Evaluation of Clinical Outcomes According to HER2 Detection by Fluorescence In Situ Hybridization in Women with Metastatic Breast Cancer Treated with Trastuzumab

Hybridization for human epidermal growth factor receptor 2 testing in gastric carcinoma: a comparison of fluorescence in-situ hybridization with a novel fully automated dual-colour silver in-situ hybridization method

Aims:

Amplification of the human epidermal growth factor receptor 2 (HER2) gene has been reported in gastric carcinoma (GC). Accordingly, trastuzumab plus chemotherapy has recently become the new standard treatment for HER2-positive advanced GCs. The aim was to compare the alleged gold standard for hybridization [fluorescence in-situ hybridization (FISH)] with a novel, fully automated brightfield dual-colour silver-enhanced in-situ hybridization (SISH) method.

Methods and results:

The studies series was comprised of 166 GC samples. Additionally, tumours with discordant results obtained by FISH and SISH were analysed by real-time quantitative polymerase chain reaction (PCR) with the LightMix kit HER-2/neu. Of the samples, 17.5% and 21% were amplified by FISH and SISH, respectively. Heterogeneity was identified in up to 52% of cases. In 96.4% of cases, FISH showed the same results as SISH. All six discordant cases were positive by SISH and negative by FISH. On review of the FISH slides, all contradictory cases were polysomic and were confirmed to be negative for amplification by real-time PCR. Interestingly, all ratios in this latter group were between 2.06 and 2.50, so setting the cut-off for amplification at ≥3 resulted in perfect concordance.

Conclusions:

Dual-colour SISH represents a novel method for the determination of HER2 status in GC.

Predictive and prognostic molecular markers for cancer medicine

Over the last 10 years there has been an explosion of information about the molecular biology of cancer. A challenge in oncology is to translate this information into advances in patient care. While there are well-formed routes for translating new molecular information into drug therapy, the routes for translating new information into sensitive and specific diagnostic, prognostic and predictive tests are still being developed. Similarly, the science of using tumor molecular profiles to select clinical trial participants or to optimize therapy for individual patients is still in its infancy. This review will summarize the current technologies for predicting treatment response and prognosis in cancer medicine, and outline what the future may hold. It will also highlight the potential importance of methods that can integrate molecular, histopathological and clinical information into a synergistic understanding of tumor progression. While these possibilities are without doubt exciting, significant challenges remain if we are to implement them with a strong evidence base in a widely available and cost-effective manner.

Clinical and health economic outcomes of alternative HER2 test strategies for guiding adjuvant trastuzumab therapy

AIM

To evaluate the clinical outcomes and cost-effectiveness of human epidermal growth factor receptor 2 (HER2) testing strategies to guide adjuvant trastuzumab (AT) therapy in women with HER2-positive breast cancer.

METHODS

A literature review produced 72 studies comparing HER2 test methods, and we computed concordance (assuming fluorescence in situ hybridization [FISH] as a reference assay) to assess performance relative to American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guidelines. An economic analysis provided cost-effectiveness of alternative strategies, including a Monte Carlo simulation to vary key assumptions such as test price and performance.

RESULTS

Of 46 studies comparing immunohistochemistry (IHC) and FISH, only seven met the ASCO/CAP guideline of 95% or better concordance. A total of 14 out of 21 studies comparing chromogenic in situ hybridization and three out of five studies comparing silver-enhanced in situ hybridization met the guideline. Confirmation of IHC 2+ and 3+ and primary FISH strategies are likely to reduce costs and improve quality of life relative to confirmation of IHC 2+ only. Initial testing with a gene amplification-based assay is probably a cost-effective alternative to confirmation of IHC 2+ and 3+. The results are not sensitive to varying test price but are sensitive to test accuracy below 98%.

CONCLUSION

Using a primary gene amplification-based assay to guide AT therapy for HER2-positive breast cancer probably results in lower US medical costs, increased life-years and increased quality of life compared with confirmation of IHC 2+ with a gene amplification-based assay. We recommend the ASCO/CAP guidelines reflect 98% or greater concordance relative to a reference assay. Additional research regarding therapy response is required to further differentiate between gene amplification-based assays.

The human epidermal growth factor receptor 2 (HER2)

The declared "war on cancer" aimed to eradicate this disease using our knowledge of cancer cell biology to develop novel therapeutics. One such target of these novel therapies has been the human epidermal growth factor receptor 2 (HER2) gene. Unique in the approach to abolishing function of this gene coded receptor, it was the first target of new monoclonal antibody therapy targeting the extracellular receptor and now also a target of small molecule drugs against the intracellular tyrosine kinase domain. In this instance, it was also one of the first applications of personalized medicine requiring companion diagnostics. In this manuscript, we review the biology and clinical applications of HER2 as a biomarker of disease and as a therapeutic target.

Blockade of the HER family of receptors in the treatment of HER2-positive metastatic breast cancer

Breast cancer is the most common type of cancer among women and the second leading cause of cancer death in the United States. Metastatic breast cancer is considered incurable, and treatment is aimed at palliating symptoms, achieving remission, and prolonging survival. Treatment options for metastatic disease vary based on tumor surface markers and clinical factors in an individual patient and include cytotoxic chemotherapy, hormonal therapy, biological therapy, or some combination of these. An important molecular determinant of therapy is the human epidermal growth factor receptor 2 (HER2) positivity of the tumor, which affects response to HER2-targeted treatment. HER2 is a member of the human epidermal growth factor receptor family of receptor tyrosine kinases, also known as the HER family, which activates signaling that promotes tumorigenic cellular processes such as proliferation and evasion of apoptosis. Several targeted agents, including monoclonal antibodies and tyrosine kinase inhibitors that inhibit one or more HER family receptors have been developed that affect signaling through this pathway. Some of these, such as trastuzumab and lapatinib, have been approved for breast cancer treatment. Resistance to therapy is a challenge that limits the duration of benefit achieved with these agents. Therefore, combinations of HER family-targeted agents with other therapies such as cytotoxic agents, hormonal therapy, or inhibitors of other cellular pathways, are being developed to exploit synergy and overcome resistance mechanisms. Here we review the HER family-targeted agents currently approved or in development for HER2-positive metastatic breast cancer with a focus on strategies to overcome tumor resistance.

