The Impact of Partial Weak Staining in Normal Breast Epithelium on the Reliability of Immunohistochemistry Results in HercepTest-positive Breast Cancer

INTRODUCTION

Although normal epithelial cells do not show human epidermal growth factor receptor-2 (HER2) gene amplification and should lack membrane staining by HER2 immunohistochemistry (IHC), HER2 staining in benign breast epithelium is occasionally encountered. The significance of this occurrence has not yet been adequately studied, and its associated American Society of Clinical Oncology/College of American Pathologists recommendations are vague. Our objective is to assess the correlation between HER2 IHC 3+ breast cancer cases with normal epithelium staining (NES) and their corresponding fluorescence in situ hybridization (FISH) results, and to suggest recommendations for interpretation.

MATERIALS AND METHODS

A total of 154 breast cancer cases with HER2 IHC 3+ were reviewed. NES, along with other clinicopathologic characteristics, were recorded. NES was scored as present or absent. All study cases were sent for FISH testing. All cases, and particularly those that showed false positivity for IHC (positive IHC, negative FISH) were examined for NES.

RESULTS

Of the 154 cases, 146 cases were FISH-positive (94.8%) and 2 failed FISH testing (1.3%). Conversely, 22% (34/154) of the cases showed NES for HER2. Of these 34 cases, 23 (67%) were FISH-amplified, 9 (26%) were FISH not amplified, and 2 failed FISH testing. Notably, all of the false-positive (FISH-negative) breast cancer cases showed some degree of positivity in normal breast epithelium.

CONCLUSIONS

Our findings, though descriptive, show a very strong association between NES and false-positive HER2 IHC. This confirms the need to carefully evaluate IHC-positive breast cancers for NES, and to have a low threshold for confirmatory testing by FISH.

HER2 Directed Antibody-Drug-Conjugates beyond T-DM1 in Breast Cancer

Since the discovery of the human epidermal growth factor receptor 2 (HER2) as an oncogenic driver in a subset of breast cancers and the development of HER2 directed therapies, the prognosis of HER2 amplified breast cancers has improved meaningfully. Next to monoclonal anti-HER2 antibodies and tyrosine kinase inhibitors, the antibody-drug conjugate T-DM1 is a pillar of targeted treatment of advanced HER2-positive breast cancers. Currently, several HER2 directed antibody-drug conjugates are under clinical investigation for HER2 amplified but also HER2 expressing but not amplified breast tumors. In this article, we review the current preclinical and clinical evidence of the investigational drugs A166, ALT-P7, ARX788, DHES0815A, DS-8201a, RC48, SYD985, MEDI4276 and XMT-1522.

HER2 amplification level is not a prognostic factor for HER2-positive breast cancer with trastuzumab-based adjuvant treatment: a systematic review and meta-analysis

Background

Trastuzumab-based therapy is a standard, targeted treatment for HER2-positive breast cancer in the adjuvant setting. However, patients do not benefit equally from it and the association between HER2 amplification level and patients' survival remains controversial. A systematic review and meta-analysis was conducted by incorporating all available evidence to evaluate the association between disease free survival (DFS) and HER2 amplification level.

Results

Three cohort studies involving 1360 HER2-positive breast cancer patients stratified by HER2 amplification magnitude were eligible for meta-analysis. The combined HRs for DFS were 1.05 (95% CI: 0.80−1.36, p = 0.74) and 0.97 (95% CI: 0.73−1.29, p = 0.83) for HER2 gene copy number (GCN) and HER2/CEP 17 ratio. No evidence of heterogeneity or public bias was found.

Methods

Databases including PubMed, Embase, Web of Science, and Cochrane Central Register of Controlled Trials (CENTRAL), were searched for eligible literature. HER2 amplification level was evaluated by fluorescence in situ hybridization (FISH) in terms of gene copy number (GCN) and HER2/CEP17 ratio. Hazard ratios (HRs) for DFS with 95% confidence interval (CI) according to the amplification level of HER2 were extracted. The outcomes were synthesized based on a fixed-effects model.

Conclusions

HER2 amplification level is not a prognostic factor for HER2-positive breast cancer with trastuzumab-based targeted therapy in the clinical adjuvant setting.

Clinical utility of RT-PCR in assessing HER 2 gene expression versus traditional IHC and FISH in breast cancer patients

BACKGROUND

IHC and FISH are used for categorizing HER 2 status in breast cancer at the protein and DNA level, respectively. HER 2 expression at the RNA level is quantitative, cheaper, easier to standardize and free from interobserver variation.

METHODS

115 consecutive patients were tested by IHC, FISH and RT-PCR (test cohort). Assuming FISH result to be the response variable, ROC curves for RT-PCR ratio were analyzed to label HER 2 negative, equivocal and positive cases as RT-PCR score 1, 2 and 3, respectively. Inter-relationships between RT-PCR, IHC and FISH were defined. 'Clinical benefit' of a test was defined as proportion of patients labeled unequivocally as HER 2 positive or negative. Population for 1 year was simulated constraint to previous reports of HER 2 positivity and IHC category distribution by a meta-analysis of previous studies that evaluated concordance between IHC and FISH to determine HER 2 status (simulation cohort). Four diagnostic pathways in the simulation cohort were defined-(1) initial IHC, followed by FISH (conventional pathway); (2) initial RT-PCR, followed by FISH; (3) initial IHC, followed by RT-PCR and then by FISH; (4) initial RT-PCR, followed by IHC and then by FISH. The clinical benefit of IHC and RT-PCR in the four pathways was analyzed and sensitivity analysis for incremental cost-effectiveness ratio and cost-benefit comapring RT-PCR against IHC, both as first-line tests and among those with IHC score 2 as a reflex second-line test was performed by the Monte Carlo technique.

