Oncogene amplification and prognosis in breast cancer: relationship with systemic treatment

Chaperonin-Containing TCP1 Complex (CCT) Promotes Breast Cancer Growth Through Correlations With Key Cell Cycle Regulators

Uncontrolled proliferation as a result of dysregulated cell cycling is one of the hallmarks of cancer. Therapeutically targeting pathways that control the cell cycle would improve patient outcomes. However, the development of drug resistance and a limited number of inhibitors that target multiple cell cycle modulators are challenges that impede stopping the deregulated growth that leads to malignancy. To advance the discovery of new druggable targets for cell cycle inhibition, we investigated the role of Chaperonin-Containing TCP1 (CCT or TRiC) in breast cancer cells. CCT, a type II chaperonin, is a multi-subunit protein-folding complex that interacts with many oncoproteins and mutant tumor suppressors. CCT subunits are highly expressed in a number of cancers, including breast cancer. We found that expression of one of the CCT subunits, CCT2, inversely correlates with breast cancer patient survival and is subject to copy number alterations through genomic amplification. To investigate a role for CCT2 in the regulation of the cell cycle, we expressed an exogenous CCT2-FLAG construct in T47D and MCF7 luminal A breast cancer cells and examined cell proliferation under conditions of two-dimensional (2D) monolayer and three-dimensional (3D) spheroid cultures. Exogenous CCT2 increased the proliferation of cancer cells, resulting in larger and multiple spheroids as compared to control cells. CCT2-expressing cells were also able to undergo spheroid growth reversal, re-attaching, and resuming growth in 2D cultures. Such cells gained anchorage-independent growth. CCT2 expression in cells correlated with increased expression of MYC, especially in spheroid cultures, and other cell cycle regulators like CCND1 and CDK2, indicative of a novel activity that could contribute to the increase in cell growth. Statistically significant correlations between CCT2, MYC, and CCND1 were shown. Since CCT2 is located on chromosome 12q15, an amplicon frequently found in soft tissue cancers as well as breast cancer, CCT2 may have the basic characteristics of an oncogene. Our findings suggest that CCT2 could be an essential driver of cell division that may be a node through which pathways involving MYC, cyclin D1 and other proliferative factors could converge. Hence the therapeutic inhibition of CCT2 may have the potential to achieve multi-target inhibition, overcoming the limitations associated with single agent inhibitors.

Discovery and optimization of novel pyrazole-benzimidazole CPL304110, as a potent and selective inhibitor of fibroblast growth factor receptors FGFR (1-3)

The FGFR family is characterized by four receptors (FGFR 1-4), binding to 18 ligands called fibroblast growth factors (FGFs). Aberrant activation of FGFs and their FGFRs has been implicated in a broad spectrum of human tumors. We employed the scaffolds hybridization approach, scaffold-hopping concept to synthesize a series of novel pyrazole-benzimidazole derivatives 56 (a-x). Compound 56q (CPL304110) was identified as a selective and potent pan-FGFR inhibitor for FGFR1, -2, -3 with IC₅₀s of 0.75 nM, 0.50 nM, 3.05 nM respectively, whereas IC₅₀ of 87.90 nM for FGFR4. Due to its favorable pharmacokinetic profile, low toxicity and potent anti-tumor activity in vivo, compound 56q is currently under evaluation in phase I clinical trial for the treatment of bladder, gastric and squamous cell lung cancers (01FGFR2018; NCT04149691).

Nuclear action of FGF members in endocrine-related tissues and cancer: Interplay with steroid receptor pathways

Dysregulation of the fibroblast growth factors/fibroblast growth factor receptor (FGF/FGFR) pathway has been implicated in a wide range of human disorders and several members have been localized in the nuclear compartment. Hormone-activated steroid receptors or ligand independent activated receptors form nuclear complexes that activate gene transcription. This review aims to highlight the interplay between the steroid receptor and the FGF/FGFR pathways and focuses on the current knowledge on nuclear action of FGF members in endocrine-related tissues and cancer. The nuclear trafficking and targets of FGF/FGFR members and the available evidence on the interplay with steroid hormones and receptors is described. Finally, the data on aberrant FGF/FGFR signaling is summarized and the nuclear action of FGF members on endocrine resistant breast cancer is highlighted. Identifying the mechanisms underlying FGF-induced endocrine resistance will be important to understand how to efficiently target endocrine-related diseases and even enhance or restore endocrine sensitivity in hormone receptor positive tumors.

Addition of anti-estrogen therapy to anti-HER2 dendritic cell vaccination improves regional nodal immune response and pathologic complete response rate in patients with ERpos/HER2pos early breast cancer

HER2-directed therapies are less effective in patients with ERpos compared to ERneg breast cancer, possibly reflecting bidirectional activation between HER2 and estrogen signaling pathways. We investigated dual blockade using anti-HER2 vaccination and anti-estrogen therapy in HER2pos/ERpos early breast cancer patients. In pre-clinical studies of HER2pos breast cancer cell lines, ERpos cells were partially resistant to CD4+ Th1 cytokine-induced metabolic suppression compared with ERneg cells. The addition of anti-estrogen treatment significantly enhanced cytokine sensitivity in ERpos, but not ERneg, cell lines. In two pooled phase-I clinical trials, patients with HER2pos early breast cancer were treated with neoadjuvant anti-HER2 dendritic cell vaccination; HER2pos/ERpos patients were treated with or without concurrent anti-estrogen therapy. The anti-HER2 Th1 immune response measured in the peripheral blood significantly increased following vaccination, but was similar across the three treatment groups (ERneg vaccination alone, ERpos vaccination alone, ERpos vaccination + anti-estrogen therapy). In the sentinel lymph nodes, however, the anti-HER2 Th1 immune response was significantly higher in ERpos patients treated with combination anti-HER2 vaccination plus anti-estrogen therapy compared to those treated with anti-HER2 vaccination alone. Similar rates of pathologic complete response (pCR) were observed in vaccinated ERneg patients and vaccinated ERpos patients treated with concurrent anti-estrogen therapy (31.4% vs. 28.6%); both were significantly higher than the pCR rate in vaccinated ERpos patients who did not receive anti-estrogen therapy (4.0%, p = 0.03). Since pCR portends long-term favorable outcomes, these results support additional clinical investigations using HER2-directed vaccines in combination with anti-estrogen treatments for ERpos/HER2pos DCIS and invasive breast cancer.

Improved drug delivery and therapeutic efficacy of PEgylated liposomal doxorubicin by targeting anti-HER2 peptide in murine breast tumor model

Targeted cancer therapy is a powerful therapeutic strategy to management of cancer. HER2 as an anticancer target has long been studied. Its overexpression plays an important role in the pathogenesis and progressiveness of breast and other cancers. To establish efficient and reliable drug delivery to HER2-overexpressing cells, the authors of this study have developed anti-HER2 (ErbB2) peptide-liposomal formulations of doxorubicin (DOX) by an engineered breast tumor-targeting peptide ligand, AHNP, Anti-HER2/neu peptide, (FCDGFYACYADV) with three glycine amino acids as spacer before its original sequencing. Towards this goal, PEGylated liposome doxorubicin (PLD) bearing different ligand densities of AHNP was prepared and characterized for their size, zeta potential and peptide conjugation. The AHNP functionalization and density effects on breast tumor cell uptake, selective cytotoxicity, prevention of tumor growth and the tissue biodistribution of encapsulated DOX were studied in mice bearing TUBO breast cancer tumor model. The findings demonstrated that increasing the ligand density of AHNP increases cytotoxicity and cell-uptake in SKBR3 and TUBO cells which overexpress HER2 but not in MDA-MB-231with low HER2 expression profile. The anticancer activity was also superior for targeted liposomal DOX with more AHNP densities. Overall, the results showed that optimum AHNP density functionalization of PLD can significantly improve selectivity and the therapeutic index of liposomal DOX in the treatment of HER2 positive breast cancer and merits further investigation.

