Showing papers on "HER2/neu published in 2007"

Descriptive analysis of estrogen receptor (ER)-negative, progesterone receptor (PR)-negative, and HER2-negative invasive breast cancer, the so-called triple-negative phenotype: a population-based study from the California cancer Registry.

Abstract: BACKGROUND. Tumor markers are becoming increasingly important in breast cancer research because of their impact on prognosis, treatment, and survival, and because of their relation to breast cancer subtypes. The triple-negative phenotype is important because of its relation to the basal-like subtype of breast cancer. METHODS. Using the population-based California Cancer Registry data, we identified women diagnosed with triple-negative breast cancer between 1999 and 2003. We examined differences between triple-negative breast cancers compared with other breast cancers in relation to age, race/ethnicity, socioeconomic status (SES), stage at diagnosis, tumor grade, and relative survival. RESULTS. A total of 6370 women were identified as having triple-negative breast cancer and were compared with the 44,704 women with other breast cancers. Women with triple-negative breast cancers were significantly more likely to be under age 40 (odds ratio [OR], 1.53), and non-Hispanic black (OR, 1.77) or Hispanic (OR, 1.23). Regardless of stage at diagnosis, women with triple-negative breast cancers had poorer survival than those with other breast cancers, and non-Hispanic black women with late-stage triple-negative cancer had the poorest survival, with a 5-year relative survival of only 14%. CONCLUSIONS. Triple-negative breast cancers affect younger, non-Hispanic black and Hispanic women in areas of low SES. The tumors were diagnosed at later stage and were more aggressive, and these women had poorer survival regardless of stage. In addition, non-Hispanic black women with late-stage triple-negative breast cancer had the poorest survival of any comparable group. Cancer 2007. © 2007 American Cancer Society.

Protein-tyrosine phosphatase 1B is required for HER2/Neu-induced breast cancer.

Abstract: The protein-tyrosine phosphatase 1B (PTP1B; PTPN1) is an important regulator of mammalian metabolism and also helps control signaling by growth factors, cytokines, and extracellular matrix. Gene knockout studies in mice established PTP1B as a key negative regulator of the insulin and leptin receptors. Experiments using PTP1B−/− fibroblast lines, dominant-negative mutants, or small interfering RNAs indicate that PTP1B contributes to dephosphorylation of the epidermal growth factor receptor and platelet-derived growth factor receptors as well. However, PTP1B also may have some positive (signal enhancing) roles downstream of some growth factor receptors and integrins. Previous studies indicated that PTP1B is overexpressed in a significant subset of breast and ovarian cancers, especially in those overexpressing HER2/Neu (HER2+ tumors). However, experiments using tissue culture cells yield conflicting results on the effects of PTP1B in HER2 signaling, leaving the consequences of PTP1B overexpression for breast carcinogenesis unclear. To determine how PTP1B deficiency affects HER2-evoked breast tumorigenesis, we generated mouse mammary tumor virus (MMTV)–NeuNT transgenic mice lacking one or both alleles of PTP1B. Although heterozygous loss of PTP1B has no effect on tumorigenesis, homozygous PTP1B deficiency dramatically delays or prevents the onset of MMTV-NeuNT–evoked breast tumors. The effects of PTP1B deficiency correlate with defective extracellular signal-regulated kinase activation in preneoplastic mammary glands from compound mutant mice. In contrast, PTP1B deficiency has no effect on MMTV-polyoma middle T tumorigenesis. Our data raise the possibility that PTP1B inhibitors may be chemopreventative for some forms of breast cancer. [Cancer Res 2007;67(6):2420–4]

111 In-Labeled Trastuzumab (Herceptin) Modified with Nuclear Localization Sequences (NLS): An Auger Electron-Emitting Radiotherapeutic Agent for HER2/neu-Amplified Breast Cancer

Abstract: The cytotoxicity and tumor-targeting properties of the anti-HER2/neu monoclonal antibody trastuzumab modified with peptides (CGYGPKKKRKVGG) harboring the nuclear localization sequence ([NLS] italicized) of simian virus 40 large T-antigen and radiolabeled with 111In were evaluated. Methods: Trastuzumab was derivatized with sulfosuccinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate (sulfo-SMCC) for reaction with NLS-peptides and labeled with 111In using diethylenetriaminepentaacetic acid (DTPA). The immunoreactivity of 111In-NLS-trastuzumab was determined by its ability to displace the binding of trastuzumab to SK-BR-3 human breast cancer (BC) cells. Cellular uptake and nuclear localization were evaluated in SK-BR-3, MDA-MB-361, and MDA-MB-231 BC cells, expressing high, intermediate, or very low levels of HER2/neu, respectively, by cell fractionation and confocal microscopy. Biodistribution and nuclear uptake were compared in athymic mice bearing MDA-MB-361 xenografts. The cytotoxicity of 111In-trastuzumab and 111In-NLS-trastuzumab was studied by clonogenic assays, and DNA damage was assessed by probing for phosphorylated histone H2AX (γH2AX) foci. Results: The dissociation constant for binding of 111In-NLS-trastuzumab to SK-BR-3 cells was reduced

Identification of tumorsphere- and tumor-initiating cells in HER2/Neu-induced mammary tumors.

