab in the first line of HER2-positive metastatic breast cancer and in the neoadjuvant treatment of locally advanced HER2-positive breast cancer is usually well tolerated. The evaluation of health-related quality of life showed that combining pertuzumab with docetaxel and trastuzumab compared to placebo have no detrimental effect with adding pertuzumab.

CONCLUSION

Pertuzumab is the first HER dimerization inhibitor with a mechanism of action complementary to trastuzumab. Studies with anti-HER2 combination treatments indicate that the use of more than one HER2-targeted therapy was superior to one of these agents alone. Pertuzumab has produced impressive anti-tumor activity in combination with trastuzumab. There are ongoing studies with pertuzumab with an increasing tendency towards moving the study of these agents to earlier stages of the disease, namely in the adjuvant and neoadjuvant setting.

Biomarkers in Breast Cancer - An Update

The therapy of choice for breast cancer patients requiring adjuvant chemo- or radiotherapy is increasingly guided by the principle of weighing the individual effectiveness of the therapy against the associated side effects. This has only been made possible by the discovery and validation of modern biomarkers. In the last decades and in the last few years some biomarkers have been integrated in clinical practice and a number have been included in modern study concepts. The importance of biomarkers lies not merely in their prognostic value indicating the future course of disease but also in their use to predict patient response to therapy. Due to the many subgroups, mathematical models and computer-assisted analysis are increasingly being used to assess the prognostic information obtained from established clinical and histopathological factors. In addition to describing some recent computer programmes this overview will focus on established molecular markers which have already been extensively validated in clinical practice and on new molecular markers identified by genome-wide studies.

Synthesis of site-specific antibody-drug conjugates using unnatural amino acids

Antibody-drug conjugates (ADCs) allow selective targeting of cytotoxic drugs to cancer cells presenting tumor-associated surface markers, thereby minimizing systemic toxicity. Traditionally, the drug is conjugated nonselectively to cysteine or lysine residues in the antibody. However, these strategies often lead to heterogeneous products, which make optimization of the biological, physical, and pharmacological properties of an ADC challenging. Here we demonstrate the use of genetically encoded unnatural amino acids with orthogonal chemical reactivity to synthesize homogeneous ADCs with precise control of conjugation site and stoichiometry. p-Acetylphenylalanine was site-specifically incorporated into an anti-Her2 antibody Fab fragment and full-length IgG in Escherichia coli and mammalian cells, respectively. The mutant protein was selectively and efficiently conjugated to an auristatin derivative through a stable oxime linkage. The resulting conjugates demonstrated excellent pharmacokinetics, potent in vitro cytotoxic activity against Her2(+) cancer cells, and complete tumor regression in rodent xenograft treatment models. The synthesis and characterization of homogeneous ADCs with medicinal chemistry-like control over macromolecular structure should facilitate the optimization of ADCs for a host of therapeutic uses.

Met receptor acts uniquely for survival and morphogenesis of EGFR-dependent normal mammary epithelial and cancer cells

Mammary gland development and breast cancer growth require multiple factors both of endocrine and paracrine origin. We analyzed the roles of Epidermal Growth Factor Receptor (EGFR) and Hepatocyte Growth Factor Receptor (Met) in mammary epithelial cells and mammary tumor cells derived from a mutated-ErbB2 transgenic mice. By using highly specific tyrosine kinase inhibitors we found that MCF-10A and NMuMG mammary epithelial cell lines are totally dependent on EGFR activation for their growth and survival. Proliferation and 3D-morphogenesis assays showed that HGF had no role in maintaining mammary cell viability, but was the only cytokine able to rescue EGFR-inhibited mammary cells. Insulin-Like Growth Factor-I (IGF-I), basic-Fibroblast Growth Factor (b-FGF) and Neuregulin, which are well known mammary morphogenic factors, did not rescue proliferation or morphogenesis in these cell lines, following EGFR inhibition. Similarly, ErbB2-driven tumor cells are EGFR-dependent and also display HGF-mediated rescue. Western-blot analysis of the signaling pathways involved in rescue after EGFR inhibition indicated that concomitant ERK1/2 and AKT activation was exclusively driven by Met, but not by IGF-I or b-FGF. These results describe a unique role for EGFR and Met in mammary epithelial cells by showing that similar pathways can be used by tumorigenic cells to sustain growth and resist to EGFR-directed anti-tumorigenic drugs.

Human responses against HER-2-positive cancer cells in human immune system-engrafted mice

Background:

Human immune system (HIS)-engrafted mice are new tools to investigate human immune responses. Here, we used HIS mice to study human immune responses against human HER-2-positive cancer cells and their ability to control tumour growth and metastasis.

Methods:

BALB/c Rag2^−/−, Il2rg^−/− mice were engrafted with CD34⁺ or CD133⁺ human cord blood hematopoietic stem cells (HSC) and vaccinated with human HER-2-positive cancer cells SK-OV-3 combined to human IL-12.

Results:

Both CD34⁺ or CD133⁺ human HSC gave long-term engraftment and differentiation, both in peripheral blood and in lymphoid organs, and production of human antibodies. Vaccinated mice produced specific anti-HER-2 human IgG. An s.c. SK-OV-3 challenge was significantly inhibited (but not abolished) in both vaccinated and non-vaccinated HIS mice. Tumours were heavily infiltrated with human and murine cells, mice showed NK cells and production of human interferon-γ, that could contribute to tumour growth inhibition. Vaccinated HIS mice showed significantly inhibited lung metastases when compared with non-vaccinated HIS mice and to non-HIS mice, along with higher levels of tumour-infiltrating human dendritic cells.