The Lifetime Economic Burden of Inaccurate HER2 Testing: Estimating the Costs of False-Positive and False-Negative HER2 Test Results in US Patients with Early-Stage Breast Cancer

BACKGROUND

Patients with breast cancer whose tumors test positive for human epidermal growth factor receptor 2 (HER2) are treated with HER2-targeted therapies such as trastuzumab, but limitations with HER2 testing may lead to false-positive (FP) or false-negative (FN) results.

OBJECTIVES

To develop a US-level model to estimate the effect of tumor misclassification on health care costs and patient quality-adjusted life-years (QALYs).

METHODS

Decision analysis was used to estimate the number of patients with early-stage breast cancer (EBC) whose HER2 status was misclassified in 2012. FP results were assumed to generate unnecessary trastuzumab costs and unnecessary cases of trastuzumab-related cardiotoxicity. FN results were assumed to save money on trastuzumab, but with a loss of QALYs and greater risk of disease recurrence and its associated costs. QALYs were valued at $100,000 under a net monetary benefit approach.

RESULTS

Among 226,870 women diagnosed with EBC in 2012, 3.12% (n = 7,070) and 2.18% (n = 4,955) were estimated to have had FP and FN test results, respectively. Approximately 8400 QALYs (discounted, lifetime) were lost among women not receiving trastuzumab because of FN results. The estimated incremental per-patient lifetime burden of FP or FN results was $58,900 and $116,000, respectively. The implied incremental losses to society were $417 million and $575 million, respectively.

CONCLUSIONS

HER2 tests result in misclassification and nonoptimal treatment of approximately 12,025 US patients with EBC annually. The total economic societal loss of nearly $1 billion suggests that improvements in HER2 testing accuracy are needed and that further clinical and economic studies are warranted.

Preoperative serum HER2 extracellular domain levels in primary invasive breast cancer

Background

Despite the preclinical outcomes and biologic significance of the presence of the human epidermal growth factor receptor-2 (HER2) extracellular domain (ECD), there is little evidence supporting the measurement of ECD levels in any clinical setting. The aim of this study was to determine the prevalence of elevated serum HER2 ECD levels, the association between these levels and tissue HER2 overexpression, and the potential clinical prognostic value of HER2 ECD in primary invasive breast cancer.

Methods

Serum HER2 ECD levels were examined preoperatively in 2,862 consecutive stage I–III primary breast cancer patients between 2007 and 2009. Serum HER2 ECD levels were measured by chemiluminescence immunoassay (ADVIA Centaur), and the tissue HER2 status was assessed by immunohistochemistry and fluorescence in situ hybridization. The cutoff value for the serum level of HER2 ECD was set at 15.2 ng/ml.

Results

Among the 2,862 patients, 126 (4.4%) had elevated serum HER2 ECD levels, and HER2 was overexpressed in the tumor tissue of 692 patients (24.2%), with a concordance of 78.7%. Multivariate analysis revealed that elevated serum HER2 ECD was a significant independent prognostic factor for worse distant-metastasis-free survival [DMFS; hazard ratio (HR) = 2.50, 95% confidence interval (CI) = 1.5–4.3, P = 0.001] and breast-cancer-specific survival (BCSS; HR = 2.0, 95% CI = 1.1–3.8, P = 0.036), which were much stronger in patients with tissue HER2-positive tumors (DMFS: HR = 3.8, 95% CI = 2.0–7.0, P < 0.001; BCSS: HR = 2.6, 95% CI = 1.2-5.3, P = 0.012).

Conclusions

Given the prevalence of HER2 expression, its measurement as an independent prognostic factor can be clinically useful, particularly in patients with tissue HER2-positive tumors.

Prognostic and predictive value of copy number alterations in invasive breast cancer as determined by multiplex ligation-dependent probe amplification

BACKGROUND

Breast cancer is a leading cause of morbidity and mortality in women worldwide. About 70 % of breast cancers are estrogen receptor (ER) positive. Blocking estrogen action by tamoxifen has been the treatment of choice in ER positive breast cancers for more than 30 years. In the past, several studies have revealed associations between gene copy number alterations and responsiveness to tamoxifen therapy, but so far no single gene copy number alteration could completely explain the response variation observed between individual breast cancer patients. Here, we set out to perform a simultaneous analysis of copy number alterations of several genes involved in the prognosis and response to therapy by multiplex ligation-dependent probe amplification (MLPA).

METHODS

A case-control study was designed encompassing 170 non-metastatic ER positive breast cancer patients (case group = 85, control group = 85). All patients in the control group had received standard adjuvant tamoxifen treatment for 5 years without any evidence of recurrence. Patients in the case group had experienced early recurrences while receiving tamoxifen treatment. 76 % of the patients of the case group and 73 % of the patients of the control group had received anthracycline-based adjuvant chemotherapy. Gene copy number alterations detected by MLPA in both groups were compared.

RESULTS

Amplification of CCND1 (OR = 3.13; 95 % CI = 1.35 to 7.26; p = 0.006) and TOP2A (OR = 3.05; 95 % CI = 1.13 to 8.24; p = 0.022) were significantly more prevalent in the case group, compared to the control group. In a multivariate analysis CCND1 (p = 0.01) and TOP2A (p = 0.041) amplifications remained significant predictors of recurrence.

CONCLUSIONS

Our results indicate that CCND1 amplification may serve as a useful biomarker for hormone responsiveness, and that TOP2A amplification may serve as a useful prognostic biomarker.

Potential Predictive Factors for Response to Weekly Paclitaxel Treatment in Patients with Metastatic Breast Cancer

The authors compare results obtained from weekly paclitaxel treatment in advanced breast cancer patients with biological and clinical prognostic factors. Expression of c-erbB-2, Ki-67, p53 and hormone receptors (HR) was examined by immunohistochemistry in samples of breast tissue from 30 patients. Univariate analysis showed that Ki-67 positivity and low performance status (PS) were associated with poor outcome (P <0.05). We observed that expression of p53 and c-erbB-2 did not have any negative effect on response to chemotherapy and survival. HR-negative patients had better response and slightly statistically significant overall survival (OS) rates compared to HR-positive patients (P >0.05). In a multivariate analysis low PS was the only significant predictor of shorter survival (P <0.05). In conclusion, while the expression of p53 and c-erbB-2 did not have any effect on treatment results, negative Ki-67 expression and negative HR status were associated with better OS in this patient population. PS was the only significant predictor for OS.

Poor-prognosis estrogen receptor- positive disease: present and future clinical solutions

Use of chemotherapy for patients with estrogen receptor (ER)-positive breast cancer has been a conflicting issue. Recent studies have identified predictive markers allowing identification of poor-prognosis ER-positive breast cancers in need of more aggressive therapy. In general, tumours belonging to the so-called luminal B class, tumours expressing a high Ki67, human epidermal growth factor receptor 2 (HER-2) overexpression or a high score on the Oncotype DX gene expression profile reveal a poor prognosis compared with ER-rich tumours of the luminal A class. In contrast, recent studies have shown these tumours, contrasting tumours of the luminal A class, to benefit from more aggressive anthracycline-containing chemotherapy including a taxane. In the case of metastatic disease, patients with HER-2-positive, ER-positive tumours may benefit from having endocrine therapy and an anti-HER-2 agent administered in combination.