Abstract: A variety of human malignancies, including breast cancer, are thought to be organized in a hierarchy, whereby a relatively minor population of tumor initiating cells (TIC) is responsible for tumor growth and the vast majority of remaining cells is nontumorigenic. Analysis of TICs in model systems of breast cancer would offer uniform and accessible source of tumor cells and the power of mouse genetics to dissect these rare cells. The HER2/Neu proto-oncogene is overexpressed in an aggressive form of human breast cancer. Mouse mammary tumor virus (MMTV)-Neu transgenic mice develop mammary tumors that mimic human HER2 subtype breast cancer. Here, we report on the functional identification of mouse HER2/Neu TICs that can induce tumors after transplantation into the mammary gland of recipient mice. Secondary tumors formed after injecting MMTV-Neu TICs resemble primary tumors in the original transgenic mice and are organized in a hierarchy containing TICs as well as their nontumorigenic descendants. To study MMTV-Neu TICs in vitro, we grew tumorspheres under nonadherent culture conditions. Tumorsphere forming units (TFU) capable of producing tumorspheres retained tumorigenic potential and were indistinguishable by several criteria from TICs. Interestingly, MMTV-Neu TICs and TFUs were committed to the luminal cell fate when induced to differentiate in vitro. Our data define reproducible characteristics of the MMTV-Neu TIC and TFU, which help to explain marker expression profiles of HER2-positive breast cancer. In addition, the similarity between TICs and TFUs in this system provides a rationale for TFU-based screens to target tumor-initiating cells in HER2(+) breast cancer.

HER2/neu role in breast cancer: from a prognostic foe to a predictive friend.

Abstract: Purpose of review The principal effort of this review was to elucidate the role of human epidermal growth factor receptor 2/neu expression in breast cancer, either as an independent prognostic factor or a predictive marker of response to antineoplastic therapy, in light of the most recent results obtained with the use of trastuzumab, in either the metastatic or the adjuvant setting. Recent findings Human epidermal growth factor receptor 2-overexpressing breast cancer is known to be associated with particularly aggressive disease and poor prognosis. On the other hand, human epidermal growth factor receptor 2/neu overexpression may predict response to endocrine therapy or chemotherapy. Nevertheless, trastuzumab increases the clinical benefit of first-line chemotherapy in patients with metastatic breast cancers that overexpress human epidermal growth factor receptor 2. Decades of randomized clinical trials on the front-line treatment of metastatic breast cancer have never been able to show so remarkable differences in survival as recent randomized trials comparing chemotherapy with chemotherapy plus trastuzumab in women with human epidermal growth factor receptor 2-overexpressing metastatic breast cancer have been able to do. Summary In the pretrastuzumab era, retrospective analyses have shown that human epidermal growth factor receptor 2 overexpression is an adverse prognostic factor associated with an increased risk of disease recurrence and death. In the trastuzumab era, this drug has changed the natural history of human epidermal growth factor receptor 2-positive breast cancer, either in the metastatic or, according to the most recent evidences, in the adjuvant setting.

Amplification and Overexpression of HER2/neu Gene and HER2/neu Protein in Salivary Duct Carcinoma of the Parotid Gland

Abstract: Objectives To detect amplification of the HER2/neu gene by means of fluorescence in situ hybridization (FISH) in a series of 13 salivary duct carcinomas (SDCs) and to compare the results with immunohistochemical (IHC) assessment of HER2/neu protein expression. Design Retrospective analysis. Setting Department of Pathology, University of Brescia. Patients We studied 13 cases of SDC diagnosed between January 1, 1997, and June 30, 2004, all arising from the parotid gland. Twelve patients were treated with surgery and radiotherapy, and 1 patient received only palliative radiotherapy. Seven patients died of disease, 3 patients were alive with disease, and 3 were free of disease. Main Outcome Measures HER2/neu protein expression and HER2/neu gene amplification detected by means of IHC assessment and FISH, respectively. Results With IHC assessment, 10 cases showed overexpression (grade 3+) of HER2/neu protein, whereas 3 cases were negative for this protein (grade 0/1+). Using FISH, amplification of the HER2/neu gene was found in 8 of the 10 grade 3+ cases, whereas none of the cases negative for the protein according to IHC assessment had amplification of the gene. Because of the small number of patients, it was not possible to statistically correlate HER2/neu protein expression or HER2/neu gene amplification and survival. Conclusion Our data demonstrate that HER2/neu protein is frequently overexpressed in SDC, and in contrast to previous reports, overexpression of the protein is associated in most cases with HER2/neu gene amplification.

Intratumoral heterogeneity of HER2/neu in breast cancer--a rare event.

Abstract: HER2/neu is overexpressed in about 20% of invasive breast carcinomas. Numerous studies have shown that there is high level of concordance between the HER2/neu status of the primary breast cancer and the metastases of a given patient. Recently, changes in HER2/neu status with tumor progression have been reported, suggesting the possibility of an emerging different tumor clone. Little is known about intratumoral heterogeneity with regard to HER2/neu oncoprotein overexpression. We identified nine cases of invasive ductal carcinoma that showed intratumoral variation in HER2/neu oncoprotein expression by immunohistochemistry. This was confirmed by the intratumoral variation in the amplification status of the HER2/neu gene by fluorescence in situ hybridization and by chromogenic in situ hybridization. The results of this study suggest that some cases of primary breast carcinoma are heterogeneous in regard to HER2/neu gene amplification or protein overexpression. Heterogeneity of HER2/neu status in a tumor may be a rare event or underestimated. This phenomenon should be examined as it may contribute to a better understanding of the variation in therapeutic responses and the conflicting data in studies about the prognostic and predictive role of HER2/neu status in subsets of breast cancer patients.