Conclusion:

Anti-HER-2 responses were elicited through an adjuvanted allogeneic cancer cell vaccine in HIS mice. Human immune responses elicited in HIS mice effectively inhibited lung metastases.

Novel targeted agents for the treatment of advanced breast cancer

The discovery of the molecular processes involved in cancer development has led to the design of an array of targeted agents. These agents, directed to specific proteins in the machinery of cancer cells, interfere with vital cascades involved in cell invasion, metastasis, apoptosis, cell-cycle control and angiogenesis. In breast cancer, the main pathways studied and targeted by drugs are the HER2 pathway, EGFR, VEGF, PI3K/Akt/mammalian target of rapamycin (PI3K-M-Tor), IGF/IGFR, poly(ADP ribose) polymerase 1, HDAC and many others. In this review, we present the most promising studies of these new targeted therapies and novel combination of targeted therapies with cytotoxic agents for the treatment of breast cancer patients.

A multicenter, phase II study of epirubicin/cyclophosphamide followed by docetaxel and concurrent trastuzumab as primary systemic therapy for HER-2 positive advanced breast cancer (the HER2NAT study)

BACKGROUND

The outcome in patients with human epidermal growth factor receptor-2 (HER-2)-positive locally advanced breast cancer may be improved by integrating trastuzumab with primary systemic therapy (PST).

METHODS

The efficacy and safety of PST comprising EC (epirubicin 90 mg/m(2) and cyclophosphamide 600 mg/m(2), four cycles every 3 weeks) followed by docetaxel (75 mg/m(2), four cycles every 3 weeks) and concurrent trastuzumab (loading dose 4 mg/kg followed by 2 mg/kg, 12 cycles every week) was investigated in a multicenter, prospective, phase II study in patients with HER-2-positive stage IIIB/IIIC/IV breast cancer. The primary endpoint was pathologic complete response (pCR) including the tumor intraductal component confirmed by central pathologic review.

RESULTS

In total, 38 patients were enrolled (stage IIIB, 63.2 %; IIIC, 23.7 %; IV, 13.2 %; estrogen receptor- and/or progesterone receptor-positive, 47.4 %). The pCR rate was 16.2 % in the primary tumor (six of 37 patients in the Full Analysis Set) and 56.8 % (21/37) in the ipsilateral axillary lymph nodes. Treatment was given according to protocol in 28 of 37 patients; six of 28 in the Per-Protocol Set achieved pCR (21.4 %). The clinical response rate was 67.6 % (25/37 patients; complete response, 13.5 %; partial response, 54.1 %). No patients developed congestive heart failure; however, three patients had a non-symptomatic decrease of >10 % of left ventricular ejection fraction.

CONCLUSIONS

PST including concurrent use of trastuzumab combined with docetaxel is effective and well-tolerated in HER-2-positive advanced breast cancer patients, including those patients requiring mastectomy for local control.

Reduced in vivo lung metastasis of a breast cancer cell line after treatment with Herceptin mAb conjugated to chemotherapeutic drugs

Anthracyclines and taxanes have remarkable anticancer efficacy, but have poor selectivity and high toxicity. Targeted delivery of chemotherapeutics has emerged as a strategy to achieve higher drug levels at the tumor site, to spare noncancerous tissue and potentially to use lower systemic drug doses, thus preventing side effects. In this study, we targeted the HER2 receptor using the monoclonal antibody (mAb) Herceptin (Trastuzumab) chemically conjugated to Doxorubicin or Taxol. In vitro, drug-Herceptin conjugates exhibited cytotoxicity comparable to equimolar concentrations of free drugs, with the benefit that the cytotoxicity of the conjugates was selective for cells expressing the HER2 target. In vivo, treatment of tumor-bearing mice with Taxol-Herceptin conjugates had a reduction of primary tumors comparable to equivalent doses of free drugs. However, Taxol-Herceptin conjugates significantly reduced metastasis compared with equivalent doses of free drugs. Thus, the data support the concept that conjugates might target metastasis better than primary tumors. This would offer a potential therapeutic approach for management of metastatic breast cancer.

Tapping the potential of quantum dots for personalized oncology: current status and future perspectives

Cancer is one of the most serious health threats worldwide. Personalized oncology holds potential for future cancer care in clinical practice, where each patient could be delivered individualized medicine on the basis of key biological features of an individual tumor. One of the most urgent problems is to develop novel approaches that incorporate the increasing molecular information into the understanding of cancer biological behaviors for personalized oncology. Quantum dots are a heterogeneous class of engineered fluorescent nanoparticles with unique optical and chemical properties, which make them promising platforms for biomedical applications. With the unique optical properties, the utilization of quantum dot-based nanotechnology has been expanded into a wide variety of attractive biomedical applications for cancer diagnosis, monitoring, pathogenesis, treatment, molecular pathology and heterogeneity in combination with cancer biomarkers. Here, we focus on the clinical application of quantum dot-based nanotechnology in personalized oncology, covering topics on individualized cancer diagnosis and treatment by in vitro and in vivo molecular imaging technologies, and in-depth understanding of the biological behaviors of tumors from a nanotechnology perspective. In addition, the major challenges in translating quantum dot-based nanotechnology into clinical application and promising future directions in personalized oncology are also discussed.