High serum HER2 extracellular domain levels: correlation with a worse disease-free survival and overall survival in primary operable breast cancer patients

PURPOSE

High serum human epidermal growth factors receptor-2 (HER2) extracellular domain (ECD) has been identified as an independent prognostic indicator of poor prognosis in metastatic breast cancer. However, its prognostic value in primary operable breast cancer was still controversial. We aim to investigate the correlation between serum HER2 ECD levels and tissue HER2 status, the association between serum HER2 ECD levels and clinicopathological characteristics, and their impacts on disease-free survival (DFS) and overall survival (OS) in primary operable breast cancer.

METHODS

Two hundred and fifty-two primary operable breast cancer patients pretreated from 2002 to 2009 in Sun Yat-Sen University Cancer Center were enrolled in this study. Serum HER2 ECD was measured by chemiluminescent assay, and tissue HER2 status was accessed by immunohistochemistry (IHC) and fluorescent in situ hybridization (FISH) assay.

RESULTS

There was a significant correlation between serum HER2 ECD levels and HER2 tissue status (P < 0.001, R = 0.36). High serum HER2 ECD levels (≥15 ng/mL) were significantly associated with age (≥35 years) (P = 0.028), postmenopausal status (P < 0.001), stage III (P < 0.001), tumor size (≥2 cm) (P < 0.001), lymph node involvement (P < 0.001), negative estrogen receptor (P = 0.005), and progesterone receptor status (P = 0.001). Multivariate analysis showed that high serum HER2 ECD level was an independent prognostic factor of worse DFS (P = 0.014) and OS (P = 0.014) in primary operable breast cancer patients.

CONCLUSION

Serum HER2 ECD level can reflect tissue HER2 status and can be an independent prognostic indicator for primary operable breast cancer patients.

Cyclin D1, Id1 and EMT in breast cancer

Background

Cyclin D1 is a well-characterised cell cycle regulator with established oncogenic capabilities. Despite these properties, studies report contrasting links to tumour aggressiveness. It has previously been shown that silencing cyclin D1 increases the migratory capacity of MDA-MB-231 breast cancer cells with concomitant increase in 'inhibitor of differentiation 1' (ID1) gene expression. Id1 is known to be associated with more invasive features of cancer and with the epithelial-mesenchymal transition (EMT). Here, we sought to determine if the increase in cell motility following cyclin D1 silencing was mediated by Id1 and enhanced EMT-features. To further substantiate these findings we aimed to delineate the link between CCND1, ID1 and EMT, as well as clinical properties in primary breast cancer.

Methods

Protein and gene expression of ID1, CCND1 and EMT markers were determined in MDA-MB-231 and ZR75 cells by western blot and qPCR. Cell migration and promoter occupancy were monitored by transwell and ChIP assays, respectively. Gene expression was analysed from publicly available datasets.

Results

The increase in cell migration following cyclin D1 silencing in MDA-MB-231 cells was abolished by Id1 siRNA treatment and we observed cyclin D1 occupancy of the Id1 promoter region. Moreover, ID1 and SNAI2 gene expression was increased following cyclin D1 knock-down, an effect reversed with Id1 siRNA treatment. Similar migratory and SNAI2 increases were noted for the ER-positive ZR75-1 cell line, but in an Id1-independent manner. In a meta-analysis of 1107 breast cancer samples, CCND1^low/ID1^high tumours displayed increased expression of EMT markers and were associated with reduced recurrence free survival. Finally, a greater percentage of CCND1^low/ID1^high tumours were found in the EMT-like 'claudin-low' subtype of breast cancer than in other subtypes.

Conclusions

These results indicate that increased migration of MDA-MB-231 cells following cyclin D1 silencing can be mediated by Id1 and is linked to an increase in EMT markers. Moreover, we have confirmed a relationship between cyclin D1, Id1 and EMT in primary breast cancer, supporting our in vitro findings that low cyclin D1 expression can be linked to aggressive features in subgroups of breast cancer.

Discovery of 3-(2,6-dichloro-3,5-dimethoxy-phenyl)-1-{6-[4-(4-ethyl-piperazin-1-yl)-phenylamino]-pyrimidin-4-yl}-1-methyl-urea (NVP-BGJ398), a potent and selective inhibitor of the fibroblast growth factor receptor family of receptor tyrosine kinase

A novel series of N-aryl-N'-pyrimidin-4-yl ureas has been optimized to afford potent and selective inhibitors of the fibroblast growth factor receptor tyrosine kinases 1, 2, and 3 by rationally designing the substitution pattern of the aryl ring. On the basis of its in vitro profile, compound 1h (NVP-BGJ398) was selected for in vivo evaluation and showed significant antitumor activity in RT112 bladder cancer xenografts models overexpressing wild-type FGFR3. These results support the potential therapeutic use of 1h as a new anticancer agent.

Characterization of BCAR4, a novel oncogene causing endocrine resistance in human breast cancer cells

Resistance to the antiestrogen tamoxifen remains a major problem in the management of estrogen receptor-positive breast cancer. Knowledge on the resistance mechanisms is needed to develop more effective therapies. Breast cancer antiestrogen resistance 4 (BCAR4) was identified in a functional screen for genes involved in tamoxifen resistance. BCAR4 is expressed in 27% of primary breast tumors. In patients treated with tamoxifen for metastized disease high BCAR4 mRNA levels are associated with reduced clinical benefit and progression-free survival. Regarding tumor aggressiveness high BCAR4 mRNA levels are associated with a shorter metastasis free survival and overall survival. In the present study, we investigated the role of BCAR4 in endocrine resistance. Forced expression of BCAR4 in human ZR-75-1 and MCF7 breast cancer cells resulted in cell proliferation in the absence of estrogen and in the presence of various antiestrogens. Inhibition of estrogen receptor 1 (ESR1) expression with small interfering RNA (siRNA), implied that the BCAR4-induced mechanism of resistance is independent of ESR1. Highly conserved BCAR4 homologues of rhesus monkey, green monkey, and the less conserved common marmoset gene induced tamoxifen-resistant cell proliferation, in contrast to the distant BCAR4 homologues of bovine and rabbit. Injection of BCAR4-expressing ZR-75-1 cells into nude mice resulted in rapidly growing tumors. In silico analysis showed that BCAR4 mRNA is highly expressed in human placenta and oocyte, and absent in other normal tissues. In conclusion, BCAR4 is a strong transforming gene causing estrogen-independent growth and antiestrogen resistance, and induces tumor formation in vivo. Due to its restricted expression, BCAR4 may be a good target for treating antiestrogen-resistant breast cancer.

Relevance of BCAR4 in tamoxifen resistance and tumour aggressiveness of human breast cancer

Background:

Breast cancer anti-oestrogen resistance 4 (BCAR4) was identified in a search for genes involved in anti-oestrogen resistance in breast cancer. We explored whether BCAR4 is predictive for tamoxifen resistance and prognostic for tumour aggressiveness, and studied its function.

Methods:

BCAR4 mRNA levels were measured in primary breast tumours, and evaluated for association with progression-free survival (PFS) and clinical benefit in patients with oestrogen receptor (ERα)-positive tumours receiving tamoxifen as first-line monotherapy for advanced disease. In a separate cohort of patients with lymph node-negative, ERα-positive cancer, and not receiving systemic adjuvant therapy, BCAR4 levels were evaluated for association with distant metastasis-free survival (MFS). The function of BCAR4 was studied with immunoblotting and RNA interference in a cell model.