In ovarian cancer the prognostic influence of HER2/neu is not dependent on the CXCR4/SDF-1 signalling pathway

Abstract: HER2/neu overexpression is a driving force in the carcinogenesis of several human cancers. In breast cancer the prognostic influence of HER2/neu was shown to be at least partly based on increased metastatic potential mediated by the chemokine–chemokine receptor pair SDF-1(CXCL12)/CXCR4. We wanted to evaluate the influence of HER2/neu on ovarian cancer prognosis and to investigate whether compromised survival would correlate with CXCR4 expression and/or SDF-1 abundance. Therefore, we analysed HER2/neu, CXCR4, and SDF-1 in 148 ovarian tumour samples by means of immunohistochemistry on tissue microarrays. Overexpression of HER2/neu was found in 27.6% of ovarian cancer tissues and in 15% of ovarian borderline tumours. In ovarian cancer patients, overexpression of HER2/neu correlated closely with overall survival (univariate hazard ratio (HR) 2.59, P=0.005; multiple corrected HR 1.92, P=0.074). In contrast, CXCR4 expression and SDF-1 abundance had no impact on overall survival, and both parameters were not correlated with HER2/neu expression. As expected, cytoplasmic CXCR4 expression and SDF-1 abundance correlated closely (P<0.0001). Our results confirm a univariate influence of HER2/neu expression on overall survival, which was completely independent of the expression of CXCR4 and the abundance of SDF-1, implying significant differences between the HER2/neu downstream pathways in ovarian cancer compared with breast cancer.

Alterations in the expression of PDCD4 in ductal carcinoma of the breast.

Abstract: Programmed cell death 4 gene (PDCD4), an in vivo repressor of transformation, was originally isolated from a human glioma library by screening it with an antibody against a nuclear antigen in proliferating cells. PDCD4 functions as a transformation repressor by inhibiting the activity of the RNA helicase, eIF4A. We previously showed that retinoids, anti-estrogens and HER2/neu antagonist induce PDCD4 expression in human breast cancer cell lines. Very little is known about the expression of PDCD4 in human breast cancer tissues or the significance of the PDCD4 expression in breast cancer. To gain insight into the pattern of the PDCD4 expression in breast tissues, we performed an immunohistochemical analysis of the PDCD4 expression in 80 archived, normal and ductal breast carcinoma tissues (invasive and carcinoma in situ) (DCIS) and correlated PDCD4 expression with expression of known prognostic markers in breast cancer (ER, PR and HER2/neu). To assess the role of methylation on PDCD4 expression in breast cancer cells, breast cancer cell lines were treated with the demethylating agent 5-deoxy-azacytidine and analyzed for PDCD4 expression. We observed primarily nuclear localization of PDCD4 in ductal carcinoma in situ compared to normal breast tissues where the PDCD4 expression was predominantly cytoplasmic. This was seen more frequently in DCIS cases that were ER positive and HER2/neu negative samples. PDCD4 expression was markedly decreased in the invasive ductal carcinoma. We did not observe any significant relationship between PDCD4 expression and the expression of RAR or PR. In T-47D, MDA-MB-435 and MDA-MB-231 cells, treatment with 5-deoxy-azacytidine did not result in an increased expression of PDCD4. The present study demonstrated altered cellular localization of PDCD4 when comparing normal breast to neoplastic breast tissues. In addition, there was a decreased expression of PDCD4 in breast cancer when compared with normal breast tissue. A loss of the PDCD4 expression in breast cancer cell lines does not appear to result from hypermethylation of the PDCD4 promoter.

Spectral fluorescence molecular imaging of lung metastases targeting HER2/neu.

Abstract: Purpose: Surgical resection of pulmonary metastases is now a clinically accepted cancer therapy but its success depends on the accurate localization and removal of all tumor foci. To enhance the detection of pulmonary metastases during surgery, we developed an i.v. administered optical probe that uses a monoclonal antibody, Herceptin (trastuzumab), conjugated to a fluorophore, rhodamine green (RhodG), to specifically detect human epidermal growth factor receptor type 2 (HER2/neu)–expressing pulmonary lesions in an animal model of lung metastases. Experimental Design: Pulmonary metastases were induced by i.v. injection of gene-transfected murine embryonic fibroblasts (3T3) cells in a murine model to produce a mixed population of HER2+ and HER2− tumors. To image these tumors, an anti-HER2 (Herceptin) or a control (HUT) complementarity-determining region–grafted antibody was conjugated to RhodG and injected i.v. into mice. Spectral fluorescence imaging was done after thoracotomy and images were correlated with gross and microscopic pathology to assess sensitivity and specificity. Results: HER2+ tumors injected with Herceptin-RhodG were more fluorescent than either HER2− tumors or HER2+ tumors injected with HUT-RhodG at all time points. The maximal fluorescence signal in HER2+ tumors injected with Herceptin-RhodG was observed at 1 day postinjection. The tumors fluoresced primarily at the rim and not their center, reflecting the binding-site barrier that is commonly seen with high-affinity antibodies. Conclusion: A HER2-targeted optical imaging probe shows the ability to specifically enhance HER2+ pulmonary metastases but not HER2− pulmonary metastases. The high sensitivity and specificity of this probe is encouraging for the development of antigen-targeted optical probes to assist in the resection of pulmonary metastases.