Evidence for PTEN-independent Akt activation and Akt-independent p27(Kip1) expression in advanced bladder cancer

In the treatment of advanced bladder cancer (BC), attention has recently focused on small molecule therapy concerning EGFR and the downstream Akt signalling pathway. Cellular deregulation processes are poorly understood, and biological determinants for the selection of therapy and monitoring are currently not available. The proteins PTEN, p-Akt and p27(Kip1) are suggested to be potentially significant biomarkers of Akt signalling. In this study, we investigated the expression of these proteins in advanced BC. PTEN, p-Akt and p27(Kip1) expression was determined immunohistochemically in 86 T2-4 BC specimens using a tissue microarray technique. Staining was documented with regard to intensity, cellular frequency and a multiplied staining score. Staining characteristics of the three proteins were correlated by regression analysis with the parameters of tumour stage and grade. A positive correlation was observed in the expression scores of PTEN and p-Akt, p-Akt and p27(Kip1) as well as PTEN and p27(Kip1) (p<0.02 for all combinations). The positive correlation between PTEN and p-Akt resulted mainly due to the strong correlation of PTEN intensity with p-Akt (p=0.0003 and p=0.0006 to p-Akt frequency and intensity, respectively). A positive correlation between p-Akt and p27(Kip1) was noted for p-Akt frequency as well as intensity (p<0.05 for all combinations). The positive correlation between PTEN and p27(Kip1) resulted due to the correlation of PTEN intensity alone with p27(Kip1) (p<0.03 for p27(Kip1) frequency and intensity), whereas no significance was noted for PTEN frequency. No correlation was found between T or G and expression of the proteins. However, activation of Akt in BC is known to occur independently of PTEN protein loss and appears not to cause a decrease of p27(Kip1). However, a direct regulatory impact of PTEN on p27(Kip1) was found. PTEN intensity, rather than frequency, appears to be a superior biomarker. These results may provide information to support research into protein profiling-predicted targeted therapy for BC. Correlations to benign urothelium, superficial BC specimens and follow-up data remain to be investigated.

HER2 gene amplification occurs frequently in the micropapillary variant of urothelial carcinoma: analysis by dual-color in situ hybridization

Human epidermal growth factor receptor-2 (HER2) is a well-recognized growth-promoting factor in cancer, although its application to urothelial carcinoma has been limited because of a low frequency of gene amplification. We evaluated HER2 protein expression and gene amplification in micropapillary carcinoma, a rare but highly aggressive variant of urothelial carcinoma by dual-color in situ hybridization. Gene amplification was defined by a HER2:CHR17 ratio of ≥2.2; low and high levels of amplification were further defined as <2.5 and ≥2.5, respectively. Immunohistochemistry was used to determine HER2 protein expression using the American Society of Clinical Oncology/College of American Pathologists Guidelines of HER2 staining. Protein expression, gene amplification, and chromosome 17 aneusomy were compared by Jonchkeere-Terpstra and Cochran-Armitage trend tests. In all, 19 of the 20 micropapillary carcinoma samples yielded usable dual-color in situ hybridization and immunohistochemistry results for evaluation. Overall, 68% (n=13) demonstrated HER2 protein expression of 2+ to 3+ staining. Gene amplification was present in 42% of samples (n=8), with 100% correlation with 2+ and 3+ protein expression. Gene amplification and protein expression were significantly associated (P=0.01). Overall, 53% of samples (n=10) had aneusomy of chromosome 17. Chromosome 17 aneusomy was present in approximately half of the samples evaluated, suggesting inherent genomic instability in this variant of urothelial carcinoma. However, increased HER2:CHR17 ratios demonstrate increased HER2 expression due to amplification in the majority of micropapillary carcinomas. These results suggest that HER2-targeted therapy may be successful on the genomic level in patients with this disease.

Breast cancers presenting luminal B subtype features show higher discordant human epidermal growth factor receptor 2 results between immunohistochemistry and fluorescence in situ hybridization

BACKGROUND

The aims of this study were to compare human epidermal growth factor receptor 2 (HER2) results between immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH), and to investigate the clinicopathological characteristics and outcomes according to their results.

METHODS

Using consecutive tissue microarrays, IHC and FISH were performed as guidelines in 950 invasive breast cancers treated between November 1999 and August 2005. Characteristics and outcomes were retrospectively analyzed using a chi-square test, the Kaplan-Meier method, and Cox's model.

RESULTS

FISH-positivity was observed in 2.6%, 4.8%, 28.1%, and 93.8% of IHC 0, 1+, 2+, and 3+, respectively, and the concordance rate between the 2 assays was 95.5%. IHC-positive or FISH-positive cases were associated with poorer differentiation, negative expression of hormone receptors, and higher proliferative index. Among IHC-equivocal or IHC-negative patients, positive FISH was negatively associated with survival in univariate and multivariate analyses. Among IHC-negative patients, tumors showing luminal B subtype features such as estrogen receptor (ER)-positive, grade II/III, and high Ki-67 presented discordantly high FISH-positivity. Among IHC-positive cases, FISH was not related to outcomes.