Gene expression analysis in biomarker research and early drug development using function tested reverse transcription quantitative real-time PCR assays

The identification of new biomarkers is essential in the implementation of personalized health care strategies that offer new therapeutic approaches with optimized and individualized treatment. In support of hypothesis generation and testing in the course of our biomarker research an online portal and respective function-tested reverse transcription quantitative real-time PCR assays (RT-qPCR) facilitated the selection of relevant biomarker genes. We have established workflows applicable for convenient high throughput gene expression analysis in biomarker research with cell lines (in vitro studies) and xenograft mouse models (in vivo studies) as well as formalin-fixed paraffin-embedded tissue (FFPET) sections from various human research and clinical tumor samples. Out of 92 putative biomarker candidate genes selected in silico, 35 were shown to exhibit differential expression in various tumor cell lines. These were further analysed by in vivo xenograft mouse models, which identified 13 candidate genes including potential response prediction biomarkers and a potential pharmacodynamic biomarker. Six of these candidate genes were selected for further evaluation in FFPET samples, where optimized RNA isolation, reverse transcription and qPCR assays provided reliable determination of relative expression levels as precondition for differential gene expression analysis of FFPET samples derived from projected clinical studies. Thus, we successfully applied function tested RT-qPCR assays in our biomarker research for hypothesis generation with in vitro and in vivo models as well as for hypothesis testing with human FFPET samples. Hence, appropriate function-tested RT-qPCR assays are available in biomarker research accompanying the different stages of drug development, starting from target identification up to early clinical development. The workflow presented here supports the identification and validation of new biomarkers and may lead to advances in efforts to achieve the goal of personalized health care.

Targeted therapy for gastric cancer--current status

In patients with metastatic gastric cancer, median overall survival remains under 1 year and standard chemotherapy regimens are not able to substantially improve the prognosis of the patients. Amplification and over-expression of HER2 is reported in approximately 20% of gastric tumours, challenging the use of targeted therapies. There are several targeted therapies in different stages of clinical development with trastuzumab being the first overcoming the regulatory hurdle and getting European Medicines Agency approval. In patients with advanced gastric or gastro-oesophageal junction cancer, addition of trastuzumab to chemotherapy significantly improved overall survival compared with chemotherapy alone. Addition of trastuzumab to chemotherapy did not increase the incidence of adverse events. Other agents targeting the HER2 pathway (lapatinib) or other domains of epidermal growth factor receptor family (cetuximab) are currently being investigated for the treatment of an advanced gastric cancer.

Targeting breast cancer vaccines to dendritic cells: improved immunological responses with less protein?

The central goal of cancer immunotherapy is to control tumors through the mobilization of the patient's immune system. Vaccines targeting the Her2/neu proto-oncogene have been tested with some early encouraging responses in breast cancer. However, a more effective set of vaccines targeting specific immune cell subtypes may provide a more potent means to stimulate anti-tumor immunity. Dendritic cell-specific antibodies fused with the Her2/neu protein proved effective at generating immune responses in preclinical models. Importantly, only low amounts of protein vaccine were required to generate this response, which has potentially significant implications for the future clinical development of Her2/neu-targeted vaccines and other vaccine targets.

Spatial regulation of receptor tyrosine kinases in development and cancer

During development and tissue homeostasis, patterns of cellular organization, proliferation and movement are highly choreographed. Receptor tyrosine kinases (RTKs) have a crucial role in establishing these patterns. Individual cells and tissues exhibit tight spatial control of the RTKs that they express, enabling tissue morphogenesis and function, while preventing unwarranted cell division and migration that can contribute to tumorigenesis. Indeed, RTKs are deregulated in most human cancers and are a major focus of targeted therapeutics. A growing appreciation of the essential role of spatial RTK regulation during development prompts the realization that spatial deregulation of RTKs is likely to contribute broadly to cancer development and may affect the sensitivity and resistance of cancer to pharmacological RTK inhibitors.

Association of HER-2 copy number and HER-2/CEP-17 ratio with neoadjuvant taxane-containing chemotherapy sensitivity in locally advanced breast cancer

PURPOSE

Aneusomy 17 causes inconsistency in fluorescence in situ hybridization (FISH)-based human epidermal growth factor receptor (HER)-2 status assessment using different algorithms (copy number or the HER-2/centromere enumerator probe 17 [CEP-17] ratio). We investigated the effects of FISH-based HER-2 status assessment and aneusomy 17 on responsiveness to neoadjuvant chemotherapy (NAC).

PATIENTS AND METHODS

This prospective study recruited 152 patients with locally advanced breast cancer who underwent four-cycle weekly paclitaxel plus carboplatin without trastuzumab.

RESULTS

The pathologic complete remission (pCR) rate in the breast and axilla was 24.3% (95% confidence interval [CI], 17.7%-32.0%). Although HER-2 status, assessed by either HER-2/CEP-17 ratio-based FISH or copy number-based FISH, was a predictor of NAC sensitivity, ratio-assessed HER-2 status had a poorer performance in determining patients' responsiveness to NAC (p = .029). Patients who were not HER-2 amplified when assessed using the HER-2/CEP-17 ratio but were HER-2 amplified when assessed using copy number (~5%) were eventually proven to be responsive to NAC, with a pCR rate of 57% (95% CI, 18.4%-90.1%). In contrast, patients who were HER-2 amplified when assessed by the ratio but not HER-2 amplified when assessed using copy number (~3%) were completely irresponsive. Higher HER-2 copy numbers represented increasing chances of a pCR (adjusted odds ratio, 3.09; 95% CI, 1.35-7.08), with an apparent gene-dose effect (p for trend < .001).