Updated recommendations from the Canadian National Consensus Meeting on HER2/neu testing in breast cancer.

Abstract: Testing for her2/neu in breast cancer at the time of primary diagnosis is now the standard of care. Accurate and standardized testing methods are of prime importance to ensure the proper classification of the patient’s her2/neu status. A meeting of pathologists from across Canada was convened to update the Canadian her2/neu testing guidelines. This National her2/neu Testing Committee reviewed the recently published American Society of Clinical Oncology/ College of American Pathologists (asco/cap) guidelines for her2/neu testing in breast cancer. The updated Canadian her2/neu testing guidelines are based primarily on the asco/cap guidelines, with some modifications. It is anticipated that widespread adoption of these guidelines will further improve the accuracy of her2/neu testing in Canada.

Phase II of trastuzumab and cisplatin in patients (pts) with advanced gastric cancer (AGC) with HER2/neu overexpression/amplification

Abstract: 4613 Background: Trastuzumab(T) exhibits activity in human gastric cancer cells that overexpress HER2/neu. We previously reported a 13.5% HER2/neu overexpression/amplification in AGC or gastroesofageal junction (GEJ) cancers (Gravalos C, et al. J Clin Oncol 24, 18S, 200s, abstr # 4089). We designed a phase II trial to determine the efficacy and tolerability of T and cisplatin(C) in pts with ACG with HER2/neu overexpression/amplification. Exploratory objectives include analysis of c-erbB-2 extracellular domain and correlation of the results with histological erB-2/neu overexpression and with clinical response Methods: Chemo-naive pts with adenocarcinoma histopatologically confirmed, HER2/neu overexpression/amplification, measurable, no operable, locally advanced or metastatic AGC, age ≥ 18, ECOG ≤ 2, FEVI ≥ 50% and adequate organ function were eligible. Prior adjuvant radiotherapy or/and chemotherapy were allowed. Immunohistochemistry (IHC) was performed using herceptest. A fluorescence in situ hybridizati...

Differential expression of c-Met, its ligand HGF/SF and HER2/neu in DCIS and adjacent normal breast tissue.

Abstract: Aims: Tyrosine kinase receptors Her2/neu and c-Met play an important role in breast cancer development and progression. Our aim was to determine the expression of c-Met, its ligand hepatocyte growth factor/scatter factor (HGF/SF) and Her2/neu in ductal carcinoma in situ (DCIS) lesions of the breast (n = 39) by two different immunocytochemical techniques, classical immunohistochemistry and immunofluorescence, and to correlate their expression levels with histopathological and clinical characteristics. Methods and results: Both methods revealed similar c-Met staining patterns in both the in situ component and the adjacent normal tissue (P < 0.001). However, an imbalance in c-Met expression between tumour and surrounding normal tissue was correlated with high-grade DCIS (Van Nuys Grade 3). No correlation existed between Her2/neu and c-Met expression. High HGF/SF immunoreactivity was observed in 43.6% of the cases, yet the adjacent cellular stroma revealed only low levels of HGF/SF. No correlation existed between c-Met, Her2/neu or HGF/SF expression and clinicopathological factors. Conclusion: An imbalance in c-Met expression between tumour and surrounding normal tissue is associated with an aggressive DCIS phenotype. Moreover, c-Met and HGF/SF may contribute to tumour development by different means than those controlled by Her2/neu.

Breast cancer expressing the activated HER2/neu is sensitive to gefitinib in vitro and in vivo and acquires resistance through a novel point mutation in the HER2/neu.