CONCLUSIONS

The result of FISH is significantly related to prognosis of patients with IHC-negative or IHC-equivocal result. Therefore, FISH should be performed in IHC-equivocal cases. FISH assay might be considered for a selected group of patients with IHC-negative tumors showing luminal B subtype features of ER-positive, grade II/III, and high Ki-67 expression.

Pharmacogenomic contribution to drug response

There has been significant progress made in individualizing cancer therapy, especially for colorectal and breast cancer. This has included objective determination of aggressiveness of therapy using molecular predictors of disease recurrence (i.e., Mammaprint, OncotypeDX), identifying altered drug activation for dose modifications (i.e., DPYD, CYP2D6, UGT1A1), or variation in drug targets or components of a pharmacodynamic pathway (TYMS, EGFR, KRAS). With patient-specific molecular characteristics increasingly guiding therapy, this review provides important and timely insights on targeted therapy. Ultimately, integration of both pharmacogenomic and clinical characteristics can provide powerful predictive tools for stratifying responders from nonresponders and identifying patients at increased risk for toxicity.

PiggyBac-mediated cancer immunotherapy using EBV-specific cytotoxic T-cells expressing HER2-specific chimeric antigen receptor

Epstein-Barr virus (EBV)-specific cytotoxic T lymphocytes (CTLs) can be modified to function as heterologous tumor directed effector cells that survive longer in vivo than tumor directed T cells without virus specificity, due to chronic stimulation by viral antigens expressed during persistent infection in seropositive individuals. We evaluated the nonviral piggyBac (PB) transposon system as a platform for modifying EBV-CTLs to express a functional human epidermal growth factor receptor 2-specific chimeric antigen receptor (HER2-CAR) thereby directing virus-specific, gene modified CTLs towards HER2-positive cancer cells. Peripheral blood mononuclear cells (PBMCs) were nucleofected with transposons encoding a HER2-CAR and a truncated CD19 molecule for selection followed by specific activation and expansion of EBV-CTLs. HER2-CAR was expressed in ~40% of T cells after CD19 selection with retention of immunophenotype, polyclonality, and function. HER2-CAR-modified EBV-CTLs (HER2-CTLs) killed HER2-positive brain tumor cell lines in vitro, exhibited transient and reversible increases in HER2-CAR expression following antigen-specific stimulation, and stably expressed HER2-CAR beyond 120 days. Adoptive transfer of PB-modified HER2-CTLs resulted in tumor regression in a murine xenograft model. Our results demonstrate that PB can be used to redirect virus-specific CTLs to tumor targets, which should prolong tumor-specific T cell survival in vivo producing more efficacious immunotherapy.

Identifying responders to trastuzumab therapy in breast cancer

In breast cancer, HER2-targeted therapy with trastuzumab has gained significant attention, owing to the dramatic response observed in a subset of HER2-positive patients. The mechanisms of action are complex and not fully understood, and much effort has been spent in order to identify responders. Good patient management, side effects of the humanized monoclonal antibody and socioeconomics all demand that the drug should be administered only to the patients who will benefit from it. This has been a difficult task and contributions to solve it have been proposed from a variety of research. In this article we describe some of these contributions based on the literature and provide our viewpoint as to which identifiers will emerge in the following decade.

Pathological characteristics of BRCA-associated breast cancers in Hispanics

The immunophenotype of BRCA-associated breast cancer has been studied in predominantly non-Hispanic whites (NHW). We evaluated the pathological characteristics of BRCA-associated invasive breast cancer in Hispanics. A case-control study was conducted on breast cancers from Hispanic and NHW women who enrolled in an IRB-approved registry and underwent BRCA gene analysis. BRCA negative controls (41 Hispanic, 39 NHW) were matched on age and ethnicity to BRCA positive cases (39 Hispanic, 35 NHW). A tissue array was constructed to characterize the expression of estrogen receptor (ER), progesterone receptor (PR), HER2, Ki-67 and p53 by immunohistochemistry. Mean age at diagnosis was 37.1 years (range 24-59) for Hispanics (80% with Mexican ancestry) and 40.1 years (range 21-63) for NHW (P = 0.03). Hispanic BRCA1 cases were more likely than BRCA negative controls to have tumors that were ER-negative (P < 0.001) and PR-negative (P = 0.001), had higher levels of Ki-67 (P = 0.001) and p53 expression, and lower levels of HER2 overexpression. When stratified by genes, there were no significant differences in expression of ER, Ki-67, HER2, and p53 by ethnicity among mutation carriers. However, a significantly higher proportion of BRCA-positive Hispanics had PR-negative tumors compared to BRCA-positive NHW (80 vs. 57%, OR = 2.9, 95% CI 1.0-8.1, P = 0.04). Hispanic BRCA-associated breast cancers were found to have the unique immunophenotype associated with BRCA mutations; however, there was a trend toward a difference in PR expression among Hispanic BRCA1 and BRCA2 cases. Additional research on the molecular mechanisms involved in the loss of PR in this population is warranted as it could have important implications for the treatment and prevention of breast cancer in Hispanics.