Results:

Multivariate analyses established high BCAR4 mRNA levels as an independent predictive factor for poor PFS after start of tamoxifen therapy for recurrent disease. High BCAR4 mRNA levels were associated with poor MFS and overall survival, reflecting tumour aggressiveness. In BCAR4-expressing cells, phosphorylation of v-erb-b2 erythroblastic leukaemia viral oncogene homolog (ERBB)2, ERBB3, and their downstream mediators extracellular signal-regulated kinase 1/2 and v-akt murine thymoma viral oncogene homolog (AKT) 1/2, was increased. Selective knockdown of ERBB2 or ERBB3 inhibited proliferation, confirming their role in BCAR4-induced tamoxifen resistance.

Conclusion:

BCAR4 may have clinical relevance for tumour aggressiveness and tamoxifen resistance. Our cell model suggests that BCAR4-positive breast tumours are driven by ERBB2/ERBB3 signalling. Patients with such tumours may benefit from ERBB-targeted therapy.

ZNF217, a candidate breast cancer oncogene amplified at 20q13, regulates expression of the ErbB3 receptor tyrosine kinase in breast cancer cells

Understanding the mechanisms underlying ErbB3 overexpression in breast cancer will facilitate the rational design of therapies to disrupt ErbB2-ErbB3 oncogenic function. Although ErbB3 overexpression is frequently observed in breast cancer, the factors mediating its aberrant expression are poorly understood. In particular, the ErbB3 gene is not significantly amplified, raising the question as to how ErbB3 overexpression is achieved. In this study we showed that the ZNF217 transcription factor, amplified at 20q13 in ∼20% of breast tumors, regulates ErbB3 expression. Analysis of a panel of human breast cancer cell lines (n = 50) and primary human breast tumors (n = 15) showed a strong positive correlation between ZNF217 and ErbB3 expression. Ectopic expression of ZNF217 in human mammary epithelial cells induced ErbB3 expression, whereas ZNF217 silencing in breast cancer cells resulted in decreased ErbB3 expression. Although ZNF217 has previously been linked with transcriptional repression because of its close association with C-terminal-binding protein (CtBP)1/2 repressor complexes, our results show that ZNF217 also activates gene expression. We showed that ZNF217 recruitment to the ErbB3 promoter is CtBP1/2-independent and that ZNF217 and CtBP1/2 have opposite roles in regulating ErbB3 expression. In addition, we identify ErbB3 as one of the mechanisms by which ZNF217 augments PI-3K/Akt signaling.

Mammary gland growth factors: roles in normal development and in cancer

Normal development of the mammary gland proceeds via interactions between the epithelium and the mesenchyme that start during embryogenesis and continue during pubertal outgrowth and differentiation. The function of specific peptide growth factors that bind members of the receptor tyrosine kinase family and the cytokine receptor family are required at each stage. In many cases the peptides are produced in one compartment and act on receptors in the other compartment. One of the striking differences between normal development and cancer is the loss of this cross-talk. Mammary tumor cells often produce a peptide and express the receptor on the same cell leading to autocrine activation of signaling pathways, a mechanism that is characteristic for cancer cells. We will discuss different peptides in the context of normal development and cancer in this review.

Classical and Novel Prognostic Markers for Breast Cancer and their Clinical Significance

The use of biomarkers ensures breast cancer patients receive optimal treatment. Established biomarkers such as estrogen receptor (ER) and progesterone receptor (PR) have been playing significant roles in the selection and management of patients for endocrine therapy. HER2 is a strong predictor of response to trastuzumab. Recently, the roles of ER as a negative and HER2 as a positive indicator for chemotherapy have been established. Ki67 has traditionally been recognized as a poor prognostic factor, but recent studies suggest that measurement of Ki67-positive cells during treatment will more effectively predict treatment efficacy for both anti-hormonal and chemotherapy. p53 mutations are found in 20–35% of human breast cancers and are associated with aggressive disease with poor clinical outcome when the DNA-binding domain is mutated. The utility of cyclin D1 as a predictor of breast cancer prognosis is controversial, but cyclin D1b overexpression is associated with poor prognosis. Likewise, overexpression of the low molecular weight form of cyclin E1 protein predicts poor prognosis. Breast cancers from BRCA1/2 carriers often show high nuclear grades, negativity to ER/PR/HER2, and p53 mutations, and thus, are associated with poor prognosis. The prognostic values of other molecular markers, such as p14^ARF, TBX2/3, VEGF in breast cancer are also discussed. Careful evaluation of these biomarkers with current treatment modality is required to determine whether their measurement or monitoring offer significant clinical benefits.

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

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

Topoisomerase II alpha gene copy loss has adverse prognostic significance in ERBB2-amplified breast cancer: a retrospective study of paraffin-embedded tumor specimens and medical charts

BACKGROUND

Amplification of the ERBB2 (Her-2/neu) oncogene, which occurs in approximately 25% of breast carcinomas, is a known negative prognostic factor. Available data indicate that a variable number of nearby genes on chromosome 17q may be co-amplified or deleted, forming a continuous amplicon of variable size. In approximately 25% of these patients, the amplicon extends to the gene for topoisomerase II alpha (TOP2A), a target for anthracyclines. We sought to understand the significance of these associated genomic changes for breast cancer prognosis and predicting response to therapy.

METHODS AND PATIENTS

Archival tissue samples from 63 breast cancer patients with ERBB2 amplification, stages 0-IV, were previously analyzed with FISH probes for genes located near ERBB2. In the present study, the clinical outcome data were determined for all patients presenting at stages I-III for whom adequate clinical follow up was available.

RESULTS

Four amplicon patterns (Classes) were identified. These were significantly associated with the clinical outcome, specifically, recurrence of breast cancer. The Amplicon class IV with deleted TOP2A had 67% (6/9) cases with recurrence, whereas the other three classes combined had only 12% (3/25) cases (p-value = 0.004) at the time of last follow-up. TOP2A deletion was also significantly associated with time to recurrence (p-value = 0.0002). After adjusting for age in Cox regression analysis, the association between TOP2A deletion and time to recurrence remains strongly significant (p-value = 0.002) whereas the association with survival is marginally significant (p-value = 0.06).

CONCLUSION

TOP2A deletion is associated with poor prognosis in ERBB2-amplified breast carcinomas. Clarification of the mechanism of this association will require additional study.

Cell cycle machinery: links with genesis and treatment of breast cancer

Loss of normal growth control is a hallmark of cancer. Thus, understanding the mechanisms of tissue-specific, normal growth regulation and the changes that occur during tumorigenesis may provide insights of both diagnostic and therapeutic importance. Control of cell proliferation in the normal mammary gland is steroid hormone (estrogen and progestin)-dependent, involves complex interactions with other hormones, growth factors and cytokines and ultimately converges on activation of three proto-oncogenes (c-Myc, cyclin D1 and cyclin E1) that are rate limiting for the G1 to S phase transition during normal cell cycle progression. Mammary epithelial cell-specific overexpression of these genes induces mammary carcinoma in mice, while cyclin D1 null mice have arrested mammary gland development and are resistant to carcinoma induced by the neu/erbB2 and ras oncogenes. Furthermore, c-Myc, cyclins D1, E1 and E2 are commonly overexpressed in primary breast cancer where elevated expression is often associated with a more aggressive disease phenotype and an adverse patient outcome. This may be due in part to overexpression of these genes conferring resistance to endocrine therapies since in vitro studies provide compelling evidence that overexpression of c-Myc and to a lesser extent cyclin D1 and cyclin E1, attenuate the growth inhibitory effects of SERMS, antiestrogens and progestins in breast cancer cells. Thus, abnormal regulation of the expression of cell cycle molecules, involved in the steroidal control of cell proliferation in the mammary gland, are likely to be directly involved in the development, progression and therapeutic responsiveness of breast cancer. Furthermore, a more detailed understanding of these pathways may identify new targets for therapeutic intervention particularly in endocrine-unresponsive and endocrine-resistant disease.

