Amplification of the neu (c-erbB-2) oncogene in human mammmary tumors is relatively frequent and is often accompanied by amplification of the linked c-erbA oncogene

Preliminary evaluation of HER-2/neu oncogene and epidermal growth factor receptor expression in normal and neoplastic human ovaries

The HER-2/neu oncogene (a member of the Erb-like oncogene family) is distinct from but closely related to the c-erb B gene which encodes the epidermal growth factor receptor (EGFr). HER-2/neu gene amplification was found in a large number of mammary carcinomas and there was a strong correlation between this phenomenon and poor prognosis. In our study HER-2/neu oncogene expression was determined in 16 malignant ovarian tumors, 2 ovarian lymphomas and 5 normal ovaries. The HER-2/neu gene was found both in normal ovaries and malignant tumors, without any apparent difference among the various histological types. In all the specimens examined, HER-2/neu expression did not seem to be related to EGF binding capacity.

Different Assays for Her-2/neu Evaluation in Breast Cancer

To evaluate different methodologic approaches for HER-2/neu analysis, we performed Southern, Northern, Western blot and histochemical assay on 112 samples from 86 primary tumors and 26 synchronous axillary metastatic lymph nodes of patients affected by operable breast cancer. Simultaneous statistical analysis of data obtained with the four methods (31 samples) showed that Western blot detected a higher percentage of alterations than the other assays (Cochran and Victor tests, 0.01 < p < 0.05). The same result was emphasized by pair analysis (McNemar, p < 0.05), which evaluated the assay data two by two. Immunohistochemical evaluations were more in accord with immunoprecipitation data when performed on frozen or Bouin-fixed, paraffin-embedded tissues than on formalin-fixed, paraffin-embedded tissues.

Immunohistochemical Expression of c-erbB-2 in Human Breast Cancer by Monoclonal Antibody: Correlation with Lymph Node and Er Status

c-erbB-2 Protein expression was investigated in a series of fifty primary breast cancers by means of a specific monoclonal antibody and immunocytochemistry. Specific staining was observed at the plasma membrane level of neoplastic cells, according to the reported localization of c-erbB-2 protein. Sixty-four percent of tumors scored positive, with a variable amount of stained cells. The rate of protein expression was found to exceed the reported gene amplification. No relationship was observed between c-erbB-2 protein staining and age, meno pausal status or histologic subtypes. An inverse association was found between c'erbB-2 protein staining and estrogen receptor content of tumors, assayed by immunocytochemistry. A positive relationship was observed between c-erbB-2 protein expression and presence of axillary node metastasis. These findings suggest that c-erbB-2 protein expression is a marker of tumor aggressiveness and that its prognostic power deserves further investigation both in node-positive and node-negative patients.

Genomic Alterations in Human Breast Cancer: A Review

We review and discuss data on the genetic alterations documented in human breast carcinomas at the molecular level. These alterations may result in: 1) deletion of genetic material (chromosome 11p, 13q, 3p, 1q, 17p); 2) amplification of genes or entire chromosomal segments (c-myc, c-erb-B2, locus DF3/PUM, loci on 11q13); 3) rearrangements (c-myc); 4) point mutations (c-ras). Presently available informations do not allow the development of cohesive pathogenetic models but indicate that the molecular basis of human breast cancer is heterogeneous.

Preliminary evaluation of HER-2/neu oncogene and epidermal growth factor receptor expression in normal and neoplastic human ovaries

The HER-2/neu oncogene (a member of the Erb-like oncogene family) is distinct from but closely related to the c-erb B gene which encodes the epidermal growth factor receptor (EGFr). HER-2/neu gene amplification was found in a large number of mammary carcinomas and there was a strong correlation between this phenomenon and poor prognosis. In our study HER-2/neu oncogene expression was determined in 16 malignant ovarian tumors, 2 ovarian lymphomas and 5 normal ovaries. The HER-2/neu gene was found both in normal ovaries and malignant tumors, without any apparent difference among the various histological types. In all the specimens examined, HER-2/neu expression did not seem to be related to EGF binding capacity.

Genetic variation of clock genes and cancer risk: a field synopsis and meta-analysis

BACKGROUND

The number of studies on the association between clock genes’ polymorphisms and cancer susceptibility has increased over the last years but the results are often conflicting and no comprehensive overview and quantitative summary of the evidence in this field is available.

RESULTS

Literature search identified 27 eligible studies comprising 96756 subjects (cases: 38231) and investigating 687 polymorphisms involving 14 clock genes. Overall, 1025 primary and subgroup meta-analyses on 366 gene variants were performed. Study distribution by tumor was as follows: breast cancer (n=15), prostate cancer (n=3), pancreatic cancer (n=2), non-Hodgkin's lymphoma (n=2), glioma (n=1), chronic lymphocytic leukemia (n=1), colorectal cancer (n=1), non-small cell lung cancer (n=1) and ovarian cancer (n=1).

We identified 10 single nucleotide polymorphisms (SNPs) significantly associated with cancer risk: NPAS2 rs10165970 (mixed and breast cancer shiftworkers), rs895520 (mixed), rs17024869 (breast) and rs7581886 (breast); CLOCK rs3749474 (breast) and rs11943456 (breast); RORA rs7164773 (breast and breast cancer postmenopausal), rs10519097 (breast); RORB rs7867494 (breast cancer postmenopausal), PER3 rs1012477 (breast cancer subgroups) and assessed the level of quality evidence to be intermediate. We also identified polymorphisms with lower quality statistically significant associations (n=30).

CONCLUSIONS

Our work supports the hypothesis that genetic variation of clock genes might affect cancer risk. These findings also highlight the need for more efforts in this research field in order to fully establish the contribution of clock gene variants to the risk of developing cancer.

METHODS

We conducted a systematic review and meta-analysis of the evidence on the association between clock genes’ germline variants and the risk of developing cancer. To assess result credibility, summary evidence was graded according to the Venice criteria and false positive report probability (FPRP) was calculated to further validate result noteworthiness. Subgroup meta-analysis was also performed based on participant features and tumor type. The breast cancer subgroup was further stratified by work conditions, estrogen receptor/progesterone receptor status and menopausal status, conditions associated with the risk of breast cancer in different studies.

Inhibition of 6-phosphofructo-2-kinase (PFKFB3) suppresses glucose metabolism and the growth of HER2+ breast cancer

PURPOSE

Human epidermal growth factor receptor-2 (HER2) has been implicated in the progression of multiple tumor types, including breast cancer, and many downstream effectors of HER2 signaling are primary regulators of cellular metabolism, including Ras and Akt. A key downstream metabolic target of Ras and Akt is the 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 isozyme (PFKFB3), whose product, fructose-2,6-bisphosphate (F26BP), is a potent allosteric activator of a rate-limiting enzyme in glycolysis, 6-phosphofructo-1-kinase (PFK-1). We postulate that PFKFB3 may be regulated by HER2 and contribute to HER2-driven tumorigenicity.