Trastuzumab emtansine (T-DM1): a novel agent for targeting HER2+ breast cancer

Increased understanding of the molecular mechanisms of tumorigenesis has led to the development of novel agents that target tumor cells with minimal effects on normal cells. The success of this approach is exemplified by the development of monoclonal antibodies directed toward antigens expressed selectively by tumor cells. The conjugation of these monoclonal antibodies with potent cytotoxic drugs has the potential to further improve efficacy while retaining a favorable safety profile. Trastuzumab emtansine (T-DM1) is an antibody-drug conjugate (ADC) currently in clinical development. It combines the humanized antibody trastuzumab, which targets the human epidermal growth factor receptor 2 (HER2) receptor on cancer cells, and the potent antimicrotubule agent DM1 using a unique highly stable linker. When T-DM1 binds to HER2, a proportion of the receptors are thought to be internalized by the process of receptor endocytosis, followed by the intracellular release of an active form of DM1, which in turn kills the tumor cell. This review presents the rationale for the development of T-DM1 and summarizes the preclinical and clinical data for this novel agent for the treatment of breast cancer.

Molecular assays in breast cancer pathology

Recent advances in understanding the molecular pathology of breast cancer offer significant potential to identify patients who may benefit from adjuvant therapies. To date, few of these advances are utilised in a routine setting. We review molecular assays that are currently in use or are in the advanced stages of development, which may be used as predictive or prognostic biomarkers in breast cancer.The only widely used breast cancer molecular assay is in situ hybridisation (ISH) for human epidermal growth factor receptor 2 (HER2) gene amplification and we highlight key issues with the interpretation of this assay, with particular attention to the difficulties of the equivocal category. New molecular assays such as ISH for the topoisomerase II alpha (TOP2A) gene and for the aberrations in the copy number of the centromeric region of chromosome 17 are readily performed in a standard histopathology laboratory, but to date there are insufficient data to support their routine use. We also review the current data on two commercially available multigene expression assays, Oncotype DX and MammaPrint and discuss their potential use. Overall, while new molecular assays have significant potential to improve patient selection for therapy, well-performed histopathology with reliable interpretation of standard hormone and HER2 assays provides the most important predictive and prognostic information in early breast cancer.

HER2 evaluation and its impact on breast cancer treatment decisions

BACKGROUND

Eighteen to twenty percent of breast cancer tumors show abnormal amplification of the Human Epidermal growth factor Receptor 2 (HER2) gene and increased expression of the associated protein. HER2 amplification is associated with rapid tumor proliferation and shorter disease-free and overall survival. Because women with HER2 amplification are more likely to benefit from treatment with the drug trastuzumab, testing for HER2 is recommended to guide therapy. However, little is known about use of HER2 testing in real-world settings. This study examined uptake, use, appropriateness of HER2 testing, and the relationship between HER2 test results and treatment decisions.

METHODS

We assessed electronic data from 3,634 patients with invasive breast cancer diagnosed from 1998 to 2007 in a large integrated health system. We collected data on patient and tumor characteristics, HER2 testing status, test results, and trastuzumab treatment.

RESULTS

From 1998 to 2000, the percent of patients who underwent HER2 evaluation increased from 12 to 94%; <3% of women with ductal carcinoma in situ, for whom HER2 testing is not recommended, were tested. Trastuzumab use increased 5-fold after 2004, when guidelines expanded to include recommending adjuvant treatment for early-stage breast cancer in addition to metastatic treatment. Ninety-five percent of women receiving trastuzumab had a positive HER2 result. After 2004, 55% of women with invasive breast cancer and overexpression of HER2 received trastuzumab treatment; this ranged from 44% of women with localized breast cancer to 80% of women with distant metastatic disease.

CONCLUSIONS

These findings illustrate appropriate and effective implementation of a HER2 testing strategy in a managed care setting.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Current technologies for HER2 testing in breast cancer

BACKGROUND

Molecular techniques play an increasingly important role in breast cancer detection and help in the prediction of prognosis and treatment response. HER-2/neu predicts the sensitivity of breast tumors to trastuzumab and lapatinib. Presently there are several ways to assess HER2 status at the protein level (e.g. ELISA), at the RNA level (RT-PCR, microarray) and at the DNA level (fluorescence in situ hybridization, chromogenic in situ hybridization (ISH), silver in situ hybridization or multiplex ligation-dependent probe amplification).

DESIGN

This paper provides an overview of new developments in HER2 testing.

RESULTS

Although these techniques correlate well in comparative studies, discrepancies remain. Each technique has its own (dis)advantages and thus there is no real gold standard. Not surprisingly, there is no consensus at present on which of the protein- or gene-based techniques is superior, on the use of mono- or duo-probe ISH systems, nor on the use of manual or fully-automated staining- and scoring systems.

CONCLUSION

Until large clinical trials clearly point out one strategy as the best predictive one for trastuzumab response, the choice for a testing strategy will probably be based on local preferences which consider both practical and economic issues. Standardization, proper internal and external quality control assessment, laboratory accreditation and automation of tissue processing (autostainers) and interpretation methods (image analysis) will play an increasingly important role in HER2 testing.

New strategies in HER2-overexpressing breast cancer: many combinations of targeted drugs available

The anti-HER2 drugs trastuzumab and lapatinib are increasingly changing the natural history of early and metastatic HER2-overexpressing breast cancer. Many other agents targeted against the HER2 signaling network are in clinical development, and these are or will soon be combined with the currently approved anti-HER2 therapies. We review herein recent data in support of the early use of combinations of agents targeted to the HER2 network as the most rational approach against this subtype of breast cancer. We propose that the optimal combination or combinations of anti-HER2 agents delivered early in the natural history of HER2+ breast cancer should close to eliminate acquired drug resistance, shorten the duration of therapy, and potentially dispense with the need of concurrent chemotherapy.