Abstract: The HER2/neu oncogene is an important diagnostic and prognostic factor and therapeutic target in breast and other cancers. We developed and characterized a breast cancer cell line (Bam1a) that overexpresses the activated HER2/neu and ErbB-3 and has a gene expression profile consistent with the ErbB-2 genetic signature. We evaluated the effects of the epidermal growth factor receptor (EGFR)/HER2 inhibitor, gefitinib, on this breast tumor line in vitro and in vivo. We characterized the effects of gefitinib on EGFR, HER2, and ErbB-3 phosphorylation by Western blot and determined the effects on downstream signaling through growth, survival, and stress pathways and the effect on proliferation, cell cycle, and apoptosis. Gefitinib treatment diminished phosphorylation of the ErbB-3 > EGFR > HER2/neu and signal transducers and activators of transcriptions in a dose-dependent fashion. Downstream mitogenic signaling through mitogen-activated protein (MAP)/extracellular signal regulated kinase kinase, p44/42 MAP kinase (MAPK) and stress signaling through c-Jun-NH(2)-kinase (JNK) 1 and c-Jun was impaired (1 micromol/L, 4-24 h), leading to cytostasis and cell cycle arrest within 24 h by decreased cyclin D1, cyclin B1, and p(Ser795)Rb and increased p27. Proliferation and colony formation were inhibited at 0.5 and 1 micromol/L, respectively, and correlated with altered gene expression profiles. Diminished survival signaling through Akt, induction of bim, loss of connexin43, and decreased production of vascular endothelial growth factor-D preceded caspase-3 and poly(ADP)ribose polymerase (PARP) cleavage and apoptosis (>50% 2 micromol/L, 48 h). Oral administration of gefitinib was able to prevent the outgrowth of Bam1a tumor cells from palpable lesions, shrink established tumors, eliminate HER2 and HER3 phosphorylation, and decrease MAPK and Akt signaling in vivo. A variant of the Bam1a cell line, IR-5, with acquired ability to grow in 5 micromol/L gefitinib was developed and characterized. IR-5 bears a novel point mutation in the HER2/neu that corresponds to a L726I in the ATP-binding pocket and correlates with a log decrease in sensitivity to gefitinib, increased heterodimerization with EGFR and HER3, and impaired down-regulation. Gene expression profiling of IR-5 showed increased expression of EMP-1, NOTCH-1, FLT-1, PDGFB, and several other genes that may contribute to the resistant phenotype and sustain signaling through MAPK and Akt. This model will be useful in understanding the differences between intrinsic drug sensitivity and acquired resistance in the context of therapeutic strategies that target oncogene addicted diseases.

Adenovirus 5 vector genetically re-targeted by an Affibody molecule with specificity for tumor antigen HER2/neu.

Abstract: In order to use adenovirus (Ad) type 5 (Ad5) for cancer gene therapy, Ad needs to be de-targeted from its native receptors and re-targeted to a tumor antigen. A limiting factor for this has been to find a ligand that (i) binds a relevant target, (ii) is able to fold correctly in the reducing environment of the cytoplasm and (iii) when incorporated at an optimal position on the virion results in a virus with a low physical particle to plaque-forming units ratio to diminish the viral load to be administered to a future patient. Here, we present a solution to these problems by producing a genetically re-targeted Ad with a tandem repeat of the HER2/neu reactive Affibody molecule (ZH) in the HI-loop of a Coxsackie B virus and Ad receptor (CAR) binding ablated fiber genetically modified to contain sequences for flexible linkers between the ZH and the knob sequences. ZH is an Affibody molecule specific for the extracellular domain of human epidermal growth factor receptor 2 (HER2/neu) that is overexpressed in inter alia breast and ovarian carcinomas. The virus presented here exhibits near wild-type growth characteristics, infects cells via HER2/neu instead of CAR and represents an important step toward the development of genetically re-targeted adenoviruses with clinical relevance.

Role for HER2/neu and HER3 in fulvestrant-resistant breast cancer.

Abstract: Tamoxifen resistance is common for estrogen receptor alpha (ERalpha) positive breast cancer. Second-line therapies include aromatase inhibitors or fulvestrant. We have shown previously that fulvestrant reversed 17beta-estradiol-induced tumor regression of tamoxifen-stimulated MCF-7 xenografts (MCF-7TAMLT) treated for >5 years with tamoxifen in athymic mice and paradoxically stimulated growth. We investigated mechanisms responsible for growth by fulvestrant in the presence of physiologic estradiol and therapeutic strategies in vivo. The results demonstrated that only estradiol increased expression of the estrogen-responsive genes, c-myc, igf-1, cathepsin D, and pS2 mRNAs, in MCF-7E2 and MCF-7TAMLT tumors. Tamoxifen or fulvestrant decreased the estradiol-induced increase of these mRNAs in both tumor models. However, tyrosine-phosphorylated HER2/ neu, HER3, phospho-extracellular-regulated kinase-1/2 (ERK-1/2), and phospho-glycogen synthetase kinase 3alpha (GSK3alpha) and beta proteins were increased in MCF-7TAMLT tumors treated with fulvestrant compared to estradiol, control, or tamoxifen. Phospho-HER2/neu interacted with HER3 protein in MCF-7TAMLT tumors. In order to determine whether the functional interaction of HER2/neu with HER3 is critical for growth of fulvestrant-stimulated MCF-7TAMLT tumors, pertuzumab (an antibody that blocks HER2/neu-HER3 interaction) was used in an in vivo xenograft growth assay. Only growth of fulvestrant-treated MCF-7TAMLT xenografts was decreased significantly by 37.2% in response to pertuzumab (P=0.004). Pertuzumab specifically decreased the interaction of HER2/neu protein with HER3 in fulvestrant-stimulated MCF-7TAMLT tumors. These results suggested growth of MCF-7TAMLT tumors by tamoxifen or fulvestrant is potentially independent of ERalpha transcriptional activity as evidenced by lack of induction of four estrogen-responsive genes. The results suggested that growth of MCF-7TAMLT tumors treated with fulvestrant in the presence of physiologic estradiol is in part mediated through enhanced signaling from the HER2/neu-HER3 pathway as pertuzumab partially inhibited growth and the interaction of HER2/neu with HER3 in vivo.

