Human epidermal growth factor receptor 2 testing: where are we?

Refining the definition of HER2-low class in invasive breast cancer

BACKGROUND

Emerging evidence indicates that breast cancer (BC) patients whose tumours express HER2 protein without HER2 gene amplification (HER2-low), can benefit from antibody-drug conjugates (ADC). However, the current definition of HER2-low BC remains incomplete with low rates of concordance. This study aims to refine HER2-low definition with emphasis on distinguishing HER2 score 0 from score 1+ to identify patients who are eligible for ADC.

METHODS

A BC cohort (n = 363) with HER2 IHC scores 0, 1+ and 2+ (without HER2 gene amplification) and available HER2 mRNA was included. HER2 staining intensity, pattern and subcellular localisation were reassessed. Artificial neural network analysis was applied to cluster the cohort and to distinguish HER2 score 0 from 1+. Reproducibility and reliability of the refined criteria were tested.

RESULTS

HER2 IHC score 1+ was refined as membranous staining in invasive cells as either: (1) faint intensity in ≥ 20% of cells regardless the circumferential completeness, (2) weak complete staining in ≤ 10%, (3) weak incomplete staining in > 10% and (4) moderate incomplete staining in ≤ 10%. Based on this, 63% of the HER2-negative cases were reclassified as positive (HER2-low). The refined score showed perfect observer agreement compared to the moderate agreement in the original clinical scores. Similar results were generated when the refined score was applied on the independent BC cohorts. A proposal to refine the definition of other HER2 classes is presented.

CONCLUSION

This study refined the definition of HER2-low BC based on correlation with HER2 mRNA and distinguished between HER2 IHC score 1+ and score 0 tumours.

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.

In situ hybridization to detect and localize signature cytokines of T-helper (Th) 1 and Th2 immune responses in chicken tissues

The avian immune system has been shown to possess a repertoire of cytokines directing T-helper (Th) 1 and Th2 types of immune responses similar to that in mammals. The objective of this study was to establish in situ hybridization (ISH) for the localization of mRNA of selected signal cytokines, chicken interferon-γ (ChIFN-γ), chicken interleukin (ChIL)-4 and ChIL-13 in fixed tissues. RNA probes were generated to hybridize to 488, 318, and 417bp of the respective target mRNA. Probe concentrations ranging from 100ng/ml to 400ng/ml were shown to be suitable to label cells that expressed these cytokines. The specificity of every probe was verified using the respective sense probe. ChIFN-γ, ChIL-4 and ChIL-13 positive cells were observed in the lymphocytic infiltrations of liver and in the periarteriolar lymphatic sheaths of spleen collected from specific-pathogen-free chickens. ISH of these cytokines in a severely inflamed liver due to infiltration with the parasite Histomonas meleagridis revealed the expression of both ChIFN-γ and ChIL-13 mRNA in the mononuclear infiltrates. In conclusion, ChIFN-γ, ChIL-4 and ChIL-13 mRNA were efficiently localized by ISH, which supplies a valid technique to characterize immune responses in fixed tissues.

Estrogen receptor alpha (ESR1)-signaling regulates the expression of the taxane-response biomarker PRP4K

The pre-mRNA splicing factor 4 kinase PRP4K (PRPF4B), is an essential kinase that is a component of the U5 snRNP and functions in spliceosome assembly. We demonstrated that PRP4K is a novel biological marker for taxane response in ovarian cancer patients and reduced levels of PRP4K correlate with intrinsic and acquired taxane resistance in both breast and ovarian cancer. Breast cancer treatments are chosen based on hormone and growth factor receptor status, with HER2 (ERBB2) positive breast cancer patients receiving anti-HER2 agents and taxanes and estrogen receptor alpha (ESR1) positive (ER+) breast cancer patients receiving anti-estrogen therapies such as tamoxifen. Here we demonstrate that PRP4K is expressed in the normal mammary duct epithelial cells of the mouse, and that estrogen induces PRP4K gene and protein expression in ER+ human MCF7 breast cancer cells. Estrogen acts through ESR1 to regulate PRP4K expression, as over-expression of ESR1 in the ER-negative MDA-MB-231 breast cancer cell line increased the expression of this kinase, and knock-down of ESR1 in ER+ T47D breast cancer cells reduced PRP4K levels. Furthermore, treatment with 4-hydroxytamoxifen (4-OHT) resulted in a dose-dependent decrease in PRP4K protein expression in MCF7 cells. Consistent with our previous studies identifying PRP4K as a taxane-response biomarker, reduced PRP4K expression in 4-OHT-treated cells correlated with reduced sensitivity to paclitaxel. Thus, PRP4K is novel estrogen regulated kinase, and its levels can be reduced by 4-OHT in ER+ breast cancer cells altering their response to taxanes.

Free digital image analysis software helps to resolve equivocal scores in HER2 immunohistochemistry

Evaluation of human epidermal growth factor receptor 2 (HER2) immunohistochemistry (IHC) is subject to interobserver variation and lack of reproducibility. Digital image analysis (DIA) has been shown to improve the consistency and accuracy of the evaluation and its use is encouraged in current testing guidelines. We studied whether digital image analysis using a free software application (ImmunoMembrane) can assist in interpreting HER2 IHC in equivocal 2+ cases. We also compared digital photomicrographs with whole-slide images (WSI) as material for ImmunoMembrane DIA. We stained 750 surgical resection specimens of invasive breast cancers immunohistochemically for HER2 and analysed staining with ImmunoMembrane. The ImmunoMembrane DIA scores were compared with the originally responsible pathologists' visual scores, a researcher's visual scores and in situ hybridisation (ISH) results. The originally responsible pathologists reported 9.1 % positive 3+ IHC scores, for the researcher this was 8.4 % and for ImmunoMembrane 9.5 %. Equivocal 2+ scores were 34 % for the pathologists, 43.7 % for the researcher and 10.1 % for ImmunoMembrane. Negative 0/1+ scores were 57.6 % for the pathologists, 46.8 % for the researcher and 80.8 % for ImmunoMembrane. There were six false positive cases, which were classified as 3+ by ImmunoMembrane and negative by ISH. Six cases were false negative defined as 0/1+ by IHC and positive by ISH. ImmunoMembrane DIA using digital photomicrographs and WSI showed almost perfect agreement. In conclusion, digital image analysis by ImmunoMembrane can help to resolve a majority of equivocal 2+ cases in HER2 IHC, which reduces the need for ISH testing.

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.

Comparative study between quantitative digital image analysis and fluorescence in situ hybridization of breast cancer equivocal human epidermal growth factor receptors 2 score 2(+) cases

Background:

Optimization of workflow for breast cancer samples with equivocal human epidermal growth factor receptors 2 (HER2)/neu score 2⁺ results in routine practice, remains to be a central focus of the on-going efforts to assess HER2 status. According to the College of American Pathologists/American Society of Clinical Oncology guidelines equivocal HER2/neu score 2⁺ cases are subject for further testing, usually by fluorescence in situ hybridization (FISH) investigations. It still remains on open question, whether quantitative digital image analysis of HER2 immunohistochemistry (IHC) stained slides can assist in further refining the HER2 score 2⁺.

Aim of this Work:

To assess utility of quantitative digital analysis of IHC stained slides and compare