Targeted therapy for melanoma: a primer

Melanoma is the most aggressive form of skin cancer. Unfortunately, despite recent improvements for some solid tumors, the prevalence and mortality of melanoma continue to increase. The identification of activating mutations in melanoma, combined with a growing appreciation of the different pattern of genetic changes in the anatomically defined melanoma subtypes, has become the focus of a concerted effort to translate these discoveries into personalized therapeutic approaches for this disease. This article reviews the known mutations, amplifications, and deletions in kinase signaling pathways that have been implicated in melanoma; the prevalence of these genetic events in clinicopathologically defined melanoma subtypes; and the results of clinical trials that use targeted therapy approaches to block aberrantly activated pathways resulting from these mutations. The challenges that must be overcome to achieve improved outcomes with targeted therapies in melanoma in the future are also discussed.

Targeting a common collaborator in cancer development

In this issue of Science Translational Medicine, Wallin et al. have identified a subset of breast and ovarian cancer cell lines that show synergistic response to the combination of doxorubicin and GDC-0941, a class IA phosphatidylinositol 3-kinase (PI3K) inhibitor. Here, we discuss the potential implications of these data on the clinical development of PI3K pathway inhibitors as cancer therapeutics.

Testing for HER2 in Breast Cancer: A Continuing Evolution

Human epidermal growth factor receptor 2 (HER2) is an important prognostic and predictive factor in breast cancer. HER2 is overexpressed in approximately 15%–20% of invasive breast carcinomas and is associated with earlier recurrence, shortened disease free survival, and poor prognosis. Trastuzumab (Herceptin) a “humanized” monoclonal antibody targets the extracellular domain of HER2 and is widely used in the management of HER2 positive breast cancers. Accurate assessment of HER2 is thus critical in the management of breast cancer. The aim of this paper is to present a comprehensive review of HER2 with reference to its discovery and biology, clinical significance, prognostic value, targeted therapy, current and new testing modalities, and the interpretation guidelines and pitfalls.

Pathological complete response and survival according to the level of HER-2 amplification after trastuzumab-based neoadjuvant therapy for breast cancer

Background:

We analysed whether the level of human epidermal growth factor receptor-2 (HER-2) amplification significantly influenced either pathological complete response (pCR) or recurrence-free survival (RFS) and overall survival (OS) after trastuzumab-based neoadjuvant therapy.

Methods:

In all, 99 patients with an HER-2-amplified breast tumour treated with trastuzumab-based neoadjuvant therapy were included. Tumours were classified as low amplified (LA; 6–10 signals per nuclei) or highly amplified (HA; >10 signals). Pathological response was assessed according to Chevallier's classification (pCR was defined as grade 1 or 2). Median follow-up lasted 46 months (6–83). Cox uni- and multivariate analyses were performed.

Results:

In all, 33 tumour samples were LA and 66 were HA. The pCR in HA tumours was significantly higher than in LA tumours (55% vs 24%, P=0.005), whereas no association was found between the pCR rate and tumour stage, grade or hormone receptor status. In multivariate analysis, the pathological nodal status (P=0.005) and adjuvant trastuzumab (P=0.037) were independently associated with RFS, whereas the level of HER-2 amplification nearly reached statistical significance (P=0.057). There was no significant difference between LA and HA tumours for OS (P=0.22, log-rank).

Conclusion:

The level of HER-2 gene amplification significantly influenced pCR but not RFS or OS in non-metastatic breast cancer treated with trastuzumab-based neoadjuvant therapy. However, RFS in patients with HA tumours tended to be shorter.

HER3 mRNA as a predictive biomarker in anticancer therapy

IMPORTANCE OF THE FIELD

Heterodimerization of human EGF receptor (HER) 2 and HER3, a co-receptor of HER2, plays an important and dominant role in the functionality and transformation of HER-mediated pathways. Understanding the role of HER3 in oncogenesis as well as its place as a target for anticancer therapy is an ongoing area of research. Determination of biomarkers for clinical benefit from agents targeting HER3 is an essential component of translating basic science into real-world effective anticancer therapies, with the aim of ensuring the patients most likely to benefit from such treatments can be identified.

AREAS COVERED IN THIS REVIEW

This review focuses on the targeting of HER2 and HER3 by monoclonal antibodies and the potential for HER3 mRNA levels to predict treatment outcome in ovarian cancer.

WHAT THE READER WILL GAIN

An understanding of the value of biomarkers for clinical benefit to anticancer therapy and the current status of HER3 mRNA as a biomarker for clinical benefit of the HER2-HER3 dimerization inhibitor pertuzumab.

TAKE HOME MESSAGE

HER3 mRNA levels may be a biomarker for active ligand-induced HER2-HER3 signaling, with low HER3 mRNA levels correlated with clinical benefit from the HER2-HER3 dimerization inhibitor pertuzumab.

The reliability of rabbit monoclonal antibodies in the immunohistochemical assessment of estrogen receptors, progesterone receptors, and HER2 in human breast carcinomas

The reliability of the rabbit monoclonal antibodies SP1, SP2, SP3, and 4B5 was immunohistochemically assessed on a range of 96 invasive breast carcinomas and the results compared with those achieved with established antibody markers for estrogen receptors (6F11), progesterone receptors (PgR636), and HER2 (polyclonal A0485 and clone CB11), with HER2 status validated by fluorescence in situ hybridization (FISH) and silver in situ hybridization. Optimal results depended on the duration of microwave antigen-retrieval time and the use of a high pH buffer for rabbit and mouse estrogen receptor antibodies (SP1 and 6F11), although only on antigen-retrieval duration for the progesterone receptors SP2 and PgR636. The highest rate of concordance between HER2 overexpression and HER2 gene amplification was with the rabbit monoclonal antibodies (SP3 and 4B5) and FISH. Rabbit monoclonal antibodies are reliable alternatives to established antibody markers for the immunohistochemical testing of estrogen receptors, progesterone receptors, and HER2 in breast cancer.