FINDINGS

115 patients comprised the study population. While none with IHC score of 0 or 1 was FISH positive for HER 2, all cases with IHC score of 3 were FISH positive. 43 cases were assigned IHC score of 2. Thus, 72 patients benefited from the initial IHC testing [clinical benefit 62.6%], with the overall concordance between IHC and FISH being 100% for those with IHC score of 0, 1 and 3 (conclusive IHC categories). For RT-PCR with 100% concordance, 15.7% (115-97 = 18) patients would have benefited from RT-PCR testing if it was used as a first-line test. If RT-PCR would have been used as a second-line test among those with IHC score 2 (n = 43), then only 6 patients would have been assigned a conclusive RT-PCR category (category 1 or 3) translating to a clinical benefit of 14% (6/43) as a second-line test. As a second-line test it had 51% probability to prove more cost-effective than the conventional pathway, provided the cost of RT-PCR was 0.4 times the cost of IHC. Also in a three-step pathway, RT-PCR upfront would have 56% probability of higher cost-benefit provided the cost of RT-PCR was 0.1 times the cost of IHC.

CONCLUSION

RT-PCR results were found to be suboptimal to IHC in terms of discriminative ability and clinical benefit; thus, it is unlikely to replace IHC as a first-line test in the near future.

Her2 assessment using quantitative reverse transcriptase polymerase chain reaction reliably identifies Her2 overexpression without amplification in breast cancer cases

BACKGROUND

Immunohistochemistry (IHC) and fluorescent-in situ hybridization (FISH) are standard methods to assess human epidermal growth factor receptor 2 (HER2) status in breast cancer (BC) patients. Real-time quantitative polymerase-chain-reaction (qRT-PCR) is able to detect HER2 overexpression. Here we compared FISH, IHC, quantitative PCR (qPCR), and qRT-PCR to determine the concordance rates and evaluate their relative roles in HER2 determination.

PATIENTS AND METHODS

We determined HER2 status in 153 BC patients, using IHC, FISH, Q-PCR and qRT-PCR. In discordant cases, we directly measured HER2 protein levels using Western blotting.

RESULTS

The overall agreement (OA) between FISH and Q-PCR was 94.1, with a k value of 0.87. Assuming FISH as the standard reference, Q-PCR showed an 86.1% sensitivity and a 99.0% specificity with a global accuracy of 91.6%. OA between FISH and qRT-PCR was 90.8% with a k value of 0.81. Of interest, the disagreement between FISH and qRT-PCR was mostly restricted to equivocal cases. HER2 protein analysis suggested that qRT-PCR correlates better than FISH with HER2 protein levels, particularly where FISH fails to provide conclusive results.

SIGNIFICANCE

qRT-PCR may outperform FISH in identifying patients overexpressing HER2 protein. Q-PCR cannot be used for HER2 status assessment, due to its suboptimal level of agreement with FISH. Both FISH and Q-PCR may be less accurate than qRT-PCR as surrogates of HER2 protein determination.

The relationship between quantitative human epidermal growth factor receptor 2 gene expression by the 21-gene reverse transcriptase polymerase chain reaction assay and adjuvant trastuzumab benefit in Alliance N9831

Introduction

The N9831 trial demonstrated the efficacy of adjuvant trastuzumab for patients with human epidermal growth factor receptor 2 (HER2) locally positive tumors by protein or gene analysis. We used the 21-gene assay to examine the association of quantitative HER2 messenger RNA (mRNA) gene expression and benefit from trastuzumab.

Methods

N9831 tested the addition of trastuzumab to chemotherapy in stage I–III HER2-positive breast cancer. For two of the arms of the trial, doxorubicin and cyclophosphamide followed by paclitaxel (AC-T) and doxorubicin and cyclophosphamide followed by paclitaxel and trastuzumab concurrent chemotherapy-trastuzumab (AC-TH), recurrence score (RS) and HER2 mRNA expression were determined by the 21-gene assay (Oncotype DX®) (negative <10.7, equivocal 10.7 to <11.5, and positive ≥11.5 log₂ expression units). Cox regression was used to assess the association of HER2 expression with trastuzumab benefit in preventing distant recurrence.

Results

Median follow-up was 7.4 years. Of 1,940 total patients, 901 had consent and sufficient tissue. HER2 by reverse transcriptase polymerase chain reaction (RT-PCR) was negative in 130 (14 %), equivocal in 85 (9 %), and positive in 686 (76 %) patients. Concordance between HER2 assessments was 95 % for RT-PCR versus central immunohistochemistry (IHC) (>10 % positive cells = positive), 91 % for RT-PCR versus central fluorescence in situ hybridization (FISH) (≥2.0 = positive) and 94 % for central IHC versus central FISH. In the primary analysis, the association of HER2 expression by 21-gene assay with trastuzumab benefit was marginally nonsignificant (nonlinear p = 0.057). In hormone receptor-positive patients (local IHC) the association was significant (p = 0.002). The association was nonlinear with the greatest estimated benefit at lower and higher HER2 expression levels.

Conclusions

Concordance among HER2 assessments by central IHC, FISH, and RT-PCR were similar and high. Association of HER2 mRNA expression with trastuzumab benefit as measured by time to distant recurrence was nonsignificant. A consistent benefit of trastuzumab irrespective of mHER2 levels was observed in patients with either IHC-positive or FISH-positive tumors. Trend for benefit was observed also for the small groups of patients with negative results by any or all of the central assays.

Trial registration

Clinicaltrials.gov NCT00005970. Registered 5 July 2000.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-015-0643-7) contains supplementary material, which is available to authorized users.

Antiproliferative Effect of Lapatinib in HER2-Positive and HER2-Negative/HER3-High Breast Cancer: Results of the Presurgical Randomized MAPLE Trial (CRUK E/06/039)

PURPOSE

Not all breast cancers respond to lapatinib. A change in Ki67 after short-term exposure may elucidate a biomarker profile for responsive versus nonresponsive tumors.

EXPERIMENTAL DESIGN

Women with primary breast cancer were randomized (3:1) to 10 to 14 days of preoperative lapatinib or placebo in a multicenter phase II trial (ISRCTN68509377). Biopsies pre-/posttreatment were analyzed for Ki67, apoptosis, HER2, EGFR, ER, PgR, pAKT, pERK, and stathmin by IHC. Further markers were measured by RT-PCR. Primary endpoint was change in Ki67. HER2(+) was defined as 2+/3+ by IHC and FISH(+).