American Society of Clinical Oncology 2007 update of recommendations for the use of tumor markers in breast cancer

PURPOSE

To update the recommendations for the use of tumor marker tests in the prevention, screening, treatment, and surveillance of breast cancer.

METHODS

For the 2007 update, an Update Committee composed of members from the full Panel was formed to complete the review and analysis of data published since 1999. Computerized literature searches of MEDLINE and the Cochrane Collaboration Library were performed. The Update Committee's literature review focused attention on available systematic reviews and meta-analyses of published tumor marker studies. In general, significant health outcomes (overall survival, disease-free survival, quality of life, lesser toxicity, and cost-effectiveness) were used for making recommendations. Recommendations and

CONCLUSIONS

Thirteen categories of breast tumor markers were considered, six of which were new for the guideline. The following categories showed evidence of clinical utility and were recommended for use in practice: CA 15-3, CA 27.29, carcinoembryonic antigen, estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2, urokinase plasminogen activator, plasminogen activator inhibitor 1, and certain multiparameter gene expression assays. Not all applications for these markers were supported, however. The following categories demonstrated insufficient evidence to support routine use in clinical practice: DNA/ploidy by flow cytometry, p53, cathepsin D, cyclin E, proteomics, certain multiparameter assays, detection of bone marrow micrometastases, and circulating tumor cells.

PGDS, A Novel Technique Combining Chromogenic In Situ Hybridization and Immunohistochemistry for the Assessment of ErbB2 (HER2/neu) Status in Breast Cancer

Given the important prognostic and predictive utility of v-erb-b2 erythroblastic leukemia viral oncogene homolog 2 (ErbB2) [human epidermal growth factor receptor-2 (HER2/neu)] in breast cancer, it is recommended that ErbB2 testing be performed on all invasive breast cancers at the time of diagnosis. A consensus, however, has not yet been reached as to the optimal method of evaluating ErbB2 status. Immunohistochemistry to detect protein overexpression and fluorescence in situ hybridization (FISH) to detect ErbB2 gene amplification are the most frequently used methods. As no one detection method fulfills all necessary requirements of reliability, reproducibility, and ease of use, we developed a novel approach in the form of a simple assay we refer to as protein and gene double staining (PGDS) which simultaneously evaluates protein overexpression and gene amplification by combining immunohistochemistry with chromogenic in situ hybridization (CISH). A total of 134 invasive breast carcinomas, including 81 cases with a full-face section and 53 cases included in a tissue microarray (TMA), were assessed by PGDS, and the results were correlated with ErbB2 gene amplification status as determined by FISH. ErbB2 gene copy number determined by CISH analysis in the PGDS assay showed excellent concordance with that of FISH (correlation coefficient 0.82; P<0.001 with full-face section cases, and 0.98; P<0.001 with cases in a TMA). The overall concordance rate for gene amplification status between PGDS and FISH was 90.12% in cases with a full-face section and 92.45% with TMA cases. Perfect correlation was seen between the PGDS assay and FISH in cases that were considered either nonamplified or highly amplified by the dual assay. Of the 17 cases that showed low amplification by PGDS, 5 were classified as nonamplified by FISH. Correction for chromosome 17 copy number in the FISH assessment contributed to the discordance between CISH and FISH results. This newly developed PGDS method represents a novel approach to ErbB2 status determination that combines the assessment of both protein overexpression and gene amplification in one simple assay. It is likely that this assay will aid in immunohistochemical calibration and will also increase the sensitivity and specificity of ErbB2 testing.

Efficacy of lower dose capecitabine in patients with metastatic breast cancer and factors influencing therapeutic response and outcome

OBJECTIVE

Capecitabine exerts considerable therapeutic efficacy in metastatic breast cancer (MBC) patients previously treated with anthracyclines and taxanes.

MATERIALS AND METHODS

In this study, the efficacy and safety of lower dose capecitabine (2000 mg/m(2)/d) in patients with anthracycline- and taxane-pretreated MBC were studied with a special emphasis on the potential predictors of time to tumor progression (TTP) and response to the capecitabine treatment.

RESULTS

The overall response rate (ORR) was 17%. The median TTP was 5 months. Among various factors analyzed, univariate analysis showed that a performance status (PS) of 2 and the presence of visceral metastases were inversely correlated with TTP. Multivariate analysis showed that a poor PS score was associated with impaired TTP.

CONCLUSIONS

Our study indicates that lower dose capecitabine has substantial antitumor activity and a favorable safety profile in the treatment of anthracycline- and taxane-pretreated MBC. Also, only performance score was demonstrated to be a significant parameter affecting TTP.

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

A positive role for PEA3 in HER2-mediated breast tumour progression

Overexpression of HER2 is associated with an adverse prognosis in breast cancer. Despite this, the mechanism of its transcriptional regulation remains poorly understood. PEA3, a MAP kinase (MAPK)-activated member of the Ets transcription factor family has been implicated in the transcriptional regulation of HER2. The direction of its modulation remains controversial. We assessed relative levels of PEA3 expression and DNA binding in primary breast cultures derived from patient tumours (n=18) in the presence of an activated MAPK pathway using Western blotting and shift analysis. Expression of PEA3 in breast tumours from patients of known HER2 status (n=107) was examined by immunohistochemistry. In primary breast cancer cell cultures, growth factors induced interaction between PEA3 and its DNA response element. Upregulation of PEA3 expression in the presence of growth factors associated with HER2 positivity and axillary lymph node metastasis (P=0.034 and 0.049, respectively). PEA3 expression in breast cancer tissue associated with reduced disease-free survival (P<0.001), Grade III tumours (P<0.0001) and axillary lymph node metastasis (P=0.026). Co-expression of PEA3 and HER2 significantly associated with rate of recurrence compared to patients who expressed HER2 alone (P=0.0039). These data support a positive role for PEA3 in HER2-mediated oncogenesis in breast cancer.

Targeting oncogenes to improve breast cancer chemotherapy

Despite recent advances in treatment, breast cancer remains a serious health threat for women. Traditional chemotherapies are limited by a lack of specificity for tumor cells and the cell cycle dependence of many chemotherapeutic agents. Here we report a novel strategy to help overcome these limitations. Using triplex-forming oligonucleotides (TFOs) to direct DNA damage site-specifically to oncogenes overexpressed in human breast cancer cells, we show that the effectiveness of the anticancer nucleoside analogue gemcitabine can be improved significantly. TFOs targeted to the promoter region of c-myc directly inhibited gene expression by approximately 40%. When used in combination, specific TFOs increased the incorporation of gemcitabine at the targeted site approximately 4-fold, presumably due to induction of replication-independent DNA synthesis. Cells treated with TFOs and gemcitabine in combination showed a reduction in both cell survival and capacity for anchorage-independent growth (approximately 19% of untreated cells). This combination affected the tumorigenic potential of these cancer cells to a significantly greater extent than either treatment alone. This novel strategy may be used to increase the range of effectiveness of antitumor nucleosides in any tumor which overexpresses a targetable oncogene. Multifaceted chemotherapeutic approaches such as this, coupled with triplex-directed gene targeting, may lead to more than incremental improvements in nonsurgical treatment of breast tumors.

Benefit from adjuvant tamoxifen therapy in primary breast cancer patients according oestrogen receptor, progesterone receptor, EGF receptor and HER2 status

BACKGROUND

Most women with oestrogen receptor (ER) positive primary breast cancer receive adjuvant tamoxifen after surgery. The measurement of tumour biomarkers should allow better selection of patients for such treatment or for therapies such as aromatase inhibitors.