METHODS

Immunohistochemistry and Kaplan-Meier analysis of HER2+ patient samples investigated the relevance of PFKFB3 in HER2+ breast cancer. In vitro genetic and pharmacological inhibition of PFKFB3 was utilized to determine effects on HER2+ breast cancer cells, while HER2 antagonist treatment assessed the mechanistic regulation on PFKFB3 expression and glucose metabolism. Administration of a PFKFB3 inhibitor in a HER2-driven transgenic breast cancer model evaluated this potential therapeutic approach in vivo.

RESULTS

PFKFB3 is elevated in human HER2+ breast cancer and high PFKFB3 transcript correlated with poorer progression-free (PFS) and distant metastatic-free (DFMS) survival. Constitutive HER2 expression led to elevated PFKFB3 expression and increased glucose metabolism, while inhibition of PFKFB3 suppressed glucose uptake, F26BP, glycolysis, and selectively decreased the growth of HER2-expressing breast cancer cells. In addition, treatment with lapatinib, an FDA-approved HER2 inhibitor, decreased PFKFB3 expression and glucose metabolism in HER2+ cells. In vivo administration of a PFKFB3 antagonist significantly suppressed the growth of HER2-driven breast tumors and decreased ¹⁸F-2-deoxy-glucose uptake.

CONCLUSIONS

Taken together, these data support the potential clinical utility of PFKFB3 inhibitors as chemotherapeutic agents against HER2+ breast cancer.

Reduced risk of breast cancer associated with recreational physical activity varies by HER2 status

Convincing epidemiologic evidence indicates that physical activity is inversely associated with breast cancer risk. Whether this association varies by the tumor protein expression status of the estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), or p53 is unclear. We evaluated the effects of recreational physical activity on risk of invasive breast cancer classified by the four biomarkers, fitting multivariable unconditional logistic regression models to data from 1195 case and 2012 control participants in the population-based Women’s Contraceptive and Reproductive Experiences Study. Self-reported recreational physical activity at different life periods was measured as average annual metabolic equivalents of energy expenditure [MET]-hours per week. Our biomarker-specific analyses showed that lifetime recreational physical activity was negatively associated with the risks of ER-positive (ER+) and of HER2-negative (HER2−) subtypes (both P_trend ≤ 0.04), but not with other subtypes (all P_trend > 0.10). Analyses using combinations of biomarkers indicated that risk of invasive breast cancer varied only by HER2 status. Risk of HER2–breast cancer decreased with increasing number of MET-hours of recreational physical activity in each specific life period examined, although some trend tests were only marginally statistically significant (all P_trend ≤ 0.06). The test for homogeneity of trends (HER2– vs. HER2+ ) reached statistical significance only when evaluating physical activity during the first 10 years after menarche (P_homogeneity = 0.03). Our data suggest that physical activity reduces risk of invasive breast cancers that lack HER2 overexpression, increasing our understanding of the biological mechanisms by which physical activity acts.

T3 levels in relation to prognostic factors in breast cancer: a population-based prospective cohort study

BACKGROUND

The issue of a potential association between thyroid conditions/hormones and breast cancer has been studied extensively during the last decades but the results have been inconclusive and almost no studies have investigated breast cancer aggressiveness. We have previously found a positive association between prospectively measured levels of triiodothyronine (T3) and breast cancer incidence as well as breast cancer mortality. We now investigated prediagnostic T3 levels in relation to specific prognostic factors in breast cancer.

METHODS

The Malmö Preventive Project is a population-based prospective cohort including 2185 women in whom T3 levels were measured at baseline. That is, total T3 levels were measured before a potential diagnosis of breast cancer. Mean follow-up was 23.3 years and 149 women in the study population were diagnosed with invasive breast cancer. Tumours were classified according to selected prognostic factors of breast cancer; i.e. grade, tumour size, lymph node metastasis, and hormonal receptor status. T3 was handled both as tertiles and as a continuous variable. A Cox's proportional hazards analysis yielded hazard ratios with 95% confidence intervals. All analyses were also restricted to postmenopausal women.

RESULTS

Overall there was a statistically significant association between T3 and "all" breast cancers. The adjusted Hazard Ratio (HR) in the third tertile, as compared to the first, was (1.61:1.07-2.43). There was a statistically significant positive association between the third T3 tertile and large tumours, i.e. > 20 mm, (3.17:1.20-8.36) and the occurrence of lymph node metastases, (4.53:1.60-12.83). Other prognostic factors positively associated with T3 were negative oestrogen receptor (ER) status, (3.52:1.32-9.41) and negative progesterone receptor (PGR) status, (3.52:1.42-8.75). The analyses of T3 as a continuous variable and analysis restricted to postmenopausal women, confirmed the results but also showed an association with smaller tumours and in postmenopausal women a contemporary association with negative lymph nodes.

CONCLUSIONS

This prospective study of serum T3 levels in relation to breast cancer aggressiveness is the first of its kind. We found statistically significant positive associations between higher prediagnostic T3 levels and larger tumours, occurrence of lymph node metastases, and negative ER and PGR status.

HER2 and TOP2A amplification in a hospital-based cohort of breast cancer patients: associations with patient and tumor characteristics

Gene amplification is an important factor for altered gene expression in breast cancers. TOP2A-amplification often occurs concomitantly with HER2 amplification, and it has been suggested to be predictive for the response to anthracycline chemotherapy. This study assessed the correlation between HER2 status and TOP2A co-amplification, the possible association of TOP2A single-nucleotide polymorphisms with the frequency of this co-amplification as well as confirmation of association with outcome. HER2 and TOP2A amplification were analyzed in a tissue microarray from a clinical cohort study. Additionally, a common genetic variant (rs13695) in the TOP2A gene was genotyped in germline DNA. HER2 gene amplification was compared with HER2-IHC findings assessed during clinical routine work, and the association between all the biomarkers analyzed and the clinical outcome was determined. As an exploratory aim, rs13695 genotypes were compared with TOP2A amplification status. HER2 amplification was seen in 101 of 628 (16.1 %) and TOP2A amplification in 32 (5.1 %) cancers. No TOP2A amplification occurred without HER2 co-amplification. HER2 amplification was found in 8, 13.6, and 55.1 % of patients with HER2-IHC 0/1+, 2+, and 3+ tumors, respectively. HER2-IHC was not associated with an effect on the prognosis, but HER2-FISH was. There was an association between the rs13695 genotype and TOP2A amplification status (P = 0.03). Although there was a significant correlation between HER2 status determined by IHC and HER2 by FISH, only HER2 gene amplification status by FISH was correlated with outcome indicating greater utility for FISH in routine clinical settings.

Fluorescence in situ hybridization (FISH): an increasingly demanded tool for biomarker research and personalized medicine

Extensive studies of the genetic aberrations related to human diseases conducted over the last two decades have identified recurrent genomic abnormalities as potential driving factors underlying a variety of cancers. Over the time, a series of cutting-edge high-throughput genetic tests, such as microarrays and next-generation sequencing, have been developed and incorporated into routine clinical practice. Although it is a classical low-throughput cytogenetic test, fluorescence in situ hybridization (FISH) does not show signs of fading; on the contrary, it plays an increasingly important role in detecting specific biomarkers in solid and hematologic neoplasms and has therefore become an indispensable part of the rapidly developing field of personalized medicine. In this article, we have summarized the recent advances in FISH application for both de novo discovery and routine detection of chromosomal rearrangements, amplifications, and deletions that are associated with the pathogenesis of various hematopoietic and non-hematopoietic malignancies. In addition, we have reviewed the recent developments in FISH methodology as well.