RESULTS

One hundred twenty-one patients (lapatinib, 94; placebo, 27) were randomized; of these, 21% were HER2(+), 78% were HER2(-) nonamplified, 26% were EGFR(+). Paired samples containing tumor were obtained for 98% (118 of 121). Ki67 fell significantly with lapatinib (-31%; P < 0.001), but not with placebo (-3%). Whereas Ki67 reduction with lapatinib was greatest in HER2(+) breast cancer (-46%; P = 0.003), there was a significant Ki67 decrease in HER2(-) breast cancer (-27%; P = 0.017) with 14% of HER2(-) breast cancer demonstrating ≥50% Ki67 reduction with lapatinib. Among HER2(+) patients, the only biomarker predictive of Ki67 response was the EGFR/HER4 ligand epiregulin (EREG) (rho = -0.7; P = 0.002). Among HER2(-) tumors, only HER3 mRNA levels were significantly associated with Ki67 response on multivariate analysis (P = 0.01). In HER2(-) breast cancer, HER2 and HER3 mRNA levels were highly correlated (rho = 0.67, P < 0.001), with all Ki67 responders having elevated HER3 and HER2 expression.

CONCLUSIONS

Lapatinib has antiproliferative effects in a subgroup of HER2(-) nonamplified tumors characterized by high HER3 expression. The possible role of high HER2:HER3 heterodimers in predicting response to lapatinib merits investigation in HER2(-) tumors.

Predictive biomarkers in colorectal cancer: usage, validation, and design in clinical trials

As cancer treatment development has shifted its attention to targeted therapies, it is becoming increasingly important to provide tools for selecting the right treatment for an individual patient to achieve optimal clinical benefit. Biomarkers, identified and studied in the process of understanding the nature of the disease at the molecular pathogenesis level, have been increasingly recognized as a critical aspect in more accurate diagnosis, prognosis assessment, and therapeutic targeting. Predictive biomarkers, which can aid treatment decisions, require extensive data for validation. In this article, we discuss the definition, clinical usages, and more extensively the clinical trial designs for the validation of predictive biomarkers. Predictive biomarker validation methods can be broadly grouped into retrospective and prospective designs. Retrospective validation utilizes data from previously conducted prospective randomized controlled trials. Prospective designs include enrichment designs, treatment-by-marker interaction designs, marker-based strategy designs, and adaptive designs. We discuss each design with examples and provide comparisons of the advantages and disadvantages among the different designs. We conclude that the combination of scientific, clinical, statistical, ethical, and practical considerations provides guidance for the choice of the clinical trial design for validation of each proposed predictive biomarker.

A new gene expression signature, the ClinicoMolecular Triad Classification, may improve prediction and prognostication of breast cancer at the time of diagnosis

Introduction

When making treatment decisions, oncologists often stratify breast cancer (BC) into a low-risk group (low-grade estrogen receptor-positive (ER+)), an intermediate-risk group (high-grade ER+) and a high-risk group that includes Her2+ and triple-negative (TN) tumors (ER-/PR-/Her2-). None of the currently available gene signatures correlates to this clinical classification. In this study, we aimed to develop a test that is practical for oncologists and offers both molecular characterization of BC and improved prediction of prognosis and treatment response.

Methods

We investigated the molecular basis of such clinical practice by grouping Her2+ and TN BC together during clustering analyses of the genome-wide gene expression profiles of our training cohort, mostly derived from fine-needle aspiration biopsies (FNABs) of 149 consecutive evaluable BC. The analyses consistently divided these tumors into a three-cluster pattern, similarly to clinical risk stratification groups, that was reproducible in published microarray databases (n = 2,487) annotated with clinical outcomes. The clinicopathological parameters of each of these three molecular groups were also similar to clinical classification.

Results

The low-risk group had good outcomes and benefited from endocrine therapy. Both the intermediate- and high-risk groups had poor outcomes, and their BC was resistant to endocrine therapy. The latter group demonstrated the highest rate of complete pathological response to neoadjuvant chemotherapy; the highest activities in Myc, E2F1, Ras, β-catenin and IFN-γ pathways; and poor prognosis predicted by 14 independent prognostic signatures. On the basis of multivariate analysis, we found that this new gene signature, termed the "ClinicoMolecular Triad Classification" (CMTC), predicted recurrence and treatment response better than all pathological parameters and other prognostic signatures.

Conclusions

CMTC correlates well with current clinical classifications of BC and has the potential to be easily integrated into routine clinical practice. Using FNABs, CMTC can be determined at the time of diagnostic needle biopsies for tumors of all sizes. On the basis of using public databases as the validation cohort in our analyses, CMTC appeared to enable accurate treatment guidance, could be made available in preoperative settings and was applicable to all BC types independently of tumor size and receptor and nodal status. The unique oncogenic signaling pathway pattern of each CMTC group may provide guidance in the development of new treatment strategies. Further validation of CMTC requires prospective, randomized, controlled trials.

Clinical significance of epidermal growth factor receptors in non-small cell lung cancer and a prognostic role for HER2 gene copy number in female patients

INTRODUCTION

To compare the efficacy of silver in situ hybridization (SISH) and immunohistochemistry (IHC) in detecting HER2 alterations and to investigate the prevalence and prognostic significance of Erb family members in non-small cell lung cancer (NSCLC).

METHODS

Stage I to IIIA tumors from 335 patients with NSCLC were immunohistochemically tested for protein expression of all Erb family members. Membranous HER2 expression was compared with its gene copy number by SISH in paraffin-embedded, formalin-fixed material. Correlations were made with clinicopathological variables.

RESULTS

Synchronous high immunohistochemical expression of all Erb family members was seen in 8% of tumor samples. There was a significant correlation between the HER2 gene copy number and HER2 protein expression (p = 0.003). High nuclear HER3 expression correlated significantly with high HER2 gene copy numbers (p = 0.015). In univariate analyses, high HER2 gene copy number was a highly significant negative prognostic indicator for disease-specific survival in women (p = 0.005), whereas it did not show prognostic influence in men (p = 0.9). Neither polysomy of chromosome 17 nor the IHC expression of Erb family member proteins as singles or pairs correlated significantly with survival. In the multivariate analysis, high HER2 gene copy number in tumor epithelial cells (p = 0.03) was an independent prognostic factor for disease-specific survival in female patients.