CONCLUSION

It is likely that HER-2 copy number but not the HER-2/CEP-17 ratio determines NAC sensitivity. Additional studies to validate our findings are warranted.

Efficacy of primed in situ labelling in determination of HER-2 gene amplification and CEN-17 status in breast cancer tissue

Considerable attention has been given to the accuracy of HER-2 testing and the correlation between the results of different testing methods. This interest reflects the growing importance of HER-2 status in the management of patients with breast cancer. In this study the detection of HER-2 gene and centromere 17 status was evaluated using dual-colour primed in situ labelling (PRINS) in comparison with fluorescence in situ hybridization (FISH). These two methods were evaluated on a series of 27 formalin fixed paraffin embedded breast carcinoma tumours, previously tested for protein overexpression by HercepTest (grouped into Hercep 1+/0, 2+ and 3+). HER-2 gene amplification (ratio ≥ 2.2) by PRINS was found in 3:3, 6:21 and 0:3 in IHC 3+, 2+ and 1+/0 cases, respectively. Comparing FISH and IHC (immunohistochemistry), showed the same results as for PRINS and IHC. Chromosome 17 aneusomy was found in 10 of 21 IHC 2+ cases (47.6%), of which 1 (10%) showed hypodisomy (chromosome 17 copy number per cell ≤ 1.75), 7 (70%) showed low polysomy (chromosome 17 copy number per cell=2.26 - 3.75) and 2 (20%) showed high polysomy (chromosome 17 copy number per cell ≥ 3.76). The overall concordance of detection of HER-2 gene amplification by FISH and PRINS was 100% (27:27). Furthermore, both the level of HER-2 amplification and copy number of CEN17 analysis results correlated well between the two methods. In conclusion, PRINS is a reliable, reproducible technique and in our opinion can be used as an additional test to determine HER-2 status in breast tumours.

Trastuzumab for small HER-2+ breast cancer: small tumor, big decision

A 53-year-old postmenopausal woman was found to have a new area of microcalcification at the 10 o'clock position of her right breast during a routine screening mammogram. Ultrasound-guided core biopsy revealed a grade 2 invasive ductal carcinoma, estrogen receptor (ER)+ (90%), progesterone receptor positive (20%), and human epidermal growth factor receptor (HER)-2+ (3+ by immunohistochemistry). A right breast lumpectomy and sentinel node biopsy were performed. The invasive tumor measured 0.7 cm, no lymphovascular space invasion was identified, surgical margins were uninvolved, and the sentinel lymph nodes were negative for tumor. She was evaluated postoperatively in the medical oncology clinic to discuss an adjuvant treatment strategy. The question for our colleagues is: should she be offered adjuvant chemotherapy and trastuzumab prior to adjuvant radiation and 5 years of hormonal therapy?

Omics and its potential impact on R&D and regulation of complex herbal products

In traditional Chinese medicine (TCM), multicomponent and principally plant-derived drugs are used for disease prevention, symptom amelioration and treatment in a personalized manner. Because of their complex composition and consequent multiple targets and treatment objectives, the application of omics techniques and other integrative approaches seems inherently appropriate and even necessary for the demonstration of their potential preclinical and clinical safety and efficacy. This perspectives article provides proposals for the application of omics methods to the investigation of complex herbal products (CHP),(1) including Chinese herbal medicines (CHM), both in vitro and in vivo, for preclinical and clinical toxicity, pharmacokinetics, pharmacodynamics and efficacy tests. Ultimately, such approaches could aid regulatory scrutiny and potential acceptance, although currently there is no regulatory requirement of omics-based data in any submitted dossier to any regulatory agency, including for conventional drugs and CHP. However, it has been acknowledged that such studies are being increasingly performed, and almost surely will eventually be included into regulatory submission dossiers, possibly initially as supplementary materials. Specifically for CHM and CHP, omics can play a role both in determining product composition and its variability and in monitoring biological effects in carefully selected platforms. Predicting the future is difficult, but it seems possible that regulatory acceptance of omics techniques and a systems biology approach for the study of TCM, CHM and CHP will not be long delayed. It is expected that current studies and plans employing omics techniques and other integrative approaches will prove to be positive and informative.

Molecular prescreening to select patient population in early clinical trials

The efficacy of targeted therapies in patient populations selected for treatment on the basis of the molecular features of their tumours is shifting the current focus of treatment to biomarker-driven clinical trials. Phase I trials provide an arena for early hypothesis testing, examining not only safety and toxicity, but also target engagement, biologically effective dosages, and the appropriate patient population. In this Perspectives article, we describe this new trend in early drug development, establishing the different approaches for building a pre-screening programme in an academic institution that is involved in early drug development. Our experience establishing the phase I programme at Vall d'Hebrón serves as an example of how these approaches can be integrated in ongoing trials, and we believe these considerations will help others to implement similar programmes in their institutions.