Genetic features of thyroid hormone receptors

Thyroid hormone receptors (TR) are prototypes of nuclear transcription factors that regulate the expression of target genes. These receptors play an important role in many physiological processes. Moreover, a dysfunction of these proteins is often implicated in several human diseases and malignancies. Here we report genetic variations and alterations of the TRs that have been described in the literature as well as their potential role in the development of some human diseases including cancers. The functional effects of some mutations and polymorphisms in TRs on disease susceptibility, especially on cancer risk, are now established. Therefore, further investigations are needed in order to use these receptors as therapeutic targets or as biological markers to decide on appropriate forms of treatment.

The HER2 amplicon in breast cancer: Topoisomerase IIA and beyond

HER2 gene amplification is observed in about 15% of breast cancers. The subgroup of HER2-positive breast cancers appears to be heterogeneous and presents complex patterns of gene amplification at the locus on chromosome 17q12-21. The molecular variations within the chromosome 17q amplicon and their clinical implications remain largely unknown. Besides the well-known TOP2A gene encoding Topoisomerase IIA, other genes might also be amplified and could play functional roles in breast cancer development and progression. This review will focus on the current knowledge concerning the HER2 amplicon heterogeneity, its clinical and biological impact and the pitfalls associated with the evaluation of gene amplifications at this locus, with particular attention to TOP2A and the link between TOP2A and anthracycline benefit. In addition it will discuss the clinical and biological implications of the amplification of ten other genes at this locus (MED1, STARD3, GRB7, THRA, RARA, IGFPB4, CCR7, KRT20, KRT19 and GAST) in breast cancer.

Structure based antibody-like peptidomimetics

Biologics such as monoclonal antibodies (mAb) and soluble receptors represent new classes of therapeutic agents for treatment of several diseases. High affinity and high specificity biologics can be utilized for variety of clinical purposes. Monoclonal antibodies have been used as diagnostic agents when coupled with radionuclide, immune modulatory agents or in the treatment of cancers. Among other limitations of using large molecules for therapy the actual cost of biologics has become an issue. There is an effort among chemists and biologists to reduce the size of biologics which includes monoclonal antibodies and receptors without a reduction of biological efficacy. Single chain antibody, camel antibodies, Fv fragments are examples of this type of deconstructive process. Small high-affinity peptides have been identified using phage screening. Our laboratory used a structure-based approach to develop small-size peptidomimetics from the three-dimensional structure of proteins with immunoglobulin folds as exemplified by CD4 and antibodies. Peptides derived either from the receptor or their cognate ligand mimics the functions of the parental macromolecule. These constrained peptides not only provide a platform for developing small molecule drugs, but also provide insight into the atomic features of protein-protein interactions. A general overview of the reduction of monoclonal antibodies to small exocyclic peptide and its prospects as a useful diagnostic and as a drug in the treatment of cancer are discussed.

RECONSTRUCTING TUMOR PHYLOGENIES FROM HETEROGENEOUS SINGLE-CELL DATA

Studies of gene expression in cancerous tumors have revealed that tumors presenting indistinguishable symptoms in the clinic can be substantially different entities at the molecular level. The ability to distinguish between these genetically distinct cancers will make possible more accurate prognoses and more finely targeted therapeutics, provided we can characterize commonly occurring cancer sub-types and the specific molecular abnormalities that produce them. We develop a new method for identifying these common tumor progression pathways by applying phylogeny inference algorithms to single-cell assays, taking advantage of information on tumor heterogeneity lost to prior microarray-based approaches. We combine this approach with expectation maximization to infer unknown parameters used in the phylogeny construction. We further develop new algorithms to merge inferred trees across different assays. We validate the expectation maximization method on simulated data and demonstrate the combined approach on a set of fluorescent in situ hybridization (FISH) data measuring cell-by-cell gene and chromosome copy numbers in a large sample of breast cancers. The results further validate the proposed computational methods by showing consistency with several previous findings on these cancers and provide novel insights into the mechanisms of tumor progression in these patients.

Protein transduction domain delivery of therapeutic macromolecules

Owing to their unprecedented selectivity, specific activity and potential for 1000+ fold amplification of signal, macromolecules, such as peptides, catalytic protein domains, complete proteins, and oligonucleotides, offer great potential as therapeutic molecules. However, therapeutic use of macromolecules is limited by their poor penetration in tissues and their inability to cross the cellular membrane. The discovery of small cationic peptides that cross the membrane, called Protein Transduction Domains (PTDs) or Cell Penetrating Peptides (CPPs), in the late 1980s opened the door to cellular delivery of large, bioactive molecules. Now, PTDs are widely used as research tools, and impressively, multiple clinical trials are testing PTD-mediated delivery of macromolecular drug conjugates in patients with a variety of diseases.

Alteration of topoisomerase II-alpha gene in human breast cancer: association with responsiveness to anthracycline-based chemotherapy

PURPOSE

Approximately 35% of HER2-amplified breast cancers have coamplification of the topoisomerase II-alpha (TOP2A) gene encoding an enzyme that is a major target of anthracyclines. This study was designed to evaluate whether TOP2A gene alterations may predict incremental responsiveness to anthracyclines in some breast cancers.

METHODS

A total of 4,943 breast cancers were analyzed for alterations in TOP2A and HER2. Primary tumor tissues from patients with metastatic breast cancer treated in a trial of chemotherapy plus/minus trastuzumab were studied for amplification/deletion of TOP2A and HER2 as a test set followed by evaluation of malignancies from two separate, large trials for changes in these same genes as a validation set. Association between these alterations and clinical outcomes was determined.

RESULTS

Test set cases containing HER2 amplification treated with doxorubicin and cyclophosphamide (AC) plus trastuzumab, demonstrated longer progression-free survival compared to those treated with AC alone (P = .0002). However, patients treated with AC alone whose tumors contain HER2/TOP2A coamplification experienced a similar improvement in survival (P = .004). Conversely, for patients treated with paclitaxel, HER2/TOP2A coamplification was not associated with improved outcomes. These observations were confirmed in a larger validation set, where HER2/TOP2A coamplification was again associated with longer survival when only anthracycline-containing chemotherapy was used for treatment compared with outcome in HER2-positive cancers lacking TOP2A coamplification.

CONCLUSION

In a study involving nearly 5,000 breast malignancies, both test set and validation set demonstrate that TOP2A coamplification, not HER2 amplification, is the clinically useful predictive marker of an incremental response to anthracycline-based chemotherapy. Absence of HER2/TOP2A coamplification may indicate a more restricted efficacy advantage for breast cancers than previously thought.