CONCLUSIONS

IHC does not consistently identify patients likely to have a poor prognosis, whereas SISH provides superior prognostic information for female patients with NSCLC. High HER2 gene copy number in tumor epithelial cells is an independent predictor of inferior survival in female patients with primary NSCLC.

Traditional molecular markers and response to adjuvant endocrine or trastuzumab-based therapies

PURPOSE OF REVIEW

The accurate assessment of traditional molecular markers is essential to inform the choice of the adjuvant systemic treatments for patients with breast cancer. Extensive research efforts have been made to explore whether it is also possible to predict the actual response to the different therapeutic options based on the expression of these markers.

RECENT FINDINGS

Endocrine responsiveness of breast cancer has been eventually defined according to the expression of estrogen receptors in at least 1% of invasive tumor cells. The quantitative evaluation of estrogen receptors, progesterone receptors (PgR) and Ki-67 labeling index may help in selecting patients with estrogen receptor-positive and HER2-negative tumors who can be spared or may benefit from the addition of chemotherapy to endocrine therapy. Guideline recommendations for an optimal testing of estrogen receptors and PgR have been issued to assist pathologists in the accurate assessment of these markers. Progress has also been made in the identification of candidate patients to HER2-targeted therapies and in the prediction of response to trastuzumab.

SUMMARY

Traditional molecular markers play a major role in the selection of candidate patients to systemic interventions, but they are of limited value in predicting their actual response to the different treatments, especially when the markers are evaluated individually.

HER2 and chromosome 17 effect on patient outcome in the N9831 adjuvant trastuzumab trial

PURPOSE

We examined associations between tumor characteristics (human epidermal growth factor receptor 2 [HER2] protein expression, HER2 gene and chromosome 17 copy number, hormone receptor status) and disease-free survival (DFS) of patients in the N9831 adjuvant trastuzumab trial.

PATIENTS AND METHODS

All patients (N = 1,888) underwent chemotherapy with doxorubicin and cyclophosphamide, followed by weekly paclitaxel with or without concurrent trastuzumab. HER2 status was determined by immunohistochemistry (IHC) and fluorescent in situ hybridization (FISH) at a central laboratory, Mayo Clinic, Rochester, MN. Patients with conflicting local positive HER2 expression results but normal central laboratory testing were included in the analyses (n = 103).

RESULTS

Patients with HER2-positive tumors (IHC 3+, FISH HER2/centromere 17 ratio ≥ 2.0, or both) benefited from trastuzumab, with hazard ratios (HRs) of 0.46, 0.49, and 0.45, respectively (all P < .0001). Patients with HER2-amplified tumors with polysomic (p17) or normal (n17) chromosome 17 copy number also benefited from trastuzumab, with HRs of 0.52 and 0.37, respectively (P < .006). Patients who received chemotherapy alone and had HER2-amplified and p17 tumors had a longer DFS than those who had n17 (78% v 68%; P = .04), irrespective of hormone receptor status or tumor grade. Patients with HER2-normal tumors by central testing (n = 103) seemed to benefit from trastuzumab, but the difference was not statistically significant (HR, 0.51; P = .14). Patients with hormone receptor-positive or -negative tumors benefited from the addition of trastuzumab, with HRs of 0.42 (P = .005) and 0.60 (P = .0001), respectively.

CONCLUSION

These results confirm that IHC or FISH HER2 testing is appropriate for patient selection for adjuvant trastuzumab therapy. Trastuzumab benefit seemed independent of HER2/centromere 17 ratio and chromosome 17 copy number.

Predictive biomarker validation in practice: lessons from real trials

BACKGROUND

With the advent of targeted therapies, biomarkers provide a promising means of individualizing therapy through an integrated approach to prediction using the genetic makeup of the disease and the genotype of the patient. Biomarker validation has therefore become a central topic of discussion in the field of medicine, primarily due to the changing landscape of therapies for treatment of a disease and these therapies purported mechanism(s) of action.

PURPOSE

In this report, we discuss the merits and limitations of some of the clinical trial designs for predictive biomarker validation using examples from ongoing or completed clinical trials.

METHODS

The designs are broadly classified as retrospective (i.e., using data from previously well-conducted randomized controlled trials (RCT)) versus prospective (enrichment or targeted, unselected or all-comers, hybrid, and adaptive analysis). We discuss some of these designs in the context of real trials.

RESULTS

Well-designed retrospective analysis of prospective RCT can bring forward effective treatments to marker defined subgroup of patients in a timely manner. An example is the KRAS gene status in colorectal cancer - the benefit from cetuximab and panitumumab was demonstrated to be restricted to patients with wild type status based on prospectively specified analyses using data from previously conducted RCTs. Prospective enrichment designs are appropriate when compelling preliminary evidence suggests that not all patients will benefit from the study treatment under consideration; however, this may sometimes leave questions unanswered. An example is the established benefit of trastuzumab as adjuvant therapy for breast cancer; a clear definition of HER2-positivity and the assay reproducibility have, however, remained unanswered. An all-comers design is optimal where preliminary evidence regarding treatment benefit and assay reproducibility is uncertain (e.g., EGFR expression and tyrosine kinase inhibitors in lung cancer), or to identify the most effective therapy from a panel of regimens (e.g., chemotherapy options in breast cancer).

LIMITATIONS

The designs discussed here rest on the assumption that the technical feasibility, assay performance metrics, and the logistics of specimen collection are well established and that initial results demonstrate promise with regard to the predictive ability of the marker(s).

CONCLUSIONS

The choice of a clinical trial design is driven by a combination of scientific, clinical, statistical, and ethical considerations. There is no one size fits all solution to predictive biomarker validation.