Treatment of implanted mammary tumors with recombinant vesicular stomatitis virus targeted to Her2/neu.

Abstract: Vesicular stomatitis virus (VSV) is being developed for cancer therapy. We have created a recombinant replicating VSV (rrVSV) that targeted to Her2/neu expressing breast cancer cells and expresses mouse GM-CSF. We now tested the efficacy of this rrVSV in the treatment of peritoneal tumor implants of D2F2/E2 cells, a BALB/c mouse mammary tumor cell line, which was stably transfected to express Her2/neu. Mice were treated 1 day following tumor implantation with either 2 x 10(8) infectious doses rrVSV or conditioned media (CM). All control animals developed massive peritoneal tumor with a median survival of 16 days. Nine of 10 rrVSV treated mice survived long term with no evidence of tumor. rrVSV had much less efficacy in treating implants of the parent D2F2 cells that did not express Her2/neu. The median survival was 13.5 days in mice treated with CM and 21 days in those treated with rrVSV. There was one long term survivor in the rrVSV treated group. None of the rrVSV treated animals showed evidence of viral toxicity. Three of 7 long term survivors did not develop tumor when rechallenged first with D2F2/E2 and then with D2F2 cells. Both successful therapy and resistance to rechallenge were T-cell dependent. These studies demonstrate that targeted rrVSV eliminated peritoneal implants of Her2/neu expressing tumor and elicited an anti-tumor T-cell immunologic response.

Circulating oncoproteins HER2/neu, EGFR and CAIX (MN) as novel cancer biomarkers

Abstract: Pharmaceutical companies have developed targeted therapies such as trastuzumab and lapatinib for human epidermal growth factor receptor (HER)2/neu-positive tumors, while others have developed antiepidermal growth factor receptor (EGFR) therapies, such as tarceva and erbitux for EGFR-positive tumors. A drug called rencarex is targeted to an oncoprotein designated carbonic anhydrase IX (CAIX), which is being evaluated in renal cell carcinoma patients. Based on these targeted therapeutic approaches, this review describes clinical research studies performed with enzyme-linked immunosorbent assays specific for the circulating oncoproteins, HER2/neu, EGFR and CAIX. These circulating biomarkers have the potential to be used in conjunction with the specific targeted therapies for patient selection, monitoring and management. With the variety of new therapeutic options, the major challenge ahead will be to select the appropriate therapy or combinations of therapies for each patient. Specific biomarker tests, either alone or in panels, will be needed at the appropriate time in the course of disease to ensure that patients receive the right drug at the right time. These tests will also be valuable in monitoring the efficacy of the targeted therapies. A circulating biomarker such as serum HER2/neu may be able to specifically identify patients with progressing HER2/neu-positive disease and provide the information needed by physicians to choose from the variety of HER2/neu-targeted therapies that will soon be available to cancer patients.

Expression of p21(Wafl/Cip1), p57(Kip2) and HER2/neu in patients with gallbladder cancer.

Abstract: BACKGROUND To improve the prognosis of gallbladder cancer (GC) patients, a better understanding of the mechanisms of tumor development and progression is essential. The deregulation of cell cycle control is a critical step in the development of cancer. The purpose of this study was to investigate the expression of p21(Wafl/Cip1), p57(Kip2) and HER2/neu in an unselected GC patient population and to assess the association of these markers with p27(Kip1) expression, p53 gene mutation status and clinical parameters of the patients. PATIENTS AND METHODS Formalin-fixed paraffin-embedded tissues from 55 operated GC patients were used to determine the expression of p21(Wafl/Cip1), p57(Kip2) and HER2/neu with immunohistochemistry. RESULTS Expression of p21(Wafl/Cip1) was observed in 28%, of p57(Kip2) in 19% and of HER2/neu in 13% of the patients. Absence of p57(Kip2) expression was significantly associated with T3/T4 stage (p = 0.01), positive lymph nodes (p = 0.02) and advanced UICC stages (p = 0.05). HER2/neu expression significantly correlated with advanced T stages (p = 0.02). In the total patient population, p21(Wafl/Cip1), p57(Kip2) and HER2/neu had no impact on survival of the patients. Among patients with a mutated p53 gene, those without p21(Wafl/Cip1) expression had a prolonged survival compared to patients with p21(Wafl/Cip1) expression (p = 0.004). Moreover, in p27(Kip1)-positive patients, those without p21(Wafl/Cip1) expression had a longer survival than those with p21(Wafl/Cip1) expression (p = 0.003). CONCLUSION In the subgroup of patients with a mutated p53 gene or in p27(Kip1)-positive patients, absence of p21(Wafl/Cip1) expression may be associated with longer survival of GC patients. Therefore, further analyses of this protein in larger patient populations are warranted.

Associations between Notch-2, Akt-1 and HER2/neu expression in invasive human breast cancer: a tissue microarray immunophenotypic analysis on 98 patients.

Abstract: Objective: We aimed to investigate the existence of associations between well-established and newly recognized biological and phenotypic features of breast cancer involved in tumor

Quantification and phenotypic characterization of circulating tumor cells for monitoring response to a preventive HER2/neu vaccine-based immunotherapy for breast cancer: a pilot study.

