c-erbB-2 expression in primary breast cancer.

c-erbB-2 is an oncoprotein which is overexpressed in up to 40% of primary breast cancers. c-erbB-2 overexpression is a bad prognostic factor in patients with lymph node-positive disease. Unfortunately, there has been no agreement to date on whether c-erbB-2 overexpression is of prognostic significance in patients with lymph node-negative disease. c-erbB-2 overexpression is correlated with the absence of estrogen receptor expression in a number of publications. Correlation between c-erbB-2 overexpression and hormone sensitivity in the clinical setting is less well established and is the focus of ongoing studies. Both preclinical and clinical studies support an association between c-erbB-2 receptor overexpression and resistance to alkylating agents. In contrast, the data for c-erbB-2 and anthracyclines should be viewed in a slightly different manner. Anthracyclines appear to have a greater therapeutic effect in c-erbB-2-positive disease which may be dose sensitive. In c-erbB-2-negative disease not only is the therapeutic effect reduced but there does not appear to be any improved response to higher doses of anthracyclines. The data for c-erbB-2 and the taxanes is still not clear enough to provide any definite conclusions. If there is a correlation it would at present appear to be between paclitaxel and response rates, but this needs to be confirmed in larger studies. Few studies have looked at changes in c-erbB-2 on therapy. Those that have seem to show no significant change on either tamoxifen or chemotherapy.     

The c-erbB-2 proto-oncogene as a prognostic and predictive marker in breast cancer: A paradigm for the development of other macromolecular markers-A review

Seven years after the initial studies of the prognostic value of the proto-oncogene c-erbB-2 in breast cancer, its role is still being defined. The interpretation of studies on the use of this gene and its protein product in prognostic and predictive tests for breast cancer is complicated by multiple methodologies and the inherent difficulties in the studies. The work has moved beyond the stage at which small studies with short follow-up (useful for hypothesis generation) are of value, to the stage in which large studies with sufficient statistical power to find significant correlations are central. These larger studies do not lend support for the use of c-erbB-2 in the evaluation of axillary-node-negative patients, the group of breast cancer patients for whom refinement of prognostic estimates is now most important. There are, however, hints that c-erbB-2 may have value in predicting response to certain treatments, though the studies so far are too few, often too small and too conflicting to reliably confirm this.     

c-erbB-2 expression in breast cancer detected by immunoblotting and immunohistochemistry

Evidence that the c-erbB-2 proto-oncogene is important in prognosis and oncogenesis in a number of human malignancies is increasing. DNA (Southern) hybridization and immunoblotting (Western) techniques are most commonly utilized to determine the amplification and protein expression of this proto-oncogene, respectively. These extraction techniques are often time consuming, costly, and subject to variability depending on the histological characteristics of the tumor. Immunohistochemistry (IHC), on the other hand, is more often time and cost effective. In addition, IHC may offer enhanced sensitivity over extraction techniques because of the in situ nature of analysis. In data presented here, 71 cases of human mammary carcinoma were concomitantly assessed for c-erbB-2 gene copy number and oncoprotein expression by dilution DNA hybridization and IHC, respectively. In 65 (92%) of 71 cases, high-level expression was associated with gene amplification, whereas moderate or low-level expression was associated with a normal diploid gene copy number. In five of the six discrepant cases, IHC predicted amplification which was not corroborated by Southern analysis. In these cases, tumor mass was limited by the intraductal component of the lesion or by an abundance of stromal elements within the specimen. In 39 of the 71 total cases, Western immunoblotting was compared with IHC in the assessment of oncoprotein expression. Concordance was found in 33 (85%) of 39 cases. In four of the six discrepant cases, high levels of c-erbB-2 expression were demonstrated by IHC but not by immunoblotting. In these cases, intraductal disease and stroma-rich tumors again led to a relative paucity of neoplastic tissue within the specimens. We conclude that IHC offers a favorable alternative to either Southern analysis or Western immunoblotting in the assessment of c-erbB-2 gene copy number and expression levels of oncoprotein in human mammary carcinoma. Furthermore, IHC may prove advantageous to either extraction technique in specimens with limited tumor mass, such as biopsy materials, stroma-rich tumors, or early stage lesions such as intraductal carcinoma.     