Toward individualized breast cancer therapy: translating biological concepts to the bedside

The management of breast cancer has changed dramatically over the past 20 years. Based on gene expression profiles, or proteomics of three or four biomarkers, it is apparent that there are multiple subtypes with different clinical characteristics, clinical courses, and sensitivities to existing therapies. This manuscript reviews the management of hormone receptor-positive, human epidermal growth factor receptor 2-positive, and triple-negative breast cancers, emphasizing changes that have occurred in recent years and focusing on potential mechanisms of drug resistance. I also highlight strategies to prevent or overcome resistance to specific therapeutic agents. As a result of enhanced biological understanding of the molecular anomalies that drive the development, progression, and dissemination of breast cancer, a number of novel, molecularly targeted agents have been added to standard therapies. Chemotherapy, endocrine therapy, and targeted treatments have markedly reduced the risk for recurrence and mortality after primary treatment of breast cancer and have increased the 5- and 10-year survival rates. The challenges with novel therapeutics include the absence of accurate predictive biomarkers to identify those patient who will derive substantial benefit and those patients whose tumors are resistant to specific antitumor agents. As we move forward with increasing molecular segmentation of breast cancer and develop new, highly targeted agents, molecular diagnostics must accompany molecular therapeutics to implement the concept of personalized cancer therapy.

Pharmacologic inhibition of mTOR antagonizes the cytotoxic activity of pemetrexed in non-small cell lung cancer

PURPOSE

Pemetrexed, an inhibitor of thymidylate synthase (TS) and additional folate-dependent enzymes, is clinically active in patients suffering from "non-squamous" non-small cell lung cancer (NSCLC). High expression of TS has been implied as biomarker predictive of resistance to pemetrexed. Against this background, we studied whether inhibition of mTOR could lower expression of TS and thus sensitize NSCLC cells to pemetrexed.

METHODS AND RESULTS

Using squamous cell carcinoma and adenocarcinoma NSCLC cell lines, we observed that constitutive TS expression levels failed to correlate with sensitivity to growth inhibition or apoptosis imposed by pemetrexed in vitro. Interestingly, pemetrexed strongly induced TS RNA and protein expression in all cell lines. The allosteric "rapalogue" mTOR inhibitor everolimus suppressed constitutive, but not pemetrexed-induced TS expression. Surprisingly, cotreatment with everolimus protected NSCLC cells against pemetrexed-induced apoptosis. This resulted in increased long-term clonogenic survival of NSCLC cells treated with pemetrexed plus everolimus as compared to pemetrexed alone. No such negative interaction was observed when everolimus was combined with recombinant TRAIL, a proliferation-independent proapoptotic agent.

CONCLUSIONS

Rapalogues may suppress the antitumor activity of pemetrexed by slowing cell cycle progression. This should be considered when combining pemetrexed and mTOR inhibitors in NSCLC treatment.

HER2 as a Prognostic Marker in Gastric Cancer - A Systematic Analysis of Data from the Literature

Through the recent conduct of the ToGA trial, HER2 has shown to be predictive for the treatment with trastuzumab in advanced gastric and gastro-oesophageal cancer. When it comes to the prognostic properties the situation is different. Despite the fact that it is more than 20 years ago since the first studies demonstrating an association between a positive HER2 status and poor prognosis were published the issue is still controversial. In this current systematic review a large number of studies on HER2 and gastric cancer have been reviewed. The studies included in this review should fulfill the following two criteria. First criterion: The number of patients in each study should be ≥ 100, and the HER2 status should have been determined either by immunohistochemistry (IHC) or in situ hybridization (ISH). Second criterion: The selected articles should include an analysis of the association between the HER2 status and survival or relevant clinicopathological characteristics. Forty-two publications with a total of 12,749 patients fulfilled the two criteria and were reviewed in detail. The majority of the publications (71%) showed that a HER2-postive status measured either by IHC or ISH was associated with poor survival and/or clinicopathological characteristics, such as serosal invasion, lymph node metastases, disease stage, or distant metastases. Based on the current analysis a clear trend towards a potential role for HER2 as a negative prognostics factor in gastric cancer was shown, suggesting that HER2 overexpression and/or amplification is a molecular abnormality that might be linked to the development of gastric cancer.

Sequence variants and haplotype analysis of cat ERBB2 gene: a survey on spontaneous cat mammary neoplastic and non-neoplastic lesions

The human ERBB2 proto-oncogene is widely considered a key gene involved in human breast cancer onset and progression. Among spontaneous tumors, mammary tumors are the most frequent cause of cancer death in cats and second most frequent in humans. In fact, naturally occurring tumors in domestic animals, more particularly cat mammary tumors, have been proposed as a good model for human breast cancer, but critical genetic and molecular information is still scarce. The aims of this study include the analysis of the cat ERBB2 gene partial sequences (between exon 17 and 20) in order to characterize a normal and a mammary lesion heterogeneous populations. Cat genomic DNA was extracted from normal frozen samples (n = 16) and from frozen and formalin-fixed paraffin-embedded mammary lesion samples (n = 41). We amplified and sequenced two cat ERBB2 DNA fragments comprising exons 17 to 20. It was possible to identify five sequence variants and six haplotypes in the total population. Two sequence variants and two haplotypes show to be specific for cat mammary tumor samples. Bioinformatics analysis predicts that four of the sequence variants can produce alternative transcripts or activate cryptic splicing sites. Also, a possible association was identified between clinicopathological traits and the variant haplotypes. As far as we know, this is the first attempt to examine ERBB2 genetic variations in cat mammary genome and its possible association with the onset and progression of cat mammary tumors. The demonstration of a possible association between primary tumor size (one of the two most important prognostic factors) and the number of masses with the cat ERBB2 variant haplotypes reveal the importance of the analysis of this gene in veterinary medicine.