Clinicopathological factors associated to HER-2 status in a hospital-based sample of breast cancer patients in Puerto Rico

Breast cancer is the most common female malignancy in Puerto Rico. Cases with human epidermal growth factor receptor 2 (HER-2) oncoprotein overamplification are associated with aggressive clinical behavior. Given the limited availability of information for Puerto Rico, we aimed to evaluate the prevalence and clinical correlates of HER-2 gene overexpression among a hospital-based female population of breast cancer cases. We analyzed data from 1,049 female patients with invasive breast cancer (diagnosed 2000-2005) at the I. González Martínez Oncologic Hospital and the Auxilio Mutuo Hospital. HER-2 status and other clinical characteristics were retrieved from the hospitals' cancer registries, from the Puerto Rico Central Cancer Registry, and from a review of medical and pathological records. Prevalence odds ratios were estimated with 95% confidence intervals, using logistic regression models to quantify the association between HER-2 status and different clinicophatological factors. The overall prevalence of positive HER-2 expression was 22.5%. In the multivariate logistic regression model, factors significantly associated with HER-2 positivity included a diagnosis age of < 50 years, having a tumor with negative progesterone receptor (PR) status, and having regional disease (p < 0.05). No significant differences in HER-2 positivity were observed by tumor histology or estrogen receptor (ER) status (p > 0.05). This is the most comprehensive epidemiological study to date on HER-2 status in Puerto Rico. The prevalence and correlates of HER-2 overexpression in this study are comparable to those observed in US populations. Study results will aid in the development of breast cancer control strategies in Puerto Rico.

Arecoline induced disruption of expression and localization of the tight junctional protein ZO-1 is dependent on the HER 2 expression in human endometrial Ishikawa cells

Background

Approximately 600 million people chew Betel nut, making this practice the fourth most popular oral habit in the world. Arecoline, the major alkaloid present in betel nut is one of the causative agents for precancerous lesions and several cancers of mouth among those who chew betel nut. Arecoline can be detected in the human embryonic tissue and is correlated to low birth weight of newborns whose mothers chew betel nut during pregnancy, suggesting that arecoline can induce many systemic effects. However, few reports exist as to the effects of arecoline in human tissues other than oral cancer cell lines. Furthermore, in any system, virtually nothing is known about the cellular effects of arecoline treatment on membrane associated signaling components of human cancer cells.

Results

Using the human Ishikawa endometrial cancer cell line, we investigated the effects of arecoline on expression, localization and functional connections between the ZO-1 tight junction protein and the HER2 EGF receptor family member. Treatment of Ishikawa cells with arecoline coordinately down-regulated expression of both ZO-1 and HER2 protein and transcripts in a dose dependent manner. Biochemical fractionation of cells as well as indirect immunofluorescence revealed that arecoline disrupted the localization of ZO-1 to the junctional complex at the cell periphery. Compared to control transfected cells, ectopic expression of exogenous HER2 prevented the arecoline mediated down-regulation of ZO-1 expression and restored the localization of ZO-1 to the cell periphery. Furthermore, treatment with dexamethasone, a synthetic glucocorticoid reported to up-regulate expression of HER2 in Ishikawa cells, precluded arecoline from down-regulating ZO-1 expression and disrupting ZO-1 localization.

Conclusion

Arecoline is known to induce precancerous lesions and cancer in the oral cavity of betel nut users. The arecoline down-regulation of ZO-1 expression and subcellular distribution suggests that arecoline potentially disrupts cell-cell interactions mediated by ZO-1, which may play a role in arecoline-mediated carcinogenesis. Furthermore, our study has uncovered the dependency of ZO-1 localization and expression on HER2 expression, which has therefore established a new cellular link between HER2 mediated signaling and apical junction formation involving ZO-1.

Poor prognostic significance of unamplified chromosome 17 polysomy in invasive breast carcinoma

The human epidermal growth factor receptor 2 (HER2) oncoprotein is overexpressed in about 20% of breast cancers, with HER2 gene amplification responsible for protein overexpression in the vast majority of patients. A subset of breast cancers have chromosome 17 aneusomy, due to either 17 monosomy (a single copy of chromosome 17) or polysomy (increased copy numbers of chromosome 17). Although HER2 overexpression is an established adverse prognostic factor in breast cancer, the role of unamplified chromosome 17 polysomy is uncertain and there is a paucity of literature on the correlation of chromosome 17 aneusomy with important prognostic and predictive pathologic factors in invasive breast carcinoma. Furthermore, while patients showing HER2 amplification with or without polysomy 17 are treated with trastuzumab with or without other chemotherapy, treatment of patients with unamplified chromosome 17 polysomy is not well defined. Currently most of these patients are treated similar to patients with neither amplification nor 17 polysomy. The aim of this study was to compare some prognostic and predictive factors in invasive breast carcinoma in patients with unamplified chromosome 17 polysomy with that seen in cases with HER2 gene amplification and those with neither amplification or polysomy. We found that invasive breast carcinomas with unamplified chromosome 17 polysomy are associated with several adverse prognostic indicators such as a higher nuclear grade, mitotic activity, Nottingham score, histologic grade, tumor stage, and greater estrogen receptor negativity with a trend towards the amplified group, in contrast to patients with neither amplification or polysomy. Although most patients with unamplified 17 polysomy have a 2+ equivocal score on immunohistochemistry, a minority has a 3+ positive score. An increased adverse role for unamplified polysomy along with 3+ protein expression in some patients supports the idea that these patients should be considered for therapy with trastuzumab and/or anthracyclines.

Network-based inference of cancer progression from microarray data

Cancer cells exhibit a common phenotype of uncontrolled cell growth, but this phenotype may arise from many different combinations of mutations. By inferring how cells evolve in individual tumors, a process called cancer progression, we may be able to identify important mutational events for different tumor types, potentially leading to new therapeutics and diagnostics. Prior work has shown that it is possible to infer frequent progression pathways by using gene expression profiles to estimate "distances" between tumors. Here, we apply gene network models to improve these estimates of evolutionary distance by controlling for correlations among coregulated genes. We test three variants of this approach: one using an optimized best-fit network, another using sampling to infer a high-confidence subnetwork, and one using a modular network inferred from clusters of similarly expressed genes. Application to lung cancer and breast cancer microarray data sets shows small improvements in phylogenies when correcting from the optimized network and more substantial improvements when correcting from the sampled or modular networks. Our results suggest that a network correction approach improves estimates of tumor similarity, but sophisticated network models are needed to control for the large hypothesis space and sparse data currently available.

Signal integration: a framework for understanding the efficacy of therapeutics targeting the human EGFR family

The human EGFR (HER) family is essential for communication between many epithelial cancer cell types and the tumor microenvironment. Therapeutics targeting the HER family have demonstrated clinical success in the treatment of diverse epithelial cancers. Here we propose that the success of HER family-targeted monoclonal antibodies in cancer results from their ability to interfere with HER family consolidation of signals initiated by a multitude of other receptor systems. Ligand/receptor systems that initiate these signals include cytokine receptors, chemokine receptors, TLRs, GPCRs, and integrins. We further extrapolate that improvements in cancer therapeutics targeting the HER family are likely to incorporate mechanisms that block or reverse stromal support of malignant progression by isolating the HER family from autocrine and stromal influences.