Hormonal regulation of c-erbB-2 oncogene expression in breast cancer cells.

Expression of the c-erbB-2 (neu, HER-2) oncogene is found to be subjected to hormonal and developmental regulation in normal as well as neoplastic mammary cells. We have previously reported that estrogens inhibit c-erbB-2 expression at both the mRNA and protein level in estrogen receptor (ER)-positive, but not in ER-negative, breast cancer cell lines. Reversion of c-erbB-2 inhibition is seen with tamoxifen. The effect on c-erbB-2 expression of several other hormones and factors, which influence mammary cell growth and differentiation, has been studied. Our observations indicate that, in normal and neoplastic mammary cells, c-erbB-2 expression is inversely related to cell proliferation. While estrogens, anti-estrogens and cAMP clearly regulate c-erbB-2 mRNA levels, epidermal growth factor dramatically decreases the c-erbB-2 protein without affecting the level of c-erbB-2 mRNA. Therefore, different signals converging in terms of cell proliferation regulate c-erbB-2 expression by different molecular mechanisms.     

Overexpression of c-erbB-2 oncoprotein and associated pathobiological factors in invasive primary breast cancer

Breast cancer tissues from 271 cases were analyzed immunologically for c-erbB-2 oncoprotein (HER-2/neu), epidermal growth factor receptor (EGF-R) and estrogen receptor (ER). Overexpression of both c-erbB-2 oncoprotein and EGF-R showed an inverse association with ER and a direct association with metastatic involvement of lymph node and high histological grade. The frequency of c-erbB-2 and EGF-R overexpression was significantly higher among postmenopausal cases in comparison with premenopausal cases. Further, only in postmenopausal patients, c-erbB-2 oncoprotein (chi2 = 6.4, P < 0.05) and EGF-R (chi2 = 6.4, p < 0.05) as well as their concomitant expression (chi2 = 11.5, p < 0.01) revealed a statistically significant association with ER.     

Maspin and c-erbB-2 expression in correlation with microvessel density in invasive ductal breast cancer

Maspin is a unique member of the serpin family involved in regulation of cell migration, apoptosis and angiogenesis in breast and prostate cancers. In this study maspin expression in comparison with c-erbB-2 (HER2/neu) oncogene expression and microvessel density was investigated. The examined material included specimens of primary invasive ductal breast cancer derived from 69 patients. They were analyzed immunocytochemically to assess maspin and c-erbB-2 expression, as well as microvessel density using endothelium marker CD31. In the studied cancers, maspin expression in cancer cells was detected in more than half of the cases (50.73%). Although statistically insignificant (p=0.27), maspin expression showed decreasing tendency with the increase of tumor grade. C-erbB-2 oncogene expression was observed in 78.26% of the examined cancers. Statistically significant positive correlation was found between c-erbB-2 expression and tumor grade (p<0.005). Analysis of the dependence between maspin and c-erbB-2 expression exhibited statistically significant inverse correlation (p<0.001). Mean microvessel density (MVD) of the studied cancers was 71.64 (SD=19.36). MVD decreased with the increase of maspin expression, whereas in the cases showing c-erbB-2 overexpression MVD was clearly higher. Both correlations were statistically significant (p<0.005). In conclusion, it could be stated that increase in maspin expression is associated with weaker expression of c-erbB-2 oncogene and lower microvessel density, which implies a significant role of maspin in tumor biology. However, the exact mechanism of maspin action (including its potential role in angiogenesis), as well as the assessment of its prognostic significance in breast cancer require further studies.     