Biomarkers and surrogate end points--the challenge of statistical validation

Biomarkers and surrogate end points have great potential for use in clinical oncology, but their statistical validation presents major challenges, and few biomarkers have been robustly confirmed. Provisional supportive data for prognostic biomarkers, which predict the likely outcome independently of treatment, is possible through small retrospective studies, but it has proved more difficult to achieve robust multi-site validation. Predictive biomarkers, which predict the likely response of patients to specific treatments, require more extensive data for validation, specifically large randomized clinical trials and meta-analysis. Surrogate end points are even more challenging to validate, and require data demonstrating both that the surrogate is prognostic for the true end point independently of treatment, and that the effect of treatment on the surrogate reliably predicts its effect on the true end point. In this Review, we discuss the nature of prognostic and predictive biomarkers and surrogate end points, and examine the statistical techniques and designs required for their validation. In cases where the statistical requirements for validation cannot be rigorously achieved, the biological plausibility of an end point or surrogate might support its adoption. No consensus yet exists on processes or standards for pragmatic evaluation and adoption of biomarkers and surrogate end points in the absence of robust statistical validation.

Simultaneous detection of TOP2A and HER2 gene amplification by multiplex ligation-dependent probe amplification in breast cancer

HER-2/neu gene amplification, found in certain subtypes of (breast-) cancers, is an independent prognostic factor of poor outcome and determines eligibility for systemic treatment with trastuzumab. TopoII alpha (TOP2A) gene amplification seems to be predictive of response to a class of cytostatic agents called TopoII inhibitors, which include the anthracyclines. The observed increased efficacy of anthracyclines in HER2-positive tumors is thought to arise from the close proximity of both genes on chromosome 17, where the TopoII amplification status will determine the anthracycline sensitivity. This study aimed to validate a new polymerase chain reaction-based test, called multiplex ligation-dependent probe amplification (MLPA), as a simple and quick method to simultaneously assess HER-2/neu and TopoII alpha gene amplification status in paraffin-embedded breast cancer samples. To this end, MLPA results were compared with TopoII alpha, HER2 chromogenic in situ hybridization (CISH). We also assessed TopoII alpha protein expression by immunohistochemistry. Of 353 patients, 9% showed TopoII alpha amplification by MLPA and 13% of patients were HER2 amplified. TopoII alpha amplification was seen in 42% of HER2-amplified cases and showed no high level amplification without HER2 amplification. Eleven patients displayed TopoI alpha loss (3%). Concordance between MLPA and CISH was 91% for TopoII alpha and 96% for HER2. Correlation between amplification and overexpression of TopoII alpha was significant (P=0.035), but amplification did not always predict protein overexpression. Loss of the TopoII alpha gene was almost never associated with loss of its protein. In conclusion, MLPA is an easy and accurate method to simultaneously detect breast cancer HER-2/neu and TopoII alpha copy number status in paraffin-embedded tissue, and thus an attractive supplement or alternative to CISH.

Clinical practice patterns and cost effectiveness of human epidermal growth receptor 2 testing strategies in breast cancer patients

BACKGROUND

Testing technologies are increasingly used to target cancer therapies. Human epidermal growth factor receptor 2 (HER2) testing to target trastuzumab for patients with breast cancer provides insights into the evidence needed for emerging testing technologies.

METHODS

The authors reviewed literature on HER2 test utilization and cost effectiveness of HER2 testing for patients with breast cancer. They examined available evidence on: percentage of eligible patients tested for HER2; test methods used; concordance of test results between community and central/reference laboratories; use of trastuzumab by HER2 test result; and cost effectiveness of testing strategies.

RESULTS

Little evidence was available to determine whether all eligible patients are tested, how many are retested to confirm results, and how many with negative HER2 test results still receive trastuzumab. Studies suggested that up to 66% of eligible patients had no documentation of testing in claims records, up to 20% of patients receiving trastuzumab were not tested or had no documentation of a positive test, and 20% of HER2 results may be incorrect. Few cost-effectiveness analyses of trastuzumab explicitly considered the economic implications of various testing strategies.

CONCLUSIONS

There was little information about the actual use of HER2 testing in clinical practice, but evidence suggested important variations in testing practices and key gaps in knowledge exist. Given the increasing use of targeted therapies, it is critical to build an evidence base that supports informed decision making on emerging testing technologies in cancer care.

Be precise! The need to consider the mechanisms for CEP17 copy number changes in breast cancer

A recent paper by Marchiò and colleagues indicated that true polysomy of chromosome 17 is rare and that coincident CEP 17 centromere amplification may account for its overestimation in FISH testing for HER2 amplification, with a treat/not treat decision as the final important readout. Here the importance of relating HER2 copy number to cell count rather than a ratio with CEP17 is emphasized. This is central to ensuring that all who may respond to potentially life-saving treatment with herceptin/lapatininib are not denied these drugs.

Clinical trial designs for predictive biomarker validation: theoretical considerations and practical challenges

PURPOSE

Biomarkers can add substantial value to current medical practice by providing an integrated approach to prediction using the genetic makeup of the tumor and the genotype of the patient to guide patient-specific treatment selection. We discuss and evaluate various clinical trial designs for the validation of biomarker-guided therapy.

METHODS

Designs for predictive marker validation are broadly classified as retrospective (ie, using data from previously well-conducted randomized controlled trials [RCTs]) versus prospective (enrichment, unselected, hybrid, or adaptive analysis). We discuss the salient features of each design in the context of real trials.

RESULTS

Well-designed retrospective analysis from well-conducted prospective RCTs can bring forward effective treatments to marker-defined subgroups of patients in a timely manner (eg, KRAS and colorectal cancer). Enrichment designs are appropriate when preliminary evidence suggest that patients with or without that marker profile do not benefit from the treatments in question; however, this may sometimes leave questions unanswered (eg, trastuzumab and breast cancer). An unselected design is optimal where preliminary evidence regarding treatment benefit and assay reproducibility is uncertain (eg, epidermal growth factor receptor and lung cancer). Hybrid designs are appropriate when preliminary evidence demonstrate the efficacy of certain treatments for a marker-defined subgroup, making it unethical to randomly assign patients with that marker status to other treatments (eg, multigene assay and breast cancer). Adaptive analysis designs allow for prespecified marker-defined subgroup analyses of data from an RCT.

CONCLUSION

The implementation of these design strategies will lead to a more rapid clinical validation of biomarker-guided therapy.