Differential binding patterns of monoclonal antibody 2C4 to the ErbB3-p185her2/neu and the EGFR-p185her2/neu complexes

2C4 (Pertuzumab, Omnitarg) is a monoclonal antibody targeting p185(her2/neu), which is overexpressed in 30% of invasive breast cancer. 2C4 is currently in phase II clinical trials for several types of cancers. This antibody has been reported to disrupt the association between p185(her2/neu) and ErbB3. In our studies of epidermal growth factor receptor (EGFR)-p185(her2/neu) heterodimerization, we noted that 2C4 formed associations with the EGFR-p185(her2/neu) receptor complex. Our data argue against 2C4 as a universal heterodimerization blocker for p185(her2/neu), but indicate that cocktails of monoclonal antibodies binding distinct interaction surfaces of p185(her2/neu) will emerge as the most potent targeted therapy.

ErbB receptors: from oncogenes to targeted cancer therapies

Understanding the genetic origin of cancer at the molecular level has facilitated the development of novel targeted therapies. Aberrant activation of the ErbB family of receptors is implicated in many human cancers and is already the target of several anticancer therapeutics. The use of mAbs specific for the extracellular domain of ErbB receptors was the first implementation of rational targeted therapy. The cytoplasmic tyrosine kinase domain is also a preferred target for small compounds that inhibit the kinase activity of these receptors. However, current therapy has not yet been optimized, allowing for opportunities for optimization of the next generation of targeted therapy, particularly with regards to inhibiting heteromeric ErbB family receptor complexes.

High-resolution ROMA CGH and FISH analysis of aneuploid and diploid breast tumors

Combining representational oligonucleotide microarray analysis (ROMA) of tumor DNA with fluorescence in situ hybridization (FISH) of individual tumor cells provides the opportunity to detect and validate a wide range of amplifications, deletions, and rearrangements directly in frozen tumor samples. We have used these combined techniques to examine 101 aneuploid and diploid breast tumors for which long-term follow-up and detailed clinical information were available. We have determined that ROMA provides accurate and sensitive detection of duplications, amplifications, and deletions and yields defined boundaries for these events with a resolution of <50 kbp in most cases. We find that diploid tumors exhibit fewer rearrangements on average than aneuploids, but rearrangements occur at the same locations in both types. Diploid tumors reflect at least three consistent patterns of rearrangement. The reproducibility and frequency of these events, especially in very early stage tumors, provide insight into the earliest chromosomal events in breast cancer. We have also identified correlations between certain sets of rearrangement events and clinically relevant parameters such as long-term survival. These correlations may enable novel prognostic indicators for breast and other cancers as more samples are analyzed.

Biological variables and prognosis of DCIS

Based on current knowledge, biological factors that have been investigated in ductal carcinoma in situ (DCIS) include histology of these lesions, the impact of margin status on local recurrence, and several genetic alterations. Optimal integration of these factors in guiding optimal therapy is of great importance, since the incidence of DCIS is rising as a result of population-based mammographic screening. Mastectomy will almost always cure patients with DCIS but represents overtreatment for many. Less extensive treatment options should combine an optimal cosmetic result with the same safety for outcome of disease as mastectomy. To guide such optimal treatment, histological classification is not sufficient and additional biological factors are being investigated for their ability to predict outcome for individual patients with DCIS. In this review, the histological classification of DCIS is described and in addition the emerging knowledge on genetic alterations is summarised. For clinical management of DCIS patients, genetic or other biological factors should be identified that can predict the risk of progression of DCIS to invasive breast cancer and distant metastases. At present, insufficient knowledge on prognostic and predictive factors in DCIS is available. Research in this area is hampered by the difficulties in obtaining DCIS tumour tissue, as the tumour cells grow in the lumen of pre-existing ducts and lobules. As the recurrence rates are relatively low and the most relevant clinical endpoint, distant metastases, is indeed very rare, large numbers of patients (hundreds to a few thousand) need to be studied. Integration of translational studies into clinical trials aimed at optimising the treatment of DCIS are required to achieve this goal.

Hormone Receptor Status Does Not Affect the Clinical Benefit of Trastuzumab Therapy for Patients with Metastatic Breast Cancer

BACKGROUND

Hormone receptor (HR) and HER2 signaling pathways are involved in the regulation of breast cancer proliferation. The impact of HR status on the clinical outcome of patients with HER2-overexpressing disease treated with the monoclonal antibody trastuzumab is unknown.

PATIENTS AND METHODS

To evaluate this, we conducted a retrospective analysis of 805 patients with metastatic breast cancer enrolled in 3 clinical trials comparing trastuzumab in combination with chemotherapy versus chemotherapy alone or trastuzumab monotherapy as first-, second-, or third-line treatment. Patients whose tumor samples overexpressed HER2 by fluorescence in situ hybridization (FISH) were stratified based on HR status, and clinical outcomes were compared.

RESULTS

Tumor samples from 596 of 805 patients were HER2overexpressing by FISH; 45% of these were HR-positive and 43% were HR-negative (HR status was unknown in 12%). Overall response rate (ORR) and time to progression (TTP) were significantly higher in patients treated with chemotherapy plus trastuzumab than in those treated with chemotherapy alone, irrespective of HR status. Median survival was longer for patients with HR-positive tumors receiving combination therapy compared with those with HR-negative tumors. In the trastuzumab monotherapy trials, ORR and TTP were similar for patients with HR-positive and HR-negative tumors. Median survival was longer for patients with HR-positive tumors compared with those with HR-negative tumors.

CONCLUSION

Hormone receptor status did not affect the clinical benefit of trastuzumab given as a single agent or combined with chemotherapy. The addition of trastuzumab to chemotherapy provides an improved clinical benefit compared with chemotherapy alone, regardless of HR status.

Receptor-Targeted Cancer Therapy

Insight into the molecular mechanisms of malignant transformation is changing the way cancer is being treated. Conventional treatment strategies target the DNA of all dividing cells, resulting in a significantly increased risk of collateral toxicity. In addition, the accumulation of multiple mutations leads to drug resistance in many cancer cells. Targeted strategies have now been developed that specifically disrupt oncogenically active cell surface receptors and endogenous signaling molecules. These agents have a much greater selectivity for tumor tissue and decreased risk of side effects. Increased signaling through ErbB receptors via gene amplification, overexpression, and mutation has been implicated in many human cancers and associated with poor prognosis. Interruption of this process has been shown to cause antitumor effects. Downregulation of the ErbB receptors, HER-2/neu, and later EGFR, with monoclonal antibodies was the first demonstration of targeted therapy. Subsequently, the ErbB tyrosine kinase domain has been successfully targeted with small molecule inhibitors. The development of novel ErbB-directed entities is ongoing, with particular promise being shown by strategies targeting receptor interaction in oligomeric complexes.

Thyroid hormone and breast carcinoma. Primary hypothyroidism is associated with a reduced incidence of primary breast carcinoma

BACKGROUND

To investigate the role of primary hypothyroidism (HYPT) on breast carcinogenesis, the authors evaluated 1) the association between HYPT and a diagnosis of invasive breast carcinoma and 2) the clinicopathologic characteristics of breast carcinoma in patients with HYPT.