High levels of topoisomerase IIalpha protein expression in diffuse large B-cell lymphoma are associated with high proliferation, germinal center immunophenotype, and response to treatment

Gene copy number and protein expression of topoisomerase IIalpha were correlated to benefit from anthracyclines in various tumors. A retrospective series of 69 patients with DLBCL managed with CHOP chemotherapy were studied for immunohistochemical TopoIIalpha expression and numerical gene abnormalities by fluorescent in situ hybridization (FISH). The results were analyzed in relation to the expression of cell cycle proteins (Ki67, p53, HDM2, p21, p14, pRb, p16, and cyclins A, B1, D1, D2, D3, and E) and BCL6/CD10/MUM1/CD138 B-cell differentiation immunophenotype and outcome. High levels of TopoIIalpha protein were found in 91% of DLBCL cases. No evidence of TopoIIalpha gene amplification or deletion was found. The TopoIIalpha expression showed significant positive correlations with the proliferation index Ki67 (p = 0.002), cell cycle proteins pRb and cyclin D2 (p = 0.018 and p = 0.028, respectively), and the germinal center proteins bcl6 and CD10 (p = 0.010 and p < 0.0001, respectively). TopoIIalpha expression was significantly higher in germinal center B-cell like (GCB) DLBCL than in non-germinal center B-cell like (non-GCB) DLBCL (p = 0.048). TopoIIalpha protein was significantly associated with response to chemotherapy (chi(2), p = 0.024), but not with relapse-free or overall survival (p = 0.5). On multivariate analysis, only stage of disease retained independent prognostic significance (HR 0.33 for early stage, p = 0.008). Although TopoIIa gene copy number abnormalities were not found in DLBCL, high levels of protein expression are associated with GCB-cell differentiation immunophenotype, high proliferation, and response to treatment.

Novel beta-lactamase-random peptide fusion libraries for phage display selection of cancer cell-targeting agents suitable for enzyme prodrug therapy

Novel phage-displayed random linear dodecapeptide (X(12)) and cysteine-constrained decapeptide (CX(10)C) libraries constructed in fusion to the amino-terminus of P99 beta-lactamase molecules were used for identifying beta-lactamase-linked cancer cell-specific ligands. The size and quality of both libraries were comparable to the standards of other reported phage display systems. Using the single-round panning method based on phage DNA recovery, we identified several beta-lactamase fusion peptides that specifically bind to live human breast cancer MDA-MB-361 cells. The beta-lactamase fusion to the peptides helped in conducting the enzyme activity-based clone normalization and cell-binding screening in a very time- and cost-efficient manner. The methods were suitable for 96-well readout as well as microscopic imaging. The success of the biopanning was indicated by the presence of approximately 40% cancer cell-specific clones among recovered phages. One of the binding clones appeared multiple times. The cancer cell-binding fusion peptides also shared several significant motifs. This opens a new way of preparing and selecting phage display libraries. The cancer cell-specific beta-lactamase-linked affinity reagents selected from these libraries can be used for any application that requires a reporter for tracking the ligand molecules. Furthermore, these affinity reagents have also a potential for their direct use in the targeted enzyme prodrug therapy of cancer.

Confirmation of a low HER2 positivity rate of breast carcinomas - limitations of immunohistochemistry and in situ hybridization

Background

Accurate assessment of the human epidermal growth factor receptor 2 (HER2) of invasive breast cancer is essential to treatment decisions since the advent of targeted therapy with the humanized monoclonal antibody trastuzumab and the dual tyrosine kinase inhibitor lapatinib. In the literature, the percentage of HER2-overexpressed/amplified breast carcinomas range from 3% to 30%. The routinely assigned low rate of 9% of HER2-overexpressed breast carcinomas alarmed one of our gynecologists who requested to confirm our HER2 test results.

Methods

A small study of 83 patients with breast carcinoma was designed to reexamine the routinely assessed HER2 status using immunohistochemistry and fluorescence in situ hybridization.

Results

The low rate of 9% of HER2-overexpressed/amplified breast tumors (DIN1C-3, invasive carcinoma) could be confirmed. However, FISH revealed two false positive cases and one false negative case. Moreover a case with an equivocal result in FISH was detected.

Conclusion

The HER2 positivity rate may be as low as 9%. The novel ASCO/CAP criteria for assessing immunohistochemical results in HER 2 testing reduce the false positive rate of HER2. First-line testing with immunohistochemistry may obscure false positive and false negative test results. In heterogeneous carcinomas even fluorescence in situ hybridization may not succeed in a correct evaluation of HER2.

Reliability of Human Epidermal Growth Factor Receptor 2 Immunohistochemistry in Breast Core Needle Biopsies

Purpose

Core needle biopsies (CNBs) are widely used to determine human epidermal growth factor receptor 2 (HER2) status in breast cancer. Recent publications reported up to 20% false-positive results on CNBs if immunohistochemistry (IHC) is compared with fluorescent in situ hybridization (FISH). To clarify, if confirmation of IHC positivity by FISH is generally required, we analyzed the reliability of IHC positivity on CNBs versus surgical specimens in a multi-institutional study.

Patients and Methods

Five pathologic laboratories contributed to this study by performing IHC on 500 CNBs and the corresponding surgical specimens overall. If IHC revealed score 2+ or 3+, HER2 status was confirmed by FISH in a central laboratory. We compared evaluation according to US Food and Drug Administration–approved scoring criteria and recently published American Society of Clinical Oncology (ASCO)–College of American Pathologists (CAP) guidelines.