Clinical trial designs for predictive biomarker validation: one size does not fit all

Traditionally, anatomic staging systems have been used to provide predictions of individual patient outcome and, to a lesser extent, guide the choice of treatment in cancer patients. With targeted therapies, biomarkers have the potential for providing added value through an integrated approach to prediction using the genetic makeup of the tumor and the genotype of the patient for treatment selection and patient management. Specifically, biomarkers can aid in patient stratification (risk assessment), treatment response identification (surrogate markers), or differential diagnosis (identifying individuals who are likely to respond to specific drugs). In this study, we explore two major topics in relation to the design of clinical trials for predictive marker validation. First, we discuss the appropriateness of an enrichment (i.e., targeted) vs. an unselected design through case studies focusing on the clinical question(s) at hand, the strength of the preliminary evidence, and assay reproducibility. Second, we evaluate the efficiency (total number of events and sample size) of two unselected predictive marker designs for validation of a marker under a wide range of clinically relevant scenarios, exploring the impact of the prevalence of the marker and the hazard ratios for the treatment comparisons. The review and evaluation of these designs represents an essential step toward the goal of personalized medicine because we explicitly seek to explore and evaluate the methodology for the clinical validation of biomarker guided therapy.

Estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2 (HER2), and epidermal growth factor receptor expression and benefit from lapatinib in a randomized trial of paclitaxel with lapatinib or placebo as first-line treatment in HER2-negative or unknown metastatic breast cancer

PURPOSE

Lapatinib is a dual inhibitor of epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2) with activity in HER2-amplified metastatic breast cancer (MBC). Its role in non-HER2-amplified MBC remains unclear. EGF30001, a phase III trial of lapatinib and paclitaxel versus paclitaxel and placebo, demonstrated lapatinib does not significantly benefit HER2-negative or HER2-unselected patients with MBC. Published data support interactions between steroid hormone and peptide growth factor signaling. We hypothesized that molecular subgroups may exist within EGF30001 that would benefit from lapatinib.

METHODS

A blinded, retrospective biomarker evaluation was performed using immunohistochemistry to semiquantitate estrogen (ER), progesterone (PR), and EGFR expression. HER2 amplification was determined by fluorescent in situ hybridization. Effects of these biomarkers on event-free survival (EFS) were examined in patients with available tissue (n = 493).

RESULTS

Lapatinib improved median EFS in HER2-amplified, ER- or PR-positive MBC (n = 36; 5.7 v 4.5 months; P = .351); benefit was greater and statistically significant in HER2-amplified, ER-negative, PR-negative MBC (n = 42; 8.3 v 5.0 months; P = .007). In HER2-negative, ER-positive MBC, median EFS improvement varied by degree of PR expression (H-score): no benefit if PR-strong (n = 133; 9.3 v 7.3 months; P = .373), benefit if PR-weak (n = 50; 7.3 v 2.4 months; P = .026), and potential antagonism if PR-negative (n = 40; 3.7 v 7.2 months; P = .004). No benefit was seen in triple-negative MBC (n = 131; median EFS, 4.6 v 4.8 months; P = .255). EGFR expression was not correlated with benefit from lapatinib.

CONCLUSION

Although subgroups are small, these analyses support the hypothesis that semiquantitative determination of hormone receptor status may be a surrogate for EGFR and/or HER2 dependency.

Disease-free survival according to degree of HER2 amplification for patients treated with adjuvant chemotherapy with or without 1 year of trastuzumab: the HERA Trial

PURPOSE

To determine whether (1) immunohistochemical (IHC) HER2 status (ie, 2+ or 3+), (2) degree of fluorescence in situ hybridization (FISH) amplification according to (2a) HER2/CEP17 ratio or (2b) HER2 gene copy number, or (3) polysomy significantly influenced clinical outcome for patients with human epidermal growth factor receptor 2 (HER2) -positive breast cancer enrolled in the Herceptin Adjuvant trial of trastuzumab versus no trastuzumab administered after completion of chemotherapy.

PATIENTS AND METHODS

IHC and/or FISH analyses were performed locally and required central confirmation as indicating HER2 positivity for trial entry. FISH data from the central HER2 analysis on patients in the 1-year trastuzumab and no trastuzumab arms were assessed in relation to disease-free survival (DFS) after a median 2 years of follow-up.

RESULTS

Central FISH results were available for 2,071 (61%) of the 3,401 patients randomized to the 2 arms. Among patients with FISH-positive disease, (1) the hazard ratios for trastuzumab versus no trastuzumab were 0.56 (95% CI, 0.32 to 0.99) for locally IHC2+ cases (n = 340) and 0.80 (95% CI, 0.40 to 1.61) for centrally IHC2+ cases (n = 299). There was no significant prognostic relationship between (2a) HER2 FISH ratio, (2b) HER2 copy number, or (3) polysomy and DFS in the control arm or predictive relationship defining differential benefit from trastuzumab.

CONCLUSION

There was no evidence for reduced benefit of trastuzumab in HER2 IHC2+FISH+ cases. The degree of HER2 amplification does not influence prognosis or benefit from adjuvant trastuzumab in patients treated with prior adjuvant chemotherapy.

Comparison of quantitative immunofluorescence with conventional methods for HER2/neu testing with respect to response to trastuzumab therapy in metastatic breast cancer

CONTEXT

Selection for trastuzumab therapy depends on a companion diagnostic assessment of HER2 by either immunohistochemistry (IHC) for protein overexpression or fluorescence in situ hybridization (FISH) to detect gene amplification. Although many studies have compared IHC to FISH, few have compared the tests to the true gold standard, tumor response.

OBJECTIVE

To compare HER2 testing by FISH and IHC along with a third immunofluorescence-based assay (automated quantitative analysis-tissue microarray [AQUA-TMA]) and to assess the value of each test for prediction of response to trastuzumab.

DESIGN

Immunohistochemistry and FISH assays were done on both whole slides (IHC-WS and FISH-WS) and on TMAs (IHC-TMA and FISH-TMA). AQUA was only done on TMAs (AQUA-TMA). Response was assessed according to modified Response Evaluation Criteria in Solid Tumors.