METHODS

For this retrospective chart review study, 1136 women with primary breast carcinoma (PBC) were identified from the authors' departmental data base. These women (cases) were frequency-matched for age (+/- 5 years) and ethnicity with 1088 healthy participants (controls) who attended a breast carcinona screening clinic. Women with HYPT who were receiving thyroid-replacement therapy before they were diagnosed with breast carcinoma or before the screening visit were identified.

RESULTS

The mean ages of cases and controls (51.6 years vs. 51.0 years, respectively; P = 0.30) and their menopausal status (65.4% premenopausal vs. 62% postmenopausal; P = 0.10) were comparable. Two hundred forty-two women in the case group (10.9%) with HYPT were identified. The prevalence of this condition was significantly greater the control group compared with the case group (14.9% vs. 7.0%, respectively; P < 0.001). PBC patients were 57% less likely to have HYPT compared with their healthy counterparts (odds ratio, 0.43l 95% confidence interval, 0.33-0.57). Seventy-eight white patients with PBC had HYPT and, compared with women who were euthyroid, they were older at the time of diagnosis (58.8 years vs. 51.1 years; P < 0.001), were more likely to have localized disease (95.0% vs. 85.9% clinical T1 or T2 disease, respectively; P = 0.025), and were more likely to have no pathologic lymph node involvement (62.8% vs. 54.4%; P = 0.15).

CONCLUSIONS

Primary HYPT was associated with a reduced risk for PBC and a more indolent invasive disease. These data suggest a possible biologic role for thyroid hormone in the etiology of breast carcinoma and indicate areas of research for the prevention and treatment of breast carcinoma.

Overexpression of the HER-2 oncogene does not play a role in high-grade osteosarcomas

The aim of our study was to determine whether or not the tyrosine kinase receptor, HER2 (also known as ErbB2/Her2/neu), is overexpressed in human osteosarcomas (OS). We studied 15 biopsy and 18 resection specimens at the mRNA and protein levels. HER2 status in the OS specimens was assessed by immunohistochemistry (IHC) and quantitative Real-Time Polymerase chain reaction (PCR). In moderately immunopositive cases fluorescent in situ hybridisation (FISH) analysis was used in order to identify any possible gene amplification. 27 samples were evaluable for IHC and only 1 case showed a moderately positive membrane staining. The remaining samples showed no staining or focal cytoplasmic staining (2 samples). In the moderately positive case, FISH analysis showed no HER-2 gene amplification. There was also no overexpression of HER2 mRNA suggesting this sample was a false-positive immunostain. HER2 mRNA expression was present in all samples at a similar level to that in the breast cancer cell line, MCF7, which does not overexpress HER2 and was used as a negative control. In conclusion, this study shows that HER2 mRNA or membranous HER2 protein overexpression is absent in human OS. We noted various inconsistencies in previous published studies, with regard to methodology and the interpretation of the results based on poor methodology. We therefore conclude that the positive data with regard to HER2 overexpression reported in these previous studies is not reliable. Our results suggest that the monoclonal antibody trastuzumab (Herceptin(R)), directed against the HER2-receptor, is not likely to be an effective therapeutic agent in OS.

Amplification of a 280-kilobase core region at the ERBB2 locus leads to activation of two hypothetical proteins in breast cancer

Amplification of the ERBB2 oncogene at 17q12 is clinically the most relevant genetic aberration in breast cancer and several studies have linked ERBB2 activation to poor clinical outcome. The development of targeted antibody-based therapy for ERBB2-overexpressing tumors and the possible role of ERBB2 as a predictor of chemotherapy treatment response have further emphasized the essential role of ERBB2 in breast cancer. Here, we performed a detailed characterization of the molecular events occurring at the ERBB2 amplicon in primary breast tumors. Analysis of the amplicon structure in 330 breast tumors by fluorescence in situ hybridization to a tissue microarray revealed a 280-kb common region of amplification that contains 10 transcribed sequences, including eight known genes. The expression levels of these 10 transcripts were determined in 36 frozen samples of grade-matched ERBB2-amplified and -nonamplified (as determined by fluorescence in situ hybridization) primary breast tumors by using quantitativereal-time reverse transcriptase-polymerase chain reaction. A highly significant association between amplification and expression levels was observed for six of these genes, including ERBB2 and two uncharacterized hypothetical proteins, MGC9753 and MGC14832. These results support the recent findings on the influence of copy number on gene expression levels and highlight novel genes that might contribute to the clinical behavior of ERBB2-amplified breast tumors.

Adoptive immunotherapy: engineering T cell responses as biologic weapons for tumor mass destruction

Adoptive T cell immunotherapy is an evolving technology with the potential of providing a means to safely and effectively target tumor cells for destruction.

HER-2/neu and topoisomerase IIalpha in breast cancer

In breast cancer, the predominant genetic mechanism for oncogene activation is through an amplification of a gene. The HER-2 (also known as ErbB2/c-erbB2/HER-2/neu) oncogene is the most frequently amplified oncogene in breast cancer, and its overexpression is associated with poor clinical outcome. In addition to its important role in breast cancer growth and progression, HER-2 is also a target for a new form of chemotherapy. Breast cancer patients have been treated with considerable success since 1998 with trastuzumab, a recombinant antibody designed to block signaling through HER-2 receptor. HER-2 has also been implicated in altering the chemosensitivity of breast cancer cells to different forms of conventional cytotoxic chemotherapy, particularly of topoII-inhibitors (e.g., anthracyclines). Topoisomerase IIalpha gene is located just by the HER-2 oncogene at the chromosome 17q12-q21 and is amplified or deleted in almost 90% of the HER-2 amplified primary breast tumors. Recent data suggests that amplification and deletion of topoisomerase IIalpha may account for both relative chemosensitivity and resistance to anthracycline therapy, depending on the specific genetic defect at the topoIIalpha locus. Expanding our understanding of HER-2 amplification also changes its role in the pathogenesis of breast cancer. HER-2 is an oncogene that clearly can drive tumor induction and growth and is also a target for a new kind of chemotherapy, but its function as a marker for chemoselection may be due to associated genetic changes, of which topoisomerase IIalpha is a good example. Moreover, despite potential evidence that genes other than HER-2, such as topoisomerase IIalpha, may be more important predictors of therapeutic response in breast cancer, HER-2 status still has a very significant role in therapeutic selection, mainly as the major criterion for administering trastuzumab in treating breast cancer. Thus, the clinical and therapeutic importance of the HER-2 and topoisomerase IIalpha status to breast cancer management should only increase in the next few years.