Abstract: Ongoing cancer vaccine trials are limited by the inability of immunologic assays to monitor clinically relevant surrogates of response. Recent advances in the ability to quantify and phenotype circulating tumor cells (CTCs) in breast cancer patients may lead to a role for CTCs in monitoring response to vaccine-based immunotherapy. The CellSearch System (Veridex-LLC, Warren, NJ) was used to enumerate total and HER2/neu + CTCs in 20 mL of blood from all 16 node-positive (NP) breast cancer patients active in our NP HER2/neu E75 peptide vaccine trial at the initiation of this pilot study. These patients were vaccinated with E75 (1000 μg)/GM-CSF (250 μg) monthly × 6 after completion of multimodality therapy. Mean (±SEM) number of CTCs and HER2/neu + CTCs were compared in unmatched (n = 16) and matched (n = 9) prevaccination and postvaccination cases. CTCs were detected in 14 of 16 (88%) patients (mean: 3.4 ± 0.2 CTC/20 mL). After vaccination, a reduction in CTC/20 mL (prevaccination 3.9 ± 1.5 vs postvaccination 0.7 ± 0.4, P = .077) and HER2/neu + CTC/20 mL (prevaccination 2.8 ± 1.0 vs postvaccination 0.5 ± 0.2, P = .048) was demonstrated. A significant delayed-type hypersensitivity (DTH) response suggesting that vaccination was effective in eliciting a peptide-specific immune response was confirmed (22.3 ± 4.1 vs 3.0 ± 2.2 [controls] mm, P < .01). All nine patients followed throughout the vaccination series also showed significant reduction in CTCs (4.8 ± 1.5 vs 0.3 ± 0.2, P < .01) and HER2/neu + CTCs (3.0 ± 0.9 vs 0.4 ± 0.2, P = .013). CTCs are readily demonstrated in posttreatment, clinically disease-free NP breast cancer patients. E75+GM-CSF vaccination appears to reduce the number of CTCs. These data suggest a potential role for this clinically validated CTC assay in assessing response to preventive vaccine-based immunotherapy, and further validation studies are underway.

Induction of adaptive Anti-HER2/neu immune responses in a Phase 1B/2 trial of 2B1 bispecific murine monoclonal antibody in metastatic breast cancer (E3194): a trial coordinated by the Eastern Cooperative Oncology Group.

Abstract: 2B1 is a bispecific murine monoclonal antibody that binds to the extracellular domains of HER2/neu and FcgammaRIII. 2B1 efficiently promotes the lysis of tumor cells overexpressing HER2/neu by natural killer cells and mononuclear phagocytes that express the FcgammaRIII A isoform. Here, we report the results of E3194, a phase 1B/2 trial conducted by the Eastern Cooperative Oncology Group that employed 2B1 therapy in 20 women with metastatic breast cancer. The median age was 51 years. All but 1 patient had received prior chemotherapy. After the first dose, 3 of the initial 8 patients experienced dose-limiting toxicities that required dose-reduction. The nature of these dose-limiting toxicities resulted in a reduced dose from 2.5 mg/m/d to 1 mg/m/d in the remaining 12 patients. Objective antitumor responses were not seen. However, 2B1 therapy induced adaptive immune responses to both intracellular and extracellular domains of HER2/neu. Even though 2B1 antibody therapy did not show activity in metastatic breast cancer at the current administered doses, the ability of this antibody to induce detectable immune responses against an important tumor antigen has implications for understanding the mechanisms by which antibodies that mediate antibody-directed cellular cytotoxicity may exert their clinical antitumor effects.

Antibody and CD8+ T Cell Responses against HER2/neu Required for Tumor Eradication after DNA Immunization with a Flt-3 Ligand Fusion Vaccine

Abstract: Purpose: HER2/neu is frequently overexpressed in breast cancer. In a mouse model, vaccination with HER2/neu DNA elicits antibodies that confer partial protection against tumor challenge. Experimental Design: To enhance antitumor immunity, we fused cDNA encoding Flt-3 ligand (FL) to the rat HER2/neu extracellular domain (neu), generating a chimeric FLneu molecule. FLneu and neu DNA vaccines were compared for immunogenicity and their ability to protect mice from tumor challenge. Results: The neu vaccine generated a HER2/neu-specific antibody response. In contrast, vaccination with FLneu induced CD8 + T cells specific for HER2/neu but a negligible anti-HER2/neu antibody response. The switch from an antibody-mediated to T cell–mediated response was due to different intracellular localization of neu and FLneu. Although the neu protein was secreted, the FLneu protein was retained inside the cell, co-localizing with the endoplasmic reticulum, facilitating processing and presentation to T cells. The neu and FLneu vaccines individually conferred only weak tumor immunity. However, efficient tumor rejection was seen when neu and FLneu were combined, inducing both strong anti-HER2/neu-specific antibody and T cell responses. Adoptive transfer of both immune CD8 + T cells and immune sera from immunized mice was required to confer tumor immunity in naive hosts. Conclusions: These results show that active induction of both humoral and cellular immunity to HER2/neu is required for efficient tumor protection, and that neither response alone is sufficient.

Evaluation of HER2/neu gene amplification in patients with invasive breast carcinoma. Comparison of in situ hybridization methods.