RESULTS

AQUA-TMA scores showed a significant linear relationship to both the FISH signal ratio and IHC scores on whole sections and TMAs. Assay assessment by outcome showed no association between response and FISH-WS ratio (P = .96), FISH-TMA (P = .55), IHC-WS (P = .75), or IHC-TMA (P = .06), but a significant relationship between AQUA score and categoric response was observed (P = .01). Assessed as a function of outcome using models of logistic regression, both AQUA-TMA and IHC-TMA were equally significant (P = .01). FISH-WS was the most sensitive assay, with a significantly higher true-positive fraction than all other tests except AQUA-TMA, although it was the least specific. IHC-TMA was the most specific assay. The lowest misclassification rate was achieved using AQUA-TMA (0.30).

CONCLUSIONS

Both AQUA-TMA and IHC-TMA were substantially more predictive than the FISH or IHC-WS tests. Although these results are derived from a small retrospective series, they suggest that accurate measurement of protein expression and unbiased selection of tissue for measurement may be key factors in prediction of response.

Prognostic value of the molecular detection of circulating tumor cells using a multimarker reverse transcription-PCR assay for cytokeratin 19, mammaglobin A, and HER2 in early breast cancer

PURPOSE

To investigate the prognostic value of the molecular detection of circulating tumor cells (CTCs) using three markers [cytokeratin 19 (CK19), mammaglobin A (MGB1), and HER2] in early breast cancer.

EXPERIMENTAL DESIGN

CK19mRNA+, MGB1mRNA+, and HER2mRNA+ cells were detected using real-time (CK19) and nested (MGB1 and HER2) reverse transcription-PCR in the peripheral blood of 175 women with stage I to III breast cancer before the initiation of adjuvant chemotherapy. The detection of CTCs was correlated with clinical outcome. In 10 patients, immunofluorescence staining experiments were done to investigate the coexpression of cytokeratin, MGB1, and HER2 in CTCs.

RESULTS

CK19mRNA+, MGB1mRNA+, and HER2mRNA+ cells were detected in 41.1%, 8%, and 28.6% of the 175 patients, respectively. Patients had one of the following molecular profiles: CK19mRNA+/MGB1mRNA+/HER2mRNA+ (n = 8), CK19mRNA+/MGB1mRNA+/HER2mRNA- (n = 1), CK19mRNA+/MGB1mRNA-/HER2mRNA+ (n = 42), CK19mRNA+/MGB1mRNA-/HER2mRNA- (n = 21), CK19mRNA-/MGB1mRNA+/HER2mRNA- (n = 5), and CK19mRNA-/MGB1mRNA-/HER2mRNA- (n = 98). Double-immunofluorescence experiments confirmed the following CTC phenotypes: CK+/MGB1+, CK+/MGB1-, CK-/MGB1+, CK+/HER2+, CK+/HER2-, MGB1+/HER2-, and MGB1+/HER2+. In univariate analysis, the detection of CK19mRNA+, MGB1mRNA+, and HER2mRNA+ cells was associated with shorter disease-free survival (DFS; P < 0.001, P = 0.001, and P < 0.001, respectively), whereas the detection of CK19mRNA+ and MGB1mRNA+ cells was associated with worse overall survival (P = 0.044 and 0.034, respectively). In multivariate analysis, estrogen receptor-negative tumors and the detection of CK19mRNA+ and MGB1mRNA+ cells were independently associated with worse DFS.

CONCLUSION

The detection of peripheral blood CK19mRNA+ and MGB1mRNA+ cells before adjuvant chemotherapy predicts poor DFS in women with early breast cancer.

Neuregulins and cancer

The neuregulins represent the largest subclass of polypeptide factors of the epidermal growth factor family of ligands. These molecules are synthesized as membrane-bound, biologically active growth factors that act by binding to the HER/ErbB receptor tyrosine kinases. Preclinical data have indicated that increased expression and function of neuregulins may provoke cancer. Furthermore, neuregulin expression has been detected in several neoplasias, and their presence may correlate with response to treatments that target the HER receptors such as trastuzumab. In addition, the neuregulins have also been implicated in resistance to anti-HER therapies. Therefore, targeting of the neuregulins may be helpful in neoplastic diseases in which these polypeptide factors contribute to tumor generation and/or maintenance.

Trastuzumab as adjuvant therapy for early breast cancer: the importance of accurate human epidermal growth factor receptor 2 testing

CONTEXT

Overexpression of human epidermal growth factor receptor 2 (HER2) is an adverse prognostic parameter for patients with breast cancer. Patients with HER2-positive tumors are, however, likely to gain significant benefit from targeted therapy with trastuzumab. Four large-scale trials have assessed the efficacy and safety of adjuvant trastuzumab. In all 4 trials, disease-free survival and overall survival were significantly improved with adjuvant trastuzumab (36%-52% and 33%-41%, respectively), and improvements were observed in all patient subgroups.

OBJECTIVE

To describe, in detail, the clinical benefits of using trastuzumab in the adjuvant setting, and to emphasize the importance this places on the pathologist to correctly identify all patients with HER2-positive tumors with a high degree of accuracy.

DATA SOURCES

Published literature on both HER2 testing and the adjuvant use of trastuzumab.

CONCLUSIONS

Immunohistochemistry and/or fluorescence in situ hybridization are routinely used to determine HER2 status. Maintaining quality assurance throughout a standardized testing process is essential to achieve accurate and reproducible assay results. Adherence to the new American Society of Clinical Oncology/College of American Pathologists HER2 testing guidelines will help to ensure correct identification of all patients who may benefit from adjuvant trastuzumab and has significant implications for patient outcomes.