C-erbB2 oncoprotein and its soluble ectodomain: a new potential tumor marker for prognosis early detection and monitoring patients undergoing Herceptin treatment

c-erbB-2 oncoprotein (or p185) coded by c-erbB-2 oncogene can be extracted with detergent from cell membrane of breast tissue and breast tumor cell line. The ectodomain of p185 can be cleaved proteolytically from the transmembrane receptor and released into solution. In blood circulation, only the ectodomain can be found, whereas only p185 exists in the extracts of tissue and cell line. p185 can also be quantified in the fine-needle aspirate biopsies and the concentration of p185 from the biopsies of malignant breast tissue is much higher than that of the normal and benign tissue. Measuring the ectodomain of the c-erbB-2 oncoprotein not only is useful to identify breast cancer patient who will benefit from Herceptin treatment but also can be used to monitor patients during the treatment. Overexpression of p185 and the elevation of circulating ectodomain is usually associated with poor prognosis. Overexpression of p185 in breast cancer patients with positive estrogen receptor identifies a subgroup of patients who will not respond to the endocrine therapy. Activation of p185 appears to be an early event in tumorigenesis for some cancers. It is possible that the ectodomain could be used as an early tumor marker detecting benign disease.

Expression of thyroid hormone receptor/erbA genes is altered in human breast cancer

The relation between thyroid status and diseases and cancer is unclear. No detailed analysis of thyroid hormone receptor (TR) expression in human breast cancer has been reported. We have analysed the expression and mutational status of the TRalpha1, encoded by the c-erbA proto-oncogene, TRbeta1 and TRbeta2 isoforms in 70 sporadic breast cancers. Alterations in the RNA level of TRbeta1, TRalpha1, or both were found in a number of patients. No expression of TRbeta2 RNA was detected. Western blotting analysis confirmed the differences in expression at the protein level in those cases where sufficient tumor sample was available. Additionally, tumor-specific truncated TRbeta1 RNA was found in six patients. Strikingly, three transcripts shared the same breakpoint. Only one tumor carried the corresponding deletion at the genomic DNA level, suggesting that the remaining abnormal TRbeta1 transcripts are aberrant splicing products. Though no significant correlation was found between TRbeta1 alteration and any clinical parameter, it showed a tendency to associate with early age of onset (<50 years). Our results reveal specific alterations in the expression of TRbeta and TRalpha genes in a subset of breast cancer patients, suggesting that deregulation of thyroid hormone target genes may be involved in the generation of this neoplasia.

Inhibition of proliferation and expression of T1 and cyclin D1 genes by thyroid hormone in mammary epithelial cells

The relationship between thyroid hormone (triiodothyronine, T(3)) and breast cancer is unclear. We studied the effect of the c-erbA/TR alpha proto-oncogene encoding a functional T(3) receptor (TR alpha 1), of its ligand T(3), and of its retroviral, mutated counterpart, the v-erbA oncogene, on the proliferation capacity of nontumorigenic mammary epithelial cells (EpH4). We found that EpH4 cells expressing ectopically TR (EpH4 + TR alpha 1) or v-erbA (EpH4 + v-erbA) proliferated faster than parental EpH4 cells that contained low levels of endogenous TR. T(3) inhibited DNA synthesis and proliferation in EpH4 + TR alpha 1 cells but not EpH4 or EpH4 + v-erbA cells. The study of cell-cycle genes showed that T(3) decreased cyclin D1 RNA and protein levels in EpH4 + TR alpha 1 cells. In addition, T(3) downregulated the expression of T1, a gene that is overexpressed in human breast adenocarcinomas and is induced by mitogens, serum, and several oncogenes and cytokines. Inhibition of the T1 gene by T(3) required both de novo mRNA and protein synthesis. Furthermore, T(3) abolished the induction of T1 by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate and inhibited the activity of an activation protein 1-dependent promoter (-73-Col-CAT) in EpH4 + TR alpha 1 cells, suggesting that interference with activation protein 1 transcription factor plays a part in the inhibition of the T1 gene. Our results showed that T(3) reduced the proliferation of mammary epithelial cells and inhibited the expression of cyclin D1 and T1 genes.

HER2/neu expression in malignant lung tumors

Despite intensive treatment efforts, the prognosis for lung cancer is very poor; less than 15% of patients survive 5 years. Trastuzumab, a monoclonal antibody targeting the HER2/neu protein receptor, is effective in the treatment of metastatic breast cancer and may be useful in the treatment of non-small cell lung cancer (NSCLC). Using the HercepTest (Dako; Carpenteria, CA), 25% of NSCLC show 2+ or greater HER2/neu expression, but only 6% to 8% of NSCLC tumors have 3+ overexpression. Positive HER2/neu expression is most often seen in adenocarcinomas compared with squamous cell carcinomas or large cell carcinomas, and is rarely seen in small cell lung cancer. As determined by fluorescence in situ hybridization analysis, the high degree of HER2/neu gene expression and gene amplification seen in breast cancer is lower in NSCLC. Polysomy is the cause of increased HER2/neu expression in most NSCLC. Prospective clinical studies with trastuzumab in lung cancer are ongoing. Future studies in NSCLC need to include immunohistochemistry and fluorescence in situ hybridization analysis to determine the method of choice for evaluating clinically relevant HER2/neu-positive tumors.

Amplification of oncogenes revisited: from expression profiling to clinical application

Regulatory or structural alterations of cellular oncogenes have been implicated in the causation of cancers. Amplification represents one of the major molecular pathways by which gene expression is constitutively enhanced above the level of physiologically normal variation. Consequently, the significance of oncogene amplification in tumorigenesis originally had emerged from expression profiling of tumor cells by oncogene arrays. Amplified oncogenes have been found associated with more aggressive tumor variants and in selected settings are clinical markers to determine patient prognosis.

Multiple regulatory elements in the murine stromelysin-3 promoter. Evidence for direct control by CCAAT/enhancer-binding protein beta and thyroid and retinoid receptors

Stromelysin-3 (ST3) belongs to the matrix metalloproteinase (MMPs) family, a protease family involved in tissue remodeling. Although this family of enzymes is regulated by nuclear receptors, few hormone-responsive elements have been demonstrated in MMP promoters. In order to identify regulatory elements and/or factors that control the expression of the mouse st3 gene, we have analyzed genomic sequences encompassing 5 kilobase pairs of the ST3 promoter. Analysis of these sequences revealed several CCAAT/enhancer-binding proteins (C/EBP) and retinoic acid-responsive elements (RAREs), as well as one thyroid-responsive element. However, in contrast to most MMP promoters, no AP-1-binding sites were identified. Specific binding activities were demonstrated for all elements. Consistent with previous reports, retinoid X receptor is required for maximal binding to the ST3 RAREs and the TRE. The ST3-C/EBP element was shown to mediate dose-dependent promoter activation by C/EBPbeta. Among the RAREs, the proximal DR1-RARE was shown to be sufficient for ST3 promoter activation by ligand-bound retinoid receptors, whereas the two distal DR2-RAREs appear to be involved more in the control of base-line promoter activity. Accordingly, ST3 expression was induced by retinoic acid and was reduced in cells where specific retinoic acid receptors had been inactivated. The involvement of these conserved regulatory elements is discussed in the context of physiological or pathological situations associated with st3 expression. Our findings therefore assign to C/EBP, retinoids, and thyroid hormone important roles in the regulation of ST3 gene expression.