PATIENTS AND METHODS

Histopathological blocks of primary breast cancer patients who had been randomized to receive 2-years tamoxifen or no adjuvant therapy in two mature randomised clinical trials were retrieved. Immunohistochemical staining for ER, progesterone receptor (PgR), HER2 and epidermal growth factor receptor (EGFR) was undertaken. The primary endpoint was relapse free survival.

RESULTS

813 patients were included in the study. Benefit from tamoxifen was seen in ER-positive patients [Relative risk (rr) 0.77, ci 0.63-0.93]. ER-negative patients also showed a strong trend to benefit from tamoxifen (rr 0.73, ci 0.52-1.02) which was largely confined to the PgR-positive group. Amongst the ER-positive group, PgR-positive and PgR-negative patients showed similar benefit (rr 0.81; ci 0.65-1.02 and 0.70; ci 0.49-0.99, respectively). Patients positive for HER2 did not benefit significantly (rr 1.14; ci 0.75-1.73) but this group was small.

CONCLUSIONS

Measurement of PgR status in ER-negative patients defines a group of patients that benefit from tamoxifen but would be excluded from tamoxifen therapy on the basis of ER status alone. The data are consistent with HER2 positive tumours being resistant to tamoxifen.

Co-expression of steroid hormone receptors (estrogen receptor alpha and/or progesterone receptors) and Her2/neu (c-erbB-2) in breast cancer: clinical outcome following tamoxifen-based adjuvant therapy

In breast cancer patients, the expression of steroid hormone receptors (HR:ERalpha/PR) appears inversely correlated with Her2/neu (not all reports agree on this negative correlation). Moreover, some but not all studies suggest that HR+/Her2/neu+ patients have a poor response to endocrine therapy, making this special group a matter of debate. In this prospective study we have analyzed the clinical outcome of our HR+/Her2/neu+ patients (n=51) selected from 516 consecutive stages I-II cases, with a follow-up 5-10 years (mean 7.3), treated with standard adjuvant therapy with tamoxifen (TAM) (TAM alone or TAM after chemotherapy). This group was compared with the HR+/Her-2/neu- patients (n=129) treated also with TAM. The tumor biopsies were studied by immunohistochemistry. We found that the association HR+/Her2/neu- was 2.5 times higher than the association HR+/Her2/neu+ (25% versus 9.9%, respectively). Our study also showed that the disease free survival (DFS) of the patients co-expressing HR and Her2/neu was significantly lower than those expressing HR but lacking of Her2/neu (p<0.001). A similar result was obtained when the overall survival (OS) was evaluated (p=0.001). All of these patients received hormone therapy with TAM, alone or after chemotherapy. When the analysis was performed in the patients treated with TAM alone, again the expression of Her-2/neu had a negative impact on both the DFS and the OS (p<0.05).

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

PURPOSE

Resistance to tamoxifen is linked to overexpression of HER2, and aromatase inhibitors show particular benefit in progesterone receptor (PR)-negative patients. We previously reported reduced survival in patients overexpressing HER1, HER2, and HER3. We now show that both HER1-3 and PR status predicts for early relapse in estrogen receptor (ER)-positive tamoxifen-treated breast cancer patients.

EXPERIMENTAL DESIGN

Tissue microarray technology was used to analyze 402 ER-positive tamoxifen-treated patients. Immunohistochemistry using epidermal growth factor receptor, HER2, HER3, HER4, and PR antibodies was done. Kaplan-Meier life table and Cox Regression analysis (log-rank testing of differences in breast cancer-related relapse on tamoxifen) was done.

RESULTS

HER1-3 (but not HER4) overexpression predicted for early relapse on tamoxifen (P = 0.0060). PR-negative cases were also significantly more likely to relapse while on tamoxifen (P= 0.017). HER1-3-positive and/or PR-negative patients combined as a "high-risk" group were significantly more likely to relapse on tamoxifen in univariate (P < 0.0001) and Cox's multivariate analysis (P = 0.0069). However, this applied to early relapse on tamoxifen only, as any disease relapse after 3 years of tamoxifen was unrelated to PR/HER status.

CONCLUSIONS

We show that HER1-3 and PR status can identify time-dependent de novo tamoxifen resistance with risk declining markedly after 3 years of tamoxifen treatment. These results parallel data from the ATAC and Intergroup Exemastane Study trials which suggest that whereas PR-negative patients derive greater benefit from initial aromatase inhibitor treatment, PR status has no effect on response when given as delayed treatment to those disease free on tamoxifen after 3 years.

A meta-analysis on the interaction between HER-2 expression and response to endocrine treatment in advanced breast cancer

PURPOSE

Experimental data suggest a complex cross-talk between HER-2 and estrogen receptor, and it has been hypothesized that HER-2-positive tumors may be less responsive to certain endocrine treatments. Clinical data, however, have been conflicting. We have conducted a meta-analysis on the interaction between the response to endocrine treatment and the overexpression of HER-2 in metastatic breast cancer.

EXPERIMENTAL DESIGN

Studies have been identified by searching the Medline, Embase, and American Society of Clinical Oncology abstract databases. Selection criteria were (a) metastatic breast cancer, (b) endocrine therapy (any line of treatment), and (c) evaluation of HER-2 expression (any method). For each study, the relative risk for treatment failure for HER-2-positive over HER-2-negative patients with 95% confidence interval was calculated as an estimate of the predictive effect of HER-2. Pooled estimates of the relative risk were computed by the Mantel-Haenszel method.

RESULTS

Twelve studies (n = 2,379 patients) were included in the meta-analysis. The overall relative risk was 1.42 (95% confidence interval, 1.32-1.52; P < 0.00001; test for heterogeneity = 0.380). For studies involving tamoxifen, the pooled relative risk was 1.33 (95% confidence interval, 1.20-1.48; P < 0.00001; test for heterogeneity = 0.97); for studies involving other hormonal drugs, a pooled relative risk of 1.49 (95% confidence interval, 1.36-1.64; P < 0.00001; test for heterogeneity = 0.08) was estimated. A second meta-analysis limited to tumors that were either estrogen receptor positive, estrogen receptor unknown, or estrogen receptor negative/progesterone receptor positive yielded comparable results.

CONCLUSIONS

HER-2-positive metastatic breast cancer is less responsive to any type of endocrine treatment. This effect holds in the subgroup of patients with positive or unknown steroid receptors.

Adverse effect of adjuvant tamoxifen in premenopausal breast cancer with cyclin D1 gene amplification

Cyclins D1 and A2 are cell cycle regulators that also have the ability to interact with the estrogen receptor (ER) and consequently interfere with antiestrogen treatment in breast cancer. Experimental data support this concept, but the clinical relevance needs to be further established. In this study, we evaluated cyclin D1 and A2 protein expression by immunohistochemistry and cyclin D1 gene (CCND1) amplification by fluorescence in situ hybridization in 500 primary breast cancers arranged in tissue microarrays. Patients had been randomized to 2 years of adjuvant tamoxifen or no treatment with a median follow-up of 14 years, allowing for subgroup analysis of treatment response defined by cyclin status. We found that both cyclin D1 and A2 protein overexpression was associated with an impaired tamoxifen response, although not significant in multivariate interaction analyses, whereas tamoxifen-treated patients with CCND1-amplified tumors had a substantially increased risk for disease recurrence after tamoxifen treatment in univariate analyses [relative risk (RR), 2.22; 95% confidence interval (95% CI), 0.94-5.26; P = 0.06] in contrast to non-amplified tumors (RR, 0.39; 95% CI, 0.23-0.65; P < 0.0001). Consequently, a highly significant interaction between tamoxifen treatment and CCND1 amplification could be shown regarding both recurrence-free survival (RR, 6.38; 95% CI, 2.29-17.78; P < 0.001) and overall survival (RR, 5.34; 95% CI, 1.84-15.51; P = 0.002), suggesting an agonistic effect of tamoxifen in ER-positive tumors. In node-positive patients, the disparate outcome according to gene amplification status was even more accentuated. In summary, our data implicate that despite a significant correlation to cyclin D1 protein expression, amplification status of the CCND1 gene seems a strong independent predictor of tamoxifen response, and possibly agonism, in premenopausal breast cancer.