Co-targeting insulin-like growth factor I receptor and HER2: dramatic effects of HER2 inhibitors on nonoverexpressing breast cancer

The insulin-like growth factor I receptor (IGFIR) and HER2 display important signaling interactions in breast cancer. We examined the effect of combinations of antagonists of these receptors using two human breast cancer cell lines: BT474 (HER2+, IGFIR low) and MCF7 (HER2 low, IGFIR high). In BT474 cells, growth was inhibited by HER2 antagonists but not by IGFIR antagonists; however, IGFIR antagonists enhanced the effect of HER2 inhibitors. In MCF7 cells, growth was inhibited by IGFIR antagonists but not by HER2 antagonists; however, HER2 antagonism enhanced the effect of IGFIR inhibitors. Synergistic inhibition of soft agar growth was also observed. Although HER2 and IGFIR antagonists individually only minimally affected cell cycle, their combination gave a small enhancement of their effects. No single receptor-targeting drug was capable of inducing apoptosis, but combining antagonists of both receptors induced a dramatic degree of apoptosis in both cell lines. Induction of apoptosis was most striking in MCF7 cells using a Herceptin/IGFIR antagonist combination despite these cells being HER2 nonoverexpressing. Toward understanding the mechanism of these effects, we detected coassociation IGFIR and HER2 in both cell lines. Specific inhibitors of one of these receptors could cross-inhibit the activity of the other. Targeting both receptors gave the maximal inhibition of their downstream extracellular signal-regulated kinase 1/2 and AKT signaling pathways. Hence, such drug combinations may be clinically useful and may be beneficial even in tumors in which single drugs are inactive, as exemplified by the effect of the HER2/IGFIR inhibitor combination in HER2 nonoverexpressing MCF7 cells.

Randomized phase III trial of weekly compared with every-3-weeks paclitaxel for metastatic breast cancer, with trastuzumab for all HER-2 overexpressors and random assignment to trastuzumab or not in HER-2 nonoverexpressors: final results of Cancer and Leukemia Group B protocol 9840

PURPOSE

Phase II trials suggested that weekly paclitaxel might be more effective and less toxic than every-3-weeks administration for metastatic breast cancer (MBC). Cancer and Leukemia Group B (CALGB) protocol 9840 was initiated to address this question. Subsequently trastuzumab was demonstrated to improve outcomes of paclitaxel therapy for human epidermal growth factor receptor-2 (HER-2)-positive patients, and was therefore incorporated. Because inhibition of HER-family signaling had potential efficacy even without HER-2 overexpression, we randomly assigned for trastuzumab in this population.

PATIENTS AND METHODS

Patients were randomly assigned to paclitaxel 175 mg/m(2) every 3 weeks or 80 mg/m(2) weekly. After the first 171 patients, all HER-2-positive patients received trastuzumab; HER-2 nonoverexpressors were randomly assigned for trastuzumab, in addition to paclitaxel schedule. A total of 577 patients were treated on 9840. An additional 158 patients were included in analyses, for combined sample of 735. The primary end point was response rate (RR); secondary end points were time to progression (TTP), overall survival, and toxicity. Primary comparisons were between weekly versus every-3-weeks paclitaxel, and trastuzumab versus no trastuzumab in HER-2 nonoverexpressors.

RESULTS

In the combined sample, weekly paclitaxel was superior to every-3-weeks administration: RR (42% v 29%, unadjusted odds ratio [OR] = 1.75; P = .0004), TTP (median, 9 v 5 months; adjusted HR = 1.43; P < .0001), and survival (median, 24 v 12 months; adjusted HR = 1.28; P = .0092). For HER-2 nonoverexpressors, trastuzumab did not improve efficacy. Grade 3 neuropathy was more common with weekly dosing (24% v 12%; P = .0003).

CONCLUSION

Weekly paclitaxel is more effective than every-3-weeks administration for MBC. Trastuzumab did not improve efficacy for HER-2 nonoverexpressors. Neurotoxicity is a treatment-limiting toxicity for weekly paclitaxel.

New cutpoints to identify increased HER2 copy number: analysis of a large, population-based cohort with long-term follow-up

BACKGROUND

HER2 gene amplification and/or protein overexpression in breast cancer is associated with a poor prognosis and predicts response to anti-HER2 therapy. We examine the natural history of breast cancers in relationship to increased HER2 copy numbers in a large population-based study.

PATIENTS AND METHODS

HER2 status was measured by fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) in approximately 1,400 breast cancer cases with greater than 15 years of follow-up. Protein expression was evaluated with two different commercially-available antibodies.

RESULTS

We looked for subgroups of breast cancer with different clinical outcomes, based on HER2 FISH amplification ratio. The current HER2 ratio cut point for classifying HER2 positive and negative cases is 2.2. However, we found an increased risk of disease-specific death associated with FISH ratios of >1.5. An 'intermediate' group of cases with HER2 ratios between 1.5 and 2.2 was found to have a significantly better outcome than the conventional 'amplified' group (HER2 ratio >2.2) but a significantly worse outcome than groups with FISH ratios less than 1.5.

CONCLUSION

Breast cancers with increased HER2 copy numbers (low level HER2 amplification), below the currently accepted positive threshold ratio of 2.2, showed a distinct, intermediate outcome when compared to HER2 unamplified tumors and tumors with HER2 ratios greater than 2.2. These findings suggest that a new cut point to determine HER2 positivity, at a ratio of 1.5 (well below the current recommended cut point of 2.2), should be evaluated.

Hot topics and landmark studies from the 43rd annual meeting of the American Society of Clinical Oncology

The results of several preclinical and clinical studies were reported by oncology professionals at the 43rd American Society of Clinical Oncology (ASCO) meeting, the largest international forum in which the latest achievements in cancer research are annually presented. The central theme this year was 'Translating Research into Practice', emphasizing the goal of forging stronger links between basic research and clinical practice. This review offers a critical, summarized selection of several of the foremost studies presented at the meeting. The focus is on the findings from randomized phase III trials that, in the authors' opinion, are most likely to have an immediate effect on clinical practice.

HER2 targeted therapy in breast cancer...beyond Herceptin

HER2, is a member of the ErbB family of receptor tyrosine kinases, that plays a key role in the pathogenesis of breast cancer, and when overexpressed, can correlate with a particularly aggressive clinical phenotype. It is estimated in roughly 18 to 20% of breast cancer patients, there is amplification of the HER2 gene resulting in aberrant overexpression of p185HER2 protein. As such, HER2 represents an attractive therapeutic target. In this review, we explore the clinical evolution of trastuzumab, a humanized monoclonal antibody with high specificity and affinity for the HER2 extracellular domain, and additionally examine more recent efforts targeting the intracellular tyrosine kinase domain of HER2 using small molecule tyrosine kinase inhibitors.