Abstract: One of the prognostic and predictive factors in invasive breast carcinomas is determination of the HER2/neu proto-oncogene amplification or HER2 protein overexpression. HER2 amplification/overexpression is associated with a more aggressive disease course, greater likelihood of recurrence and generally poor prognosis. The authors compared the specificity, simplicity of a given procedure and method standardization, the simplicity of evaluation the results of each in situ hybridization method and time needed for performing the test. Sixty-three cases of infiltrating breast carcinoma from surgically excised tumors and core needle biopsies were included in the study. The first step was the determination of HER2 status by immunohistochemistry. The patients with moderate (2+) and strong (3+) overexpression of HER2 protein were chosen for determining HER2 amplification by three methods of in situ hybridization: FISH, CISH and in situ hybridization with silver autometallography. The statistical analysis revealed a good agreement between IHC and ISH methods and among ISH methods. The results indicate that all in situ hybridization methods are equivalent tools for evaluating HER2 gene amplification in archival material. There is no clear answer which method is the best assay to determine HER2 marker status, although the authors present some advantages and disadvantages of all the described techniques and a proposed algorithm for choosing a method for a given laboratory.

Gefitinib prevents cancer progression in mice expressing the activated rat HER2/neu.

Abstract: We tested the efficacy of gefitinib in the prevention of HER2/neu-mediated breast cancer development in BALB-NeuT transgenic mice. Oral administration of gefitinib to female transgenic mice from 5 to 14 weeks of age reduced tumor multiplicity from 9.6 +/- 0.82 to 0.58 +/- 1.1 (83%). We observed a decrease in the number and size of lobules and lobular nodules in treated mice with a reduction in the overall disease burden per gland. Normal duct development in the mammary glands was not affected by gefitinib. The development of acinic cell carcinoma in the parotid glands of these animals was also reduced coincident with decreased stromal involvement during progression. Gefitinib eliminated phosphorylation of HER2 and HER3 and signaling through MAPK and Akt in lobular hyperplasias and carcinomas. At the same time MAPK activity and cytokine production in splenocytes and lymph nodes was increased in gefitinib-treated animals coincident with an increase in lymph node size. Delaying gefitinib treatment until mammary glands exhibited atypical lobular hyperplasias reduced efficacy. These studies demonstrate the critical role of HER2 signal transduction in the onset and progression of HER2/neu-dependent breast cancer and suggest a role for specific inhibitors to prevent the outgrowth of early hyperplastic disease.

Multiparameter noninvasive assessment of treatment susceptibility, drug target inhibition and tumor response guides cancer treatment.

Abstract: New cancer therapies are increasingly molecular-pathway specific. The evaluation of these novel therapies would be greatly facilitated by the development of noninvasive methods to assess multiple tumor cellular and molecular parameters. Using fluorescent probes specific for HER2/neu (AF750-trastuzumab) and apoptosis (Cy5.5-Annexin), we demonstrate a multichannel near infrared molecular imaging approach that yields accurate and early assessment of treatment susceptibility, drug target inhibition and tumor response during HER2-targeted therapy of orthotopic human mammary carcinomas in mice with trastuzumab (Herceptin). This combined approach detects both partial treatment response (tumor growth inhibition without regression) as well as therapeutic resistance before alterations in tumor growth are apparent. Partially responsive tumors exhibit increased Annexin signal when trastuzumab is combined with a cytotoxic agent (paclitaxel), which predicts subsequent tumor regression and suggests that imaging can guide therapy optimization. This multiparametric imaging approach has great potential in the clinical setting for determining patient eligibility, adequate drug dosing and early biological response of molecularly-targeted cancer therapies.

Coexpression of Flt3 ligand and GM-CSF genes modulates immune responses induced by HER2/neu DNA vaccine.

Abstract: DNA vaccine and dendritic cells (DCs)-based vaccine have emerged as promising strategies for cancer immunotherapy. Fms-like tyrosine kinase 3-ligand (Flt3L) and granulocyte-macrophage-colony-stimulating factor (GM-CSF) have been exploited for the expansion of DC. It was reported previously that combination of plasmid encoding GM-CSF with HER2/neu DNA vaccine induced predominantly CD4(+) T-cell-mediated antitumor immune response. In this study, we investigated the modulation of immune responses by murine Flt3L and GM-CSF, which acted as genetic adjuvants in the forms of bicistronic (pFLAG) and monocistronic (pFL and pGM) plasmids for HER2/neu DNA vaccine (pN-neu). Coexpression of Flt3L and GM-CSF significantly enhanced maturation and antigen-presentation abilities of splenic DC. Increased numbers of infiltrating DC at the immunization site, higher interferon-gamma production, and enhanced cytolytic activities by splenocytes were prominent in mice vaccinated with pN-neu in conjunction with pFLAG. Importantly, a potent CD8(+) T-cell-mediated antitumor immunity against bladder tumors naturally overexpressing HER2/neu was induced in the vaccinated mice. Collectively, our results indicate that murine Flt3L and GM-CSF genes coexpressed by a bicistronic plasmid modulate the class of immune responses and may be superior to those codelivered by two separate monocistronic plasmids as the genetic adjuvants for HER2/neu DNA vaccine.