Reliability of chromogenic in situ hybridization for detecting HER-2 gene status in breast cancer: comparison with fluorescence in situ hybridization and assessment of interobserver reproducibility

Accurate determination of HER-2 status is important in the management of patients with breast cancer, especially in determining their eligibility for trastuzumab therapy. Fluorescence in situ hybridization (FISH) has been regarded as the gold standard method for detecting HER-2 gene amplification. Recently, chromogenic in situ hybridization (CISH), in which HER-2 is detected by a peroxidase reaction and the gene copies are determined by regular bright-field microscopy, has emerged as a potential alternative to FISH. However, this method requires validation before it can be adopted into clinical practice. In this study, we evaluated 80 cases of invasive breast carcinoma by CISH, compared the results with those obtained by FISH, and assessed interobserver reproducibility among three observers. We found that agreement among the three pathologists on the CISH-determined HER-2 status was achieved in 73 cases (91%), all of which had results matching the corresponding FISH results: 54 nonamplified and 19 amplified. Of the 19 amplified cases, 13 were scored unanimously as high-level amplification; six had a minor scoring discrepancy (ie, low-level vs high-level amplification). A major scoring discrepancy (ie, nonamplification vs amplification) was found in the remaining seven cases, three of which were amplified and four of which were nonamplified by FISH. Two of the latter cases had a polysomy of chromosome 17. The cases that caused scoring difficulty were those with an equivocal or borderline signal number against a high background. Overall, there was nearly perfect agreement between the CISH and corresponding FISH results, and interpretation of CISH results were highly reproducible among the three pathologists. We conclude that, in general, HER-2 status can be reliably assessed by CISH. Confirmatory FISH is recommended in cases with equivocal or borderline CISH copy numbers.

The clinical significance of axillary lymph node micrometastases in breast cancer

OBJECTIVE

To evaluate the clinical significancer of axillary lymph-node micrometastases, in the era of sentinel lymph node (SLN) biopsy.

DATA SOURCES

Searches of MEDLINE (1966-2003) and an extensive manual review of journals were performed using the key search terms breast cancer, axillary lymph-node micrometastases, micrometastatic disease, and SLN biopsy.

STUDY SELECTION

All articles identified from the data sources were evaluated and all information deemed relevant was included for this review.

CONCLUSIONS

Axillary lymph-node micrometastases can be detected by serial sectioning, immunohistochemistry, or reverse transcriptase-polymerase chain reaction (RT-PCR). The presence of axillary SLN micrometastases is generally associated with a worse prognosis and is an indication for axillary lymph node dissection (ALND) and adjuvant therapy. The clinical significance of micrometastases identified by RT-PCR remains unknown and further research with longer follow-up is needed to ascertain the clinical implications of a positive result.

HER-2 amplification, HER-1 expression, and tamoxifen response in estrogen receptor-positive metastatic breast cancer: a southwest oncology group study

PURPOSE

Preclinical data indicate that expression of the ErbB family of receptors, such as HER-2 and HER-1 (EGFR) may be involved in endocrine resistance. Evidence of resistance from clinical studies has been inconsistent. The present study examined whether HER-2 gene amplification or HER-1 expression predicted response to tamoxifen.

PATIENTS AND METHODS

Three hundred and forty nine patients had estrogen receptor (ER)-positive breast cancer and received daily tamoxifen as initial therapy for advanced disease. HER-2 gene amplification, detected by fluorescence in situ hybridization, and HER-1 expression, evaluated by immunohistochemistry, was determined on 136 and 204 patients, respectively.

RESULTS

HER-2 amplification was correlated with lower ER (P = 0.02), HER-1 positivity (P = 0.004), and HER-2 protein overexpression (P < 0.00001). The response rate was 56% for HER-2 non-amplified versus 47% for HER-2 amplified tumors (P = 0.38), and 58% for HER-1-negative versus 36% for HER-1-positive (P = 0.05). Time to treatment failure (TTF) was 7 months for non-amplified HER-2 tumors and 5 months (P = 0.007) for amplified HER-2 tumors, and there was a trend toward a better overall survival (OS) in patients with non-amplified HER-2 tumors (median 31 versus 25 months, respectively, P = 0.07). For positive versus negative HER-1 tumors, TTF was 4 versus 8 months (P = 0.08) and median survival was 24 versus 31 months (P = 0.41). Combining HER-1 expression and HER-2 gene status, patients with both negative HER-1 expression and non-amplified HER-2 had longer TTF (P = 0.001) and OS (P = 0.03) than if either were positive. In multivariate analysis, HER-2 was not an independent factor for TTF and OS, although HER-1 was significant for TTF only (P </= 0.001).

CONCLUSION

Patients with HER-2 amplification and HER-1 expression had lower ER levels and were modestly less responsive to tamoxifen, suggesting that molecular events in addition to those involving the ErbB receptors are important in determining the endocrine-resistant phenotype.

Her2/neu expression predicts the response to antiaromatase neoadjuvant therapy in primary breast cancer: subgroup analysis from celecoxib antiaromatase neoadjuvant trial

PURPOSE

Many studies suggest that Her2/neu play an important role in neoadjuvant endocrine therapy. This study aimed to determine whether the level of Her2/neu expression in advanced breast cancer changes after antiaromatase neoadjuvant treatment, as well as to identify the relationship between Her2/neu expression and response to this kind of therapy.

EXPERIMENTAL DESIGN

Thirty-six postmenopausal patients with hormonal receptor-positive primary breast cancer were included in a study of three monthly cycles of neoadjuvant endocrine therapy with either Aromasin (25 mg daily) or Femara (2.5 mg daily). Immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) for Her2/neu were conducted both on pretreatment biopsies and surgical tumors.

RESULTS

Using IHC, 5 of 36 (13.9%) of the patients had a Her2/neu overexpression after treatment, as compared with 16 of 36 (44.4%) before. Meanwhile, there was no change in 21 (58.3%) patients, and through FISH, there was a change from amplification to no amplification in 15 (41.7%) patients. The response rate to the treatment was 75% for Her2/neu (+) tumors and 35% for Her2/neu (-) tumors (P = 0.017) while FISH was performed. The response rate was also significantly affected by the decrease in Her2/neu status after the treatment, with 73% of the tumors showing decreased Her2/neu expression and with 38% of the tumors showing no change of Her2/neu expression (P = 0.037).

CONCLUSIONS

Using both IHC and FISH, advanced breast cancers show statistical evidence of decreasing incidence of Her2/neu expression after antiaromatase neoadjuvant treatment. Our data also suggest that Her2/neu expression and its change during the treatment might be predictive markers for this kind of therapy.

Comparison ofHER-2 status determined by fluorescence in situ hybridization in primary and metastatic breast carcinoma

BACKGROUND

Accurate assessment of HER-2 status is necessary prior to anti-HER-2 antibody (trastuzumab) therapy for metastatic breast carcinoma. However, controversy exists regarding whether to assess HER-2 status in the primary tumor or in metastatic lesions. It is also unclear whether HER-2 status can change during disease progression or after chemotherapy.

METHODS

Breast carcinoma samples from 60 women with known HER-2 status in both primary tumors and paired metastases (locoregional disease, n = 43 patients; distant disease, n = 17 patients) were reviewed retrospectively. Thirty-two patients underwent chemotherapy before their metastatic lesions were sampled, including 18 patients who received neoadjuvant chemotherapy and 14 patients who received adjuvant chemotherapy. The HER-2 gene was examined by fluorescence in situ hybridization either in paraffin-embedded tissue samples (48 primary tumors and 9 metastatic tumors) or in fine-needle aspirates (12 primary tumors and 51 metastatic tumors). HER-2 gene amplification was defined as a HER-2:chromosome 17 signal ratio >/= 2.0.

RESULTS

The HER-2 status of primary and metastatic tumors agreed in 58 of 60 patients (97%), including 18 (30%) amplified tumors and 40 (67%) nonamplified tumors. A discrepancy in HER-2 status was observed in specimens from two patients in which HER-2 amplification was detected in the primary tumor but not the metastatic tumors. In one patient, three foci of tumor nodules were found in the same breast; the HER-2 status was assessed in only one of them, which showed amplification; however, HER-2 amplification was not detected in the axillary lymph node metastasis. In another patient, the HER-2 gene was amplified in the primary tumor but not in the liver metastasis. No metastases showed HER-2 amplification without amplification in the primary tumor. Locoregional and distant metastases demonstrated similar concordance rates with their corresponding primary tumors (98% and 94%, respectively). Complete concordance of HER-2 status was found between primary tumors prior to chemotherapy and metastases that were sampled after chemotherapy.

CONCLUSIONS

The HER-2 status in breast carcinoma generally was stable during metastasis, whether to locoregional or distant sites. Chemotherapy did not modify the HER-2 status in metastatic lesions. Therefore, HER-2 amplification can be evaluated reliably in material from either primary or metastatic tumors in most patients. Further study with larger series is warranted to elucidate the significance of discordant results.

Evidence-based medicine, medical decision analysis, and pathology

Recent advances in molecular pathology and other technologies such as proteomics present pathologists with the challenge of integrating the new information generated with high-throughput methods with current diagnostic models based mostly on histopathology and clinicopathologic correlations. Parallel developments in the field of medical informatics and bioinformatics provide the technical and mathematical methods to approach these problems in a rational manner. However, it remains unclear whether pathologists or other medical specialists will become primarily responsible for the development and maintenance of these multivariate and multidisciplinary diagnostic and prognostic models that are hoped to provide more accurate, individualized patient-based information. Evidence-based medicine (EBM) and medical decision analysis (MDA) are relatively new disciplines that use quantitative methods to assess the value of information, differentiate fact from myth, and integrate so-called best evidence into multivariate models for the assessment of prognosis, response to therapy, selection of laboratory tests, and other complex problems that influence individual patient care. We review from an epistemological viewpoint the current approach to information in pathology and describe some of the concepts developed by the practitioners of EBM and MDA.

HER2 overexpression as a prognostic factor in metastatic breast cancer patients treated with high-dose chemotherapy and autologous stem cell support

We retrospectively evaluated the predictive and prognostic role of HER2 expression in 44 metastatic breast cancer (MBC) patients treated with high-dose consolidation chemotherapy (HDCT) and autologous stem cell support after induction chemotherapy (IC) with six courses of epirubicin+paclitaxel (22 patients) or gemcitabine+epirubicin+paclitaxel (22 patients). HER2 expression was evaluated by an immunohistochemical method (Herceptest, Dako). A total of 13 patients (29.5%) showed a HER2 overexpression (score 3+). After IC, nine patients were in complete response (CR), 30 in partial response (PR), and five in stable disease (SD); after HDCT, 20 (45.5%) obtained a CR, and 23 were in PR, for a conversion rate of 48.5%. Conversion rate for HER2-positive patients was 87.5 vs 37% for HER2-negative patients (P=0.018). The median progression-free (PFS) and overall survivals (OS) were 17.6 (95% CI 13.2-22.0) and 44 (95% CI 25.9-62.3) months, respectively. Patients with HER2 overexpression experienced a significantly (P=0.0042) shorter median PFS (15.3 months, 95% CI 11.1-19.5) compared to HER2-negative patients (21.3 months, 95% CI 14.3-28.4). The median OS was 27.6 months (95% CI 4.5-50.7) in HER2-positive patients and 50.3 months (95% CI 38.7-62.0) in HER2-negative patients (P=0.345). These results indicate that HER2 overexpression predicts a worse outcome for patients with MBC treated with HDCT, despite the high CR rate obtained in this subset of patients.

The role of Tbx2 and Tbx3 in mammary development and tumorigenesis

TBX2 and TBX3 are members of a family of genes encoding developmental transcription factors, characterized by a 200 amino acid DNA binding domain (T-box). Tbx2 and Tbx3 are closely related T-box proteins that have been implicated in development of a number of different tissues including the mammary gland. TBX3 is required for normal mammary development in mouse models and in patients with ulnar-mammary syndrome (UMS). In addition to a role in development, TBX2 and TBX3 have been implicated in tumor development through downregulation of the alternative reading frame (ARF) tumor suppressor and an associated bypass of senescence. Here we review the current information on the roles of Tbx2 and Tbx3 in mammary gland development and tumorigenesis.

Breast cancer biomarkers and molecular medicine

The first part of this two-part review of established and emerging breast cancer biomarkers and molecular diagnostics considers breast cancer predisposition, screening tests for diagnosis, diagnosis using small specimens and metastatic lesions, micrometastatic disease and breast cancer prognosis assessment. Prognostic factors covered in this review include: cytogenetic markers, DNA ploidy and S phase determination, cell proliferation markers, cell cycle regulators and growth factor measurements including epithelial growth factor receptor, HER-2/neu and a variety of other relevant molecules controlling proliferation, differentiation and angiogenesis. The first section of part two will continue the consideration of breast cancer prognostic factors including oncogenes, tumor suppressor genes, cell adhesion molecules, invasion-associated proteins and proteases, hormone receptor proteins, drug resistance proteins, apoptosis regulators, transcription factors, telomerase, DNA repair and methylation and transcriptional profiling using high-density genomic microarrays. The second section of part two will consider the prediction of therapy response using the techniques of pharmacogenetics and pharmacogenomics.

Targeted therapy in breast cancer: the HER-2/neu gene and protein

The HER-2/neu oncogene, a member of the epidermal growth factor receptor or erb gene family, encodes a transmembrane tyrosine kinase receptor that has been linked to prognosis and response to therapy with the anti-HER-2-humanized monoclonal antibody, trastuzumab (Herceptin, Genentech, South San Francisco, CA) in patients with advanced metastatic breast cancer. HER-2/neu status has also been tested for its ability to predict the response of breast cancer to other therapies including hormonal therapies, topoisomerase inhibitors, and anthracyclines. This review includes an analysis of 80 published studies encompassing more than 25,000 patients designed to consider the relative advantages and disadvantages of the various methods of measuring HER-2/neu in clinical breast cancer specimens. Southern blotting, PCR amplification detection, and fluorescence in situ hybridization assays designed to detect HER-2/neu gene amplification are compared with HER-2/neu protein overexpression assays performed by immunohistochemical techniques applied to frozen and paraffin-embedded tissues and enzyme immunoassays performed on tumor cytosols. The significance of HER-2/neu overexpression in ductal carcinoma in situ and the HER-2/neu status in uncommon female breast conditions and male breast cancer are also considered. The role of HER-2/neu testing for the prediction of response to trastuzumab therapy in breast cancer is reviewed along with the current studies designed to test whether HER-2/neu status can predict the response to standard and newer hormonal therapies, cytotoxic chemotherapy, and radiation. The review will also evaluate the status of serum-based testing for circulating HER-2/neu receptor protein and its ability to predict disease outcome and therapy response.