c-erbB-2/neu protein expression, DNA ploidy and S phase in breast cancer

Abstract. DNA content and c-erbB2/neu protein (p185) expression were evaluated by flow-cytometry and ELISA, respectively, in 166 specimens of primary breast cancer. A non-diploid DNA content was found in 88 tumours (53%), with the DNA index ranging from 0.7-2.7. S phase fraction (SPF) evaluation, performed in 130 cases, showed significantly higher values in aneuploid than in diploid tumours (median values, 17.3% and 5.8%, respectively). Thirty-six tumours (21.6%) showed p185 overexpression, while 45 (27.1%) and 85 (51.3%) showed intermediate and low expression, respectively. A good correlation ( P =0.0023) was found between DNA content and p185 positivity. Tumours with high p185 values were mainly aneuploid, while tumours with intermediate or low expression had variable degrees of DNA content. Furthermore, p185 concentration was significantly higher in aneuploid than in diploid tumours ( P =0.009). The highest rate of p185 (+) cases and the highest p185 concentrations occurred in triploid (1.3相似文献   

Immunometric assays of ras and c-erbB-2/neu overexpression in breast cancer: a pilot study

The expression of the ras and c-erbB2 oncoproteins (p21 and p185, respectively), together with estrogen receptor (ER) and progesterone receptor (PgR) determination, has been retrospectively analyzed in 68 primary breast carcinomas and in 19 normal breast tissue samples. The aims of this study were: a) to explore the association between ras and c-erbB2 expression; b) to evaluate the relationship between ras and c-erbB2 expression and both steroid receptor status and the classical clinical and pathological parameters; and c) to compare two different methods for p185 determination. p185 and p21 were measured by enzyme immunoassay (EIA); p185 was also determined by Western blotting (WB); ER and PgR were assayed by radioligand binding assay. The highest value of p185 in benign breast lesions was used as the threshold to distinguish between positive and negative samples. With this threshold the c-erbB2 oncoprotein was overexpressed in 41.2% (with EIA) and in 50% (with WB) of cancer samples. The concordance rate between the two methods was 79.4. No significant association was found between p21 and p185 levels either in cancer or in normal breast tissue samples. Increasing levels of tumor p21 were associated with a shorter time to recurrence and overall survival. Increasing levels of p185 were associated with a significantly shorter time to recurrence (p185 EIA: p = 0.04, p185 WB: p = 0.029) and overall survival (p185 EIA: p = 0.04, p185 WB: p = 0.029).     

A flow cytometric study of c-erbB-3 expression in breast cancer

In order to assess the specificity of biotinylated anti-c-erbB-3 antibody, screening was performed on a series of tumour cell lines and lymphocytes. Staining was found to be consistent, with good reproducibility. Twenty-nine consecutive breast cancer samples were obtained from women treated with tamoxifen and undergoing elective mastectomy. Twenty-eight invasive ductal carcinomas and 1 DCIS were stained for c-erbB-3 expression: 2 were grade I (Bloom and Richardson), 15 grade II, and 11 grade III tumours, 1 being unclassified; 16 were axillary node positive and 10 node negative; in 2 cases no nodes were sampled. Tumours examined by flow cytometry were stained with cytokeratin FITC antibody and the cytokeratin-positive population gated. Using Mann-Whitney analysis no association was seen between c-erbB-3 expression and Bloom and Richardson grade or axillary node status. In the tumour samples c-erbB-3 expression was found to show an association with EGF-R (P=0.021r ²=0.16), PgR (P=0.02,r ²=0.16), c-myc (P<0.0001,r ²=0.5), c-jun (P=0.001,r ²=0.4) and c-fos (P=0.001,r ²=0.5) but not with c-erbB-2 (P=0.2,r ²=0.06), ER (P=0.4,r ²=0.02) or p53 1801 (P=0.05,r ²=0.2). Expression of c-erbB-3 may not be an independent marker of prognosis, but it is associated with other markers of poor prognosis and early cellular events linked with aberrant growth and differentiation.This study was supported by The North of England Cancer Research Campaign     