Clinical relevance of ErbB-2/HER2 nuclear expression in breast cancer

Background

The biological relevance of nuclear ErbB-2/HER2 (NuclErbB-2) presence in breast tumors remains unexplored. In this study we assessed the clinical significance of ErbB-2 nuclear localization in primary invasive breast cancer. The reporting recommendations for tumor marker prognostic studies (REMARK) guidelines were used as reference.

Methods

Tissue microarrays from a cohort of 273 primary invasive breast carcinomas from women living in Chile, a Latin American country, were examined for membrane (MembErbB-2) and NuclErbB-2 expression by an immunofluorescence (IF) protocol we developed. ErbB-2 expression was also evaluated by immunohistochemistry (IHC) with a series of antibodies. Correlation between NuclErbB-2 and MembErbB-2, and between NuclErbB-2 and clinicopathological characteristics of tumors was studied. The prognostic value of NuclErbB-2 in overall survival (OS) was evaluated using Kaplan-Meier method, and Cox model was used to explore NuclErbB-2 as independent prognostic factor for OS.

Results

The IF protocol we developed showed significantly higher sensitivity for detection of NuclErbB-2 than IHC procedures, while its specificity and sensitivity to detect MembErbB-2 were comparable to those of IHC procedures. We found 33.6% NuclErbB-2 positivity, 14.2% MembErbB-2 overexpression by IF, and 13.0% MembErbB-2 prevalence by IHC in our cohort. We identified NuclErbB-2 positivity as a significant independent predictor of worse OS in patients with MembErbB-2 overexpression. NuclErbB-2 was also a biomarker of lower OS in tumors that overexpress MembErbB-2 and lack steroid hormone receptors.

Conclusions

We revealed a novel role for NuclErbB-2 as an independent prognostic factor of poor clinical outcome in MembErbB-2-positive breast tumors. Our work indicates that patients presenting NuclErbB-2 may need new therapeutic strategies involving specific blockage of ErbB-2 nuclear migration.

Dual color chromogenic in situ hybridization for determination of HER2 status in breast cancer: a large comparative study to current state of the art fluorescence in situ hybridization

Background

Chromogenic in situ hybridization (CISH) is fast becoming a well established technique for easy and sensitive determination of HER2 gene status in breast cancer. However, for the chromogenic method to achieve status as a safe and reliable technique, the method needs to be validated against already known and validated FISH techniques.

Methods

Here it is reported from a comparative study where HER2 gene status obtained by HER2 CISH pharmDx™ Kit was compared to HER2 gene status obtained by the FDA approved HER2 FISH pharmDx™ Kit and the PathVysion HER-2 DNA probe Kit. The study included 365 formalin fixed and paraffin-embedded invasive breast cancer tissue specimens collected consecutively at a US reference laboratory.

Results

The data obtained revealed an overall HER2 status concordance of approximately 98% for comparisons of HER2 CISH pharmDx™ Kit to both HER2 FISH pharmDx™ Kit and PathVysion HER-2 DNA Probe Kit.

Conclusions

The concordance between results obtained using the recently FDA approved HER2 CISH pharmDx™ Kit with previously FDA approved FISH techniques for HER2 gene status determination indicate that the HER2 CISH pharmDx™ Kit is a reliable chromogenic alternative to fluorescence-based methods.

What is the best choice of partner chemotherapy with trastuzumab for metastatic breast cancer?

The HER2 gene and its role in pathogenicity in human breast cancer were detected in the 1980s. Trastuzumab is a monoclonal antibody directed against the HER2 membrane receptor. The aim of this article is to describe chemotherapy-trastuzumab combinations that have been evaluated in patients with HER2-positive metastatic breast cancer, and to define the possible standards and options.

The role of gene expression profiling in drug discovery

Monitoring gene expression through the dual approaches of transcriptomics (RNA profiling) and proteomics (protein profiling) has become a key component in our efforts to understand complex biological processes. From the molecular stratification of disease states and the selection of potential drug targets, to patient selection and the confirmation of engagement of pharmacology in clinical studies, we are seeing the impact of gene expression profiling across all phases of the drug discovery process. Ongoing technological advances have driven an expansion in the use of these techniques, demonstrated utility in preclinical and clinical settings and increased regulatory and clinical acceptance. As technologies continue to advance apace, gene expression profiling is likely to play an increasingly important role in the future development of drug discovery.

Basal/HER2 breast carcinomas: integrating molecular taxonomy with cancer stem cell dynamics to predict primary resistance to trastuzumab (Herceptin)