Effects of HER-2/neu on chemosensitivity of tumor cells

In solid tumors, such as breast and ovarian cancer, the predominant genetic mechanism for oncogene activation is through gene amplification. The HER-2 (also known as ErbB2/c-erbB2/HER-2 / neu) oncogene is the most frequently amplified oncogene in breast cancer and its overexpression is associated with poor clinical outcome. In addition to its role in tumor progression, HER-2 has been implicated in altering tumor cell chemosensitivity to cytotoxic chemotherapy, particularly to anthracyclines. However, sophisticated in vitro studies have recently indicated that HER-2 may not have anything to do with the sensitivity of the cancer cells to cytotoxic drugs. Topoisomerase IIalpha gene is a target gene for many cytotoxic drugs and is located just by the HER-2 at the 17q12-q21. TopoIIalpha amplification and deletion may account for both relative chemosensitivity and resistance to anthracycline-therapy depending on the specific genetic defect at the topoIIalpha locus. Whereas HER-2 is an oncogene that clearly can drive tumor induction and growth, its function as a marker for chemoselection may be due to associated genetic changes in the topoIIalpha gene. Copyright 2000 Harcourt Publishers Ltd.

Immunoelectron microscopical identification of the c-erbB-2 oncoprotein in patients with laryngeal squamous cell carcinoma

The peroxidase-antiperoxidase (PAP) method was used for localization of the c-erbB-2 oncoprotein at the electron microscopical level in 15 patients with laryngeal squamous cell carcinoma. It was found that c-erbB-2 oncoprotein was present in 7 of 15 samples. Electron microscopical examination revealed expression of the c-erbB-2 oncoprotein both on the membrane of individual cells and in the cytoplasm. In 5 of the 7 cases of positive labeling, it was observed only on the plasma membrane of cells whereas in 2 cases, there was also cytoplasmic staining. Reaction product was associated with endoplasmic reticulum, and the nuclear envelope and was scattered throughout the cytoplasm on ribosomes. Control incubations using normal rabbit serum instead of the primary antibody showed no labeling. A significant correlation between c-erbB-2 oncoprotein and pathological characteristics such as nodal status and histological grade was not found.

The significance of histological determination of HER-2 status in breast cancer

Since the identification of the novel transforming gene neu in rat neuroblastomas in 1981, and the subsequent cloning of the human equivalent HER-2, there have been considerable developments concerning the role and value of HER-2 in human breast cancer. Early studies found gene amplification in 20-30% of breast carcinomas, with most studies linking this to poorer survival. Numerous antibodies have been generated against the oncoprotein and in many instances overexpression, as defined by membrane staining of breast cancer cells, correlated with gene amplification. Many studies, but not all, have found an association between HER-2 reactivity and poor prognosis. HER-2 can also be detected in high-grade ductal carcinoma in situ. HER-2 status can also aid prediction of response to hormonal and chemotherapy, but the present interest lies in the humanized monoclonal antibody against HER-2 (Herceptin) that has been developed. This is only of value if there is over-expression of HER-2 by a breast cancer, and so a reliable, accurate method of determination of HER-2 status is required. Immunohistochemistry is widely used and is relatively simple, with no major equipment requirements. However, there are variations in results with different antibodies and standardized methods, with controls for evaluating extent of reactivity required. Fluorescent in situ hybridization, which detects gene amplification, is an alternative approach that can be used with fixed embedded tissue but the technique is less widely available. HER-2 is the first oncoprotein involved in breast cancer in which there has been direct translation from the laboratory to the patient.

DNA vaccination with full-length or truncated neu induces protective immunity against the development of spontaneous mammary tumors in HER-2/neu transgenic mice

Genetic immunization against tumor antigens is an effective way to induce an immune response able to oppose cancer progression. Overexpression of HER-2/neu can lead to neoplastic transformation and has been found in many human primary breast cancers. We constructed DNA expression vectors encoding the full-length neu oncogene of rat cDNA (pCMV-NeuNT), the neu extracellular domain (pCMV-ECD), or the neu extracellular and transmembrane domains (pCMV-ECD-TM). We evaluated whether i.m. injection of these plasmids induces protection against the development of mammary tumors occurring spontaneously in FVB/N neu-transgenic mice. We found that pCMV-ECD-TM induced the best protection, whereas both pCMV-ECD and pCMV-NeuNT were less effective. The coinjection with a bicistronic vector for murine IL-12 increased the efficacy of pCMV-ECD and pCMV-NeuNT plasmids, and led to the same protection obtained with pCMV-ECD-TM alone. Anti-neuECD antibodies were detected in pCMV-ECD-TM vaccinated mice and, after coinjection with pCMV-IL12 plasmids, they appeared also in animals immunized with pCMV-ECD. Our data demonstrate the effectiveness of DNA vaccination using truncated Neu plasmids in inducing antitumor protection in a spontaneous mammary tumor model.

Amplification and deletion of topoisomerase IIalpha associate with ErbB-2 amplification and affect sensitivity to topoisomerase II inhibitor doxorubicin in breast cancer

Topoisomerase IIalpha (topoIIalpha) is a key enzyme in DNA replication and a molecular target for many anti-cancer drugs called topoII inhibitors. The topoIIalpha gene is located at chromosome band 17q12-q21, close to the ErbB-2 oncogene (HER-2/neu), which is the most commonly amplified oncogene in breast cancer. Because of the physical proximity to ErbB-2, copy number aberrations may also occur in the topoIIalpha gene. These topoIIalpha gene copy number aberrations may be related to the altered chemosensitivity to topoII inhibitors that breast cancers with ErbB-2 amplification are known to have. We used fluorescence in situ hybridization to study copy number aberrations of both topoIIalpha and ErbB-2 in nine breast cancer cell lines and in 97 clinical breast tumors, which were selected for the study according to their ErbB-2 status by Southern blotting. TopoIIalpha-protein expression was studied with Western blot and sensitivity to doxorubicin (a topoII inhibitor) with a 96-well clonogenic in vitro assay. Two of the five cell lines with ErbB-2 gene amplification (SK-BR-3 and UACC-812) showed amplification of topoIIalpha. In MDA-361 cells, ErbB-2 amplification (14 copies/cell) was associated with a physical deletion of topoIIalpha (four copies of chromosome 17 centromere and two copies of topoIIalpha). The topoIIalpha amplification in UACC-812 cells was associated with 5.9-fold-increased topoIIalpha protein expression and 2.5-fold-increased sensitivity to the topoII inhibitor, doxorubicin, whereas the deletion in MDA-361 leads to decreased protein expression (45% of control) and a 2.4-fold-increased chemoresistance in vitro. Of 57 ErbB-2-amplified primary breast carcinomas, 25 (44%) showed ErbB-2-topoIIalpha coamplification and 24 (42%) showed a physical deletion of the topoIIalpha gene. No topoIIalpha copy number aberrations were found in 40 primary tumors without ErbB-2 amplification. TopoIIalpha gene amplification and deletion are common in ErbB-2-amplified breast cancer and are associated with increased or decreased sensitivity to topoII inhibitors in vitro, respectively. These findings may explain the altered chemosensitivity to topoII inhibitors reported in ErbB-2-amplified breast cancers.