Posttranscriptional suppression of proto-oncogene c-fms expression by vigilin in breast cancer

cis-acting elements found in 3'-untranslated regions (UTRs) are regulatory signals determining mRNA stability and translational efficiency. By binding a novel non-AU-rich 69-nucleotide (nt) c-fms 3' UTR sequence, we previously identified HuR as a promoter of c-fms proto-oncogene mRNA. We now identify the 69-nt c-fms mRNA 3' UTR sequence as a cellular vigilin target through which vigilin inhibits the expression of c-fms mRNA and protein. Altering association of either vigilin or HuR with c-fms mRNA in vivo reciprocally affected mRNA association with the other protein. Mechanistic studies show that vigilin decreased c-fms mRNA stability. Furthermore, vigilin inhibited c-fms translation. Vigilin suppresses while HuR encourages cellular motility and invasion of breast cancer cells. In summary, we identified a competition for binding the 69-nt sequence, through which vigilin and HuR exert opposing effects on c-fms expression, suggesting a role for vigilin in suppression of breast cancer progression.     

The RET proto-oncogene: a potential target for molecular cancer therapy

The inhibition of activated receptor tyrosine kinases has defined a new era of selective cancer therapy. The value of these approaches has been demonstrated for a growing number of tyrosine kinases. Gain-of-function alterations within the RET proto-oncogene are responsible for the development of medullary, as well as papillary, thyroid carcinoma and make it a candidate for the design of targeted therapies. Recently, various strategies have been used to block the activity of RET in pre-clinical models, providing evidence that RET is a potential target for a selective cancer-therapy approach, especially when considering that the inhibition of RET activity is sufficient to revert neoplastic characteristics. Although the ideal clinically useful therapeutic option has yet to be developed, successes with other selective tyrosine kinase inhibitors encourages further effort.     

Mucins in the pathogenesis of breast cancer: implications in diagnosis, prognosis and therapy

Mucins are high molecular weight, multifunctional glycoproteins comprised of two structural classes-the large transmembrane mucins and the gel-forming or secreted mucins. The primary function of mucins is to protect and lubricate the luminal surfaces of epithelium-lined ducts in the human body. Recent studies have identified a differential expression of both membrane bound (MUC1, MUC4 and MUC16) and secreted mucins (MUC2, MUC5AC, MUC5B and MUC6) in breast cancer tissues when compared with the non-neoplastic breast tissues. Functional studies have also uncovered many unique roles of mucins during the progression of breast cancer, which include modulation in proliferative, invasive and metastatic potential of tumor cells. Mucins function through many unique domains that can form complex association with various signaling molecules including growth factor receptors and intercellular adhesion molecules. While there is growing information about mucins in various malignancies including breast cancer, no focused review is there on the expression and functional roles of mucins in breast cancer. In this present review, we have discussed the differential expression and functional roles of mucins in breast cancer. The potential of mucins as diagnostic and prognostic markers and as therapeutic targets in breast cancer have also been discussed.     

Overexpression of the c-erbB-2 protein in human breast tumor cell lines

The c-erbB-2 proto-oncogene is amplified in a high percentage of primary human breast tumors, suggesting that the overexpression of this gene may be involved in the development of human breast cancer. We have investigated five human breast tumor cell lines and have detected amplified c-erbB-2 gene copies in two of them. This amplification leads to overexpression of the c-erbB-2 protein. In addition, two other cell lines have elevated protein levels without gene amplification, suggesting that other mechanisms can lead to overexpression of the c-erbB-2 protein. These results are similar to those that we obtained during a study of primary breast tumors (Berger et al.: Cancer Res 48:1238-1243, 1988). These breast tumor cell lines should be useful for an analysis of c-erbB-2 expression and of the mechanisms that in some cases lead to overexpression.     