High rates of inherent primary resistance to the humanized monoclonal antibody trastuzumab (Herceptin) are frequent among HER2 gene-amplified breast carcinomas in both metastatic and adjuvant settings. The clinical efficacy of trastuzumab is highly correlated with its ability to specifically and efficiently target HER2-driven populations of breast cancer stem cells (CSCs). Intriguingly, many of the possible mechanisms by which cancer cells escape trastuzumab involve many of the same biomarkers that have been implicated in the biology of CS-like tumor-initiating cells. In the traditional, one-way hierarchy of CSCs in which all cancer cells descend from special self-renewing CSCs, HER2-positive CSCs can occur solely by self-renewal. Therefore, by targeting CSC self-renewal and resistance, trastuzumab is expected to induce tumor shrinkage and further reduce breast cancer recurrence rates when used alongside traditional therapies. In a new, alternate model, more differentiated non-stem cancer cells can revert to trastuzumab-refractory, CS-like cells via the activation of intrinsic or microenvironmental paths-to-stemness, such as the epithelial-to-mesenchymal transition (EMT). Alternatively, stochastic transitions of trastuzumab-responsive CSCs might also give rise to non-CSC cellular states that lack major attributes of CSCs and, therefore, can remain "hidden" from trastuzumab activity. Here, we hypothesize that a better understanding of the CSC/non-CSC social structure within HER2-overexpressing breast carcinomas is critical for trastuzumab-based treatment decisions in the clinic. First, we decipher the biological significance of CSC features and the EMT on the molecular effects and efficacy of trastuzumab in HER2-positive breast cancer cells. Second, we reinterpret the genetic heterogeneity that differentiates trastuzumab-responders from non-responders in terms of CSC cellular states. Finally, we propose that novel predictive approaches aimed at better forecasting early tumor responses to trastuzumab should identify biological determinants that causally underlie the intrinsic flexibility of HER2-positive CSCs to "enter" into or "exit" from trastuzumab-sensitive states. An accurate integration of CSC cellular states and EMT-related biomarkers with the currently available breast cancer molecular taxonomy may significantly improve our ability to make a priori decisions about whether patients belonging to HER2 subtypes differentially enriched with a "mesenchymal transition signature" (e.g., luminal/HER2 vs. basal/HER2) would distinctly benefit from trastuzumab-based therapy ab initio.

Pertuzumab plus trastuzumab plus docetaxel for metastatic breast cancer

BACKGROUND

The anti-human epidermal growth factor receptor 2 (HER2) humanized monoclonal antibody trastuzumab improves the outcome in patients with HER2-positive metastatic breast cancer. However, most cases of advanced disease eventually progress. Pertuzumab, an anti-HER2 humanized monoclonal antibody that inhibits receptor dimerization, has a mechanism of action that is complementary to that of trastuzumab, and combination therapy with the two antibodies has shown promising activity and an acceptable safety profile in phase 2 studies involving patients with HER2-positive breast cancer.

METHODS

We randomly assigned 808 patients with HER2-positive metastatic breast cancer to receive placebo plus trastuzumab plus docetaxel (control group) or pertuzumab plus trastuzumab plus docetaxel (pertuzumab group) as first-line treatment until the time of disease progression or the development of toxic effects that could not be effectively managed. The primary end point was independently assessed progression-free survival. Secondary end points included overall survival, progression-free survival as assessed by the investigator, the objective response rate, and safety.

RESULTS

The median progression-free survival was 12.4 months in the control group, as compared with 18.5 months in the pertuzumab group (hazard ratio for progression or death, 0.62; 95% confidence interval, 0.51 to 0.75; P<0.001). The interim analysis of overall survival showed a strong trend in favor of pertuzumab plus trastuzumab plus docetaxel. The safety profile was generally similar in the two groups, with no increase in left ventricular systolic dysfunction; the rates of febrile neutropenia and diarrhea of grade 3 or above were higher in the pertuzumab group than in the control group.

CONCLUSIONS

The combination of pertuzumab plus trastuzumab plus docetaxel, as compared with placebo plus trastuzumab plus docetaxel, when used as first-line treatment for HER2-positive metastatic breast cancer, significantly prolonged progression-free survival, with no increase in cardiac toxic effects. (Funded by F. Hoffmann-La Roche/Genentech; ClinicalTrials.gov number, NCT00567190.).

HER2 and TOP2A in high-risk early breast cancer patients treated with adjuvant epirubicin-based dose-dense sequential chemotherapy

Background

HER2 and TOP2A parameters (gene status, mRNA and protein expression) have individually been associated with the outcome of patients treated with anthracyclines. The aim of this study was to comprehensively evaluate the prognostic/predictive significance of the above parameters in early, high-risk breast cancer patients treated with epirubicin-based, dose-dense sequential adjuvant chemotherapy.

Methods

In a series of 352 breast carcinoma tissues from patients that had been post-operatively treated with epirubicin-CMF with or without paclitaxel, we assessed HER2 and TOP2A gene status (chromogenic in situ hybridization), mRNA expression (quantitative reverse transcription PCR), as well as HER2 and TopoIIa protein expression (immunohistochemistry).

Results

HER2 and TOP2A amplification did not share the same effects on their downstream molecules, with consistent patterns observed in HER2 mRNA and protein expression according to HER2 amplification (all parameters strongly inter-related, p values < 0.001), but inconsistent patterns in the case of TOP2A. TOP2A gene amplification (7% of all cases) was not related to TOP2A mRNA and TopoIIa protein expression, while TOP2A mRNA and TopoIIa protein were strongly related to each other (p < 0.001). Hence, TOP2A amplified tumors did not correspond to tumors with high TOP2A mRNA or TopoIIa protein expression, while the latter were characterized by high Ki67 scores (p = 0.003 and p < 0.001, respectively). Multivariate analysis adjusted for nodal involvement, hormone receptor status, Ki67 score and HER2/TOP2A parameters revealed HER2/TOP2A co-amplification (21.2% of HER2 amplified tumors) as an independent favorable prognostic factor for DFS (HR = 0.13, 95% CI: 0.02-0.96, p = 0.046); in contrast, increased HER2/TOP2A mRNA co-expression was identified as an independent adverse prognostic factor for both DFS (HR = 2.41, 95% CI: 1.31-4.42, p = 0.005) and OS (HR = 2.83, 95% CI: 1.42-5.63, p = 0.003), while high TOP2A mRNA expression was an independent adverse prognostic factor for OS (HR = 2.06, 95% CI: 1.23-3.46, p = 0.006). None of the parameters tested was associated with response to paclitaxel.