Results

CNBs scored 3+ revealed five false-positive results if scoring followed the US Food and Drug Administration criteria (five of 40; 12.5%) and two false-positives in terms of the ASCO-CAP criteria (two of 33; 6.1%). IHC was false negative in one CNB only. By contrast, IHC on surgical specimens revealed five false-negative results, but only one false-positive result (one of 35; 2.9%) if scored following US Food and Drug Administration–approved criteria. With the aid of the ASCO-CAP criteria, false-positive IHC results were obtained in only one of the five participating institutions.

Conclusion

IHC 3+ scores on CNBs proved to be reliable in four of the five participating institutions if scoring followed the ASCO-CAP criteria. Therefore, accurate determination of HER2 status in breast cancer is possible on CNB using the common strategy to screen all cases by IHC and retest only 2+ scores by FISH. Prerequisites are quality assurance and the application of the new ASCO-CAP criteria.

Genetic and expression analysis of HER-2 and EGFR genes in salivary duct carcinoma: empirical and therapeutic significance

PURPOSE

Salivary duct carcinoma overexpresses epidermal growth factor receptor (EGFR) and HER-2, although the underlying mechanisms remain undefined. Because of the potential utilization of these markers as treatment targets, we evaluated protein and gene status by several techniques to determine complementary value.

EXPERIMENTAL DESIGN

A tissue microarray of 66 salivary duct carcinomas was used for immunohistochemical analysis of HER-2 and EGFR expression (semiquantitatively evaluated into a three-tiered system), and fluorescence in situ hybridization for gene copy number, and chromosomes 7 and 17 ploidy status. Sequencing of exons 18, 19, and 21 of the EGFR gene for mutations was carried out.

RESULT

For EGFR, 46 (69.7%) of the 66 tumors showed some form of EGFR expression (17 at 3+, 17 at 2+, 12 at 1+) but none gene amplification. Five (9.4%) of 53 tumors showed mutations in exon 18 (n = 3) and exon 19 (n = 2). Polysomy of chromosome 7 (average >2.5 copies/cell) was detected in 15 (25.0%) of 60 tumors (6 at 3+, 5 at 2+, 2 at 1+, 2 at 0+ expression) and correlated with poor 3-year survival (P = 0.015). For HER-2, 17 (25.8%) of 66 tumors expressed HER-2 (10 at 3+, 3 at 2+, 4 at 1+). Eight tumors showed HER-2 gene amplification (6 at 3+, 1 at 1+, 1 at 0+ protein expression). Chromosome 17 polysomy was found in 8 (15.7%) of 51 tumors; two had HER-2 expression (3+, 1+).

CONCLUSION

Our study shows that salivary duct carcinomas (a) harbor EGFR gene mutations in a subset of tumors that may guide therapy, (b) pursue an aggressive clinical course in cases with chromosome 7 polysomy and high EGFR expression, and (c) with HER-2 gene amplification and protein high expression, may be selected for targeted therapy.

Should adjuvant trastuzumab be offered in very early-stage (pT1a/bN0M0) HER2-neu-positive breast cancer? A current debate

There are many controversies regarding the treatment of very early-stage (pT1a/bN0M0) breast cancer (BC), generally considered to have a very good prognosis. The debate is the benefit of an adjuvant treatment of HER2-neu (namely HER-2)-positive subcentimetric carcinoma with trastuzumab. Current guidelines do not suggest, with the highest level of evidence, whether trastuzumab should be administered after adjuvant chemotherapy in the treatment of high-risk pT1a/bN0M0 breast cancer. The major phase III trials that confirmed the benefit of adjuvant immunotherapy did not include small (<1 cm diameter) node-negative breast cancer. Several retrospective case series of HER-2-positive pT1a/bN0M0 carcinoma seem to demonstrate that they have a higher risk of relapse compared to the HER-2-negative counterpart. HER-2 also seems to confer an independent risk of recurrence and/or death in a multivariate analysis within large node-negative breast cancer populations. In particular, the best way to select higher-risk tumours that may achieve the best results from a trastuzumab-based therapy appears to be the in situ hybridization, which should follow the new recommended algorithm of the ASCO/CAP guidelines in case of doubtful results. According to the evidence that the survival of HER-2-positive BC can be improved with the introduction of trastuzumab respect to the HER-2-negative counterpart, there is today less uncertainty about the curative role of anti-HER-2 therapy in very early disease.

Frequent PIK3CA gene amplification and its clinical significance in colorectal cancer

Using a DNA microarray approach to screen for gene copy number changes in 20 colorectal (CR) carcinoma samples and filtering for high-level DNA copy number changes, we detected an amplicon at 3q26 containing the PIK3CA gene. Fluorescence in situ hybridization was employed for evaluation of PIK3CA amplification on a progression CR tissue microarray containing 448 CR carcinomas, normal mucosa, and adenomas with follow-up information. PIK3CA amplification (ratio PIK3CA/centromere 3 > or = 2.0) was found in 38% of cancers, while another 19% of tumours had PIK3CA gains (ratio >1.0 but <2.0). Both PIK3CA amplification and gains were associated with high levels of PIK3CA protein expression and no association was seen between PIK3CA amplification and PIK3CA mutation. In a subset of 220 patients who received adjuvant chemotherapy and/or radiotherapy, survival in patients with PIK3CA-amplified cancers was significantly longer compared with patients with cancers without amplification. This association was independent of stage, grade, histology subtype, gender, and age categories. Interestingly, PIK3CA amplification was also seen in CR adenomas, indicating an early genetic alteration, and was also a frequent event in colorectal carcinogenesis. Furthermore, PIK3CA amplification is an independent prognostic marker for better survival and may be one of the promising markers to define CRC subsets that may maximally benefit from adjuvant therapy.