Development and characterization of breast carcinoma cell lines as in vitro and in vivo models for breast cancer diagnosis and therapy

Summary To establish a model system for preclinical radioimmunotherapy studies, attempts were made to graft 16 different human breast carcinoma cell lines into BALB/c nu/nu (nude) mice. Nine produced serially transplantable tumors growing at a variable rate, whereas seven failed to do so. Conversely, three new cell lines were established in monolayer culture from transplantable human breast tumors in nude mice. Twelve selected tumors and their corresponding cell lines were characterized for DNA ploidy, % S-phase, and breast epithelial mucin expression by immunohistochemistry and flow cytometry. A wide diversity of these cellular characteristics were found in that each tumor was unique and distinct from the others. DNA ploidy differed among the tumors but was not affected by switching between in vitro to in vivo growth. Some tumors expressed similar levels of the breast mucin both in vitro and in vivo, whereas most expressed lower levels as transplantable tumors. There was a good correlation between immunohistochemical and flow cytometric determination of surface and cytoplasmic mucin expression, and with both techniques estrogen and progesterone receptor positive tumors had significantly higher levels of mucin expression than receptor negative tumors. These 12 transplantable breast tumors, with their corresponding cell lines, provide an excellent model system for testing radioimmunotherapy and other therapeutic reagents because they exhibit diverse phenotypic characteristics that represented a mini-population of breast cancer patients’ tumors, allowing assessment of the effect of therapy when confronted with different breast tumors’ genotype and phenotype.     

Anti-HER2 vaccines: new prospects for breast cancer therapy

Each year, breast cancer accounts for more than 400,000 new cancer cases and more than 130,000 cancer deaths in Europe. Prognosis of nonmetastatic breast cancer patients is directly related to the extent of the disease, mainly nodal spreading and tumor size, and to the molecular profile, particularly HER2 over-expression. In patients with HER2-over-expressing tumors, different studies have shown cellular and/or humoral immune responses against HER2 associated with a lower tumor development at early stages of the disease. These findings have led to the hypothesis that the generation of an anti-HER2 immune response should protect patients from HER2-over-expressing tumor growth. Taken together with the clinical efficiency of trastuzumab-based anti-HER2 passive immunotherapy, these observations allowed to envisage various vaccine strategies against HER2. The induction of a stable and strong immunity by cancer vaccines is expected to lead to establishment of immune memory, thereby preventing tumor recurrence. However, an immunological tolerance against HER2 antigen exists representing a barrier to effective vaccination against this oncoprotein. As a consequence, the current challenge for vaccines is to find the best conditions to break this immunological tolerance. In this review, we will discuss the different anti-HER2 vaccine strategies currently developed; considering the strategies having reached the clinical phases as well as those still in preclinical development. The used antigen can be either composed of tumoral allogenic cells or autologous cells, or specific to HER2. It can be delivered by dendritic cells or in a DNA, peptidic or proteic form. Another area of research concerns the use of anti-idiotypic antibodies mimicking HER2.     

Perspectives for the hormonal therapy of breast cancer

The role of estrogens, including its sources, tissue distribution, metabolism, and mechanism of action, is discussed in this review. The ER alpha and beta are functioning separately, and there is a physiological balance between their activity. Whenever this balance is over thrown due to endogenous or exogenous carcinogenic factors, malignancy develops. Risk factors of breast cancer are listed and evaluated individually. It should be stressed however, that their carcinogenic effect sums up. The knowledge of established risk factors rises the possibility of chemoprevention, which might be highly desirable in case of gene carriers. Special emphasis is attached to the SERM molecules which act as antiestrogens. Their antitumour effect is largely used in the treatment of hormone sensitive advanced breast cancer patients, and their efficacy has been proved in adjuvant therapy as well. Their preventive use might also be justified, especially in gene carriers. Aromatase inhibitors form a special class among the SERM molecules. In Hungary, anastrozole, letrozole and exemestane are widely applied for the therapy of breast cancer patients, while raloxifene has only been introduced recently, mainly in order to prevent osteoporosis. The therapeutic value of fulvestrant is unknown yet and its antitumour effect has to be explored. The therapeutic significance of these molecules lies in the fact that they might be effective after the development of tamoxifen resistance. There are several explanations for this phenomenon offering new targets for the further development of a succesful antitumour chemotherapy.     

The relationship between flow-cytometric and immunohistochemically detected c-erbB-2 expression,grade and DNA ploidy in breast cancer

Quantification of c-erb B-2 and its relationship with other prognostic markers using flow cytometry has been examined. In this study a level for c-erb B-2 expression above which tumours are classified as positive by flow cytometry has been determined by employment of positive cut-off threshold levels. c-erb B-2 expression by both flow cytometry and immunohistochemistry was studied using the monoclonal antibody NCL-CBII. The relationship of c-erb B-2 quantification by flow cytometry was then compared with ploidy, axillary node status, tumour size and grade. Increased c-erb B-2 expression was seen using flow cytometry. Correlation between immunohistochemistry and flow-cytometry methods just failed to reach significance (P=0.06). Immunohistochemistry revealed a significant relationship between c-erb B-2 expression and aneuploidy (P=0.04). Cytokeratinpositive cells from 110 samples obtained from patients with breast cancer were assayed for DNA content and c-erb B-2 expression by flow cytometry. No correlation was seen between these parameters upon application of Mann Whitney analysis. However, examination of fluorescence thresholds showed a positive correlation between grade and c-erb B-2 expression at a level of more than 3200 molecules (P0.03). At the level of 3600 molecules significance was increased (P=0.004). These levels equated with between 15% and 19% of the samples being classified as c-erb B-2 positive. Application of these cut-off points showed no correlation between c-erb B-2 expression and ploidy, tumour size or axillary node status. Comparison of ploidy and grade showed a significant association (P=0.0015), increased grade correlating with aneuploidy.     

An epigenomic approach to therapy for tamoxifen-resistant breast cancer

Tamoxifen has been a frontline treatment for estrogen receptor alpha (ERα)-positive breast tumors in premenopausal women. However, resistance to tamoxifen occurs in many patients. ER still plays a critical role in the growth of breast cancer cells with acquired tamoxifen resistance, suggesting that ERα remains a valid target for treatment of tamoxifen-resistant (Tam-R) breast cancer. In an effort to identify novel regulators of ERα signaling, through a small-scale siRNA screen against histone methyl modifiers, we found WHSC1, a histone H3K36 methyltransferase, as a positive regulator of ERα signaling in breast cancer cells. We demonstrated that WHSC1 is recruited to the ERα gene by the BET protein BRD3/4, and facilitates ERα gene expression. The small-molecule BET protein inhibitor JQ1 potently suppressed the classic ERα signaling pathway and the growth of Tam-R breast cancer cells in culture. Using a Tam-R breast cancer xenograft mouse model, we demonstrated in vivo anti-breast cancer activity by JQ1 and a strong long-lasting effect of combination therapy with JQ1 and the ER degrader fulvestrant. Taken together, we provide evidence that the epigenomic proteins BRD3/4 and WHSC1 are essential regulators of estrogen receptor signaling and are novel therapeutic targets for treatment of Tam-R breast cancer.     

Dissecting resistance to endocrine therapy in breast cancer

Drugs that target the reliance of tumour cells upon estrogen signalling have revolutionised the treatment of breast cancer. Despite this, resistance to these endocrine therapies limits their utility. While the study of individual genes has contributed greatly to understanding drug resistance, relatively unbiased screening approaches may also be illuminating. The results of a high-throughput RNA interference screen identifying novel determinants of tamoxifen resistance support this conjecture and demonstrate that such approaches can identify clinically relevant genes, such as CDK10.