Conclusions

This study confirms the favorable prognostic value of HER2/TOP2A co-amplification and the adverse prognostic value of high TOP2A mRNA expression extending it to the adjuvant treatment setting in early high-risk breast cancer. The strong adverse prognostic impact of high HER2/TOP2A mRNA co-expression needs further validation in studies designed to evaluate markers predictive for anthracyclines.

Trial registration

Australian New Zealand Clinical Trials Registry ACTRN12611000506998.

RNA interference-directed silencing of VPAC1 receptor inhibits VIP effects on both EGFR and HER2 transactivation and VEGF secretion in human breast cancer cells

We used small-interference RNA (siRNA) to explore the mechanisms of some vasoactive intestinal peptide (VIP) actions on human breast cancer cells. Transfection of estrogen-dependent (T47D) and estrogen-independent (MDA-MB-468) breast cancer cells with VPAC(1)-receptor siRNA completely abolished VIP stimulatory effect on secretion of the main angiogenic factor, vascular endothelial growth factor (VEGF), and transactivation of epidermal growth factor receptor (EGFR or HER1) and HER2, two members of HER family of tyrosine-kinase receptors. The silencing procedure suggested the involvement of EGFR and HER2 transactivation in VIP-stimulated VEGF secretion. It was further supported by blocking tyrosine kinase activity by the selective HER inhibitors AG-1478 (EGFR) and AG-825 (HER2). Results give value to the specific signaling of VIP through VPAC(1) receptor in human breast cancer cells and support the potential use of VPAC(1)-receptor antagonists in combined targeted therapies for breast cancer. Molecular therapies involving RNA interference of VPAC(1)-receptor expression could also be considered.

Silver-Enhanced In Situ Hybridization as an Alternative to Fluorescence In Situ Hybridization for Assaying HER2 Amplification in Clinical Breast Cancer

Purpose

Valid determination of HER2 status is a prerequisite to establish an adequate treatment strategy for breast cancer patients, regardless of the disease stage. The goal of this study was to examine the feasibility of the newly developed silver-enhanced in situ hybridization (SISH) technique as an alternative to fluorescence in situ hybridization (FISH) for HER2 assay in primary invasive breast cancer.

Methods

FISH and SISH for HER2 amplification were performed using tissue microarray. Both methods were used in 257 consecutive primary breast cancers.

Results

HER2 amplification was observed in 62 (23.1%) of a total of 257 breast cancers based on SISH. Of the 257 breast cancers measured using both methods, the results of the two methods were consistent in 248 (concordance, 96.5%; kappa=0.903). When we compared HER2 amplification in the primary tumor with the metastatic lymph nodes of the same patients, HER2 amplification was observed in nine cases (14.0%) out of 64 cases in which HER2 was not amplified in the primary tumors. In contrast, HER2 status was completely preserved in metastatic lymph nodes showing HER2 amplification in the primary tumor.

Conclusion

These results indicate that SISH can be a feasible alternative to FISH in the clinical setting. In node-positive breast cancer, confirmation of the HER2 status of the metastatic lymph nodes appears to be mandatory, regardless of the HER2 status of the primary tumors.

Shared molecular targets in pediatric gliomas and ependymomas

BACKGROUND

Recent advances in multidisciplinary treatment approaches have improved the overall prognosis of pediatric brain tumors, but some patients remain refractory to treatment and do poorly. Several molecularly targeted therapies are under development for the treatment of brain tumors, and high-grade gliomas in adults are a particular area of study.

PROCEDURE

To better understand if these new therapies can be used in pediatric populations, we examined the expression of the following seven marker genes involved in signaling pathways targeted by new therapies: β-catenin, suppressor of fused (SUFU), erythroblastic leukemia viral oncogene homolog (ERBB) 2, platelet-derived growth factor receptorα (PDGFRα), proliferating cell nuclear antigen (PCNA), secreted protein acid and rich in cysteine (SPARC), and granulocyte colony-stimulating factor receptor (G-CSFR). Samples from 27 patients with the primitive neuroectodermal tumor (PNET)/medulloblastomas (MBs) (n = 8), ependymomas (n = 5), or gliomas (n = 14) were assessed by quantitative real-time PCR. [Correction made here after initial online publication]. We assigned an EXP score to compare across samples and determined the levels of gene expression among tumor cell types.

RESULTS

Gene expression varied among the different tumors, but, within a tumor type, clear expression patterns were seen. The expression of SUFU, ERBB2, and PCNA in metastatic MBs were greater than that seen in non-metastatic MBs. Most glioma cases highly expressed PDGFRα and G-CSFR. Additionally, the expression patterns of gliomas and ependymomas were similar (r = 0.77, P = 0.04), but PNET/MBs substantially differed from gliomas (r = -0.37, P = 0.41) or ependymomas (r = 0.23, P = 0.62).

CONCLUSIONS

The development of new drugs targeting up-regulated pathways may be useful for the treatment of pediatric brain tumors. As new drugs are developed, gliomas and ependymomas may be treated with similar compounds.