[Tumors of the urinary system. Current and old problems]

Principally there are two different types of bladder cancer. Non-invasive papillary low grade tumors (pTa G1-G2) are genetically stable, recur frequently but show a low risk of progression. On the other hand there are high grade tumors (pT1-4, carcinoma in situ), which are genetically unstable, show biologically aggressive behaviour and progress. The distinction between non-invasive (pTa) and minimal-invasive (pT1) is one of the most challenging areas in bladder pathology. Due to the lack of appropriate auxiliary analysis the diagnosis is based entirely on histopathology. P53 immunohistochemistry can be helpful in the assessment of recurring high grade neoplasia. Targeted therapy in bladder cancer is particularly interesting, since a high number of oncogenes are activated and overexpressed (e.g. HER2 and EGFR).

Predictive genomic biomarkers

Advances in the biological characterization of tumors has led to the design and development of anticancer agents targeting specific molecular alterations. The majority of these agents are designed to silence phosphorylation signals that are required for the development and maintenance of the cancer phenotype in specific tumor types. Prospective identification of cancer subsets containing particular target alterations is a requirement for these development programs, which in theory, should include smaller trials and result in larger therapeutic benefits. In this review, we will examine relevant examples of selection markers effectively utilized in oncology, and discuss important considerations pertaining to the co-development of drugs and diagnostics, including current regulatory paths, the incorporation of selection markers emerging late in development, and future directions in the area of personalized oncology.

Pharmacogenetics in reproductive and perinatal medicine

The clinical application of pharmacogenetics has been well accepted by some medical specialties, but not all. The aim of this review is to discuss the current use of pharmacogenetics in reproductive and perinatal medicine and to highlight areas where pharmacogenetics may be able to help in the future to predict response to medicines in terms of efficacy and safety. This applies to drugs that are specific to pregnancy and reproduction, as well as drugs prescribed for the treatment of medical disorders in pregnancy. Our review points out the need for well-designed clinical studies on the efficacy and safety of medicines used in women of childbearing age in order to define the additional utility provided by pharmacogenetic testing.

A census of amplified and overexpressed human cancer genes

Integrated genome-wide screens of DNA copy number and gene expression in human cancers have accelerated the rate of discovery of amplified and overexpressed genes. However, the biological importance of most of the genes identified in such studies remains unclear. In this Analysis, we propose a weight-of-evidence based classification system for identifying individual genes in amplified regions that are selected for during tumour development. In a census of the published literature we have identified 77 genes for which there is good evidence of involvement in the development of human cancer.

Management of HER2-positive breast cancer in Asia: consensus statement from the Asian Oncology Summit 2009

Patients with breast cancer positive for human epidermal growth-factor receptor type 2 (HER2) are an important subgroup for consideration in the Asian context. Rationally designed, anti-HER2 targeted agents that can substantially improve treatment outcomes have become commercially available, but are still too costly for some groups in developed countries and for underdeveloped and developing nations. This review discusses the available evidence for optimum management of HER2-positive early and advanced breast cancer, and how this evidence can be applied to Asian countries with different levels of health-care resources and economic development--using framework provided by the Breast Health Global Initiative. We provide a brief overview of HER2 testing and discuss management of early and advanced HER2-positive breast cancer, and formulate a consensus statement for the management of breast cancer in the context of basic, limited, enhanced, and maximum health-care resource availability.

Personalized Cancer Therapy With Selective Kinase Inhibitors: An Emerging Paradigm in Medical Oncology

Selective kinase inhibitors have emerged as an important class of anticancer agents, with demonstrated clinical efficacy and generally favorable toxicity profiles in several common disease settings where conventional treatments have previously provided only modest benefit. Consequently, a substantial effort is now underway to identify additional therapeutically relevant kinase targets and to develop and test inhibitors of those proteins in a variety of human malignancies. However, it has also become clear that the clinical benefit associated with these agents is typically limited to a subset of treated patients, who in many cases are defined by a specific genomic lesion within their tumor cells—frequently, an activating mutation within the gene encoding the target kinase. This discovery has prompted efforts to stratify patients before treatment with kinase inhibitors based on specific genomic biomarkers, with the goal of optimizing clinical outcomes through the effective personalization of treatment (ie, matching the right patients with the right therapies). With recent advances in our understanding of the relationship between tumor genotypes and cancer cell sensitivity to kinase inhibition, together with improved technologies for rapidly genotyping tumor biopsies for relevant lesions, the implementation of personalized cancer care with this exciting new class of inhibitors is now becoming a reality. In this review, we summarize recent developments in this area, and we highlight some of the logistical challenges posed by this emerging paradigm in medical oncology.

Comparison of immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) assessment for Her-2 status in breast cancer

Background

The concordance rate between IHC and FISH according to clinical performance is still controversial. We report a prospective study to reflect the concordance between IHC and FISH in Guilin city, People's Republic of China.

Methods

Fifty cases of invasive ductal carcinoma of breast tested by IHC and scored as 0, 1+, 2+ and 3+ by pathologists were further analyzed by FISH using a commercially available double-color probe, and the FISH findings were compared with IHC test results.

Results

A total concordance of 82.0% was observed with a Kappa coefficient of 0.640 (P < 0.001). A high discordance was observed in 30.0% of the patients with IHC 2+, 7.1% in IHC 3+, 19.2% overall in IHC 0 and 1+.

Conclusion

The IHC can be used firstly to screen the HER-2 status, and FISH can be used as a supplementary role to IHC and 2+ and some negative cases. And only those cases with Her-2 status of IHC 3+ or FISH positive should be treated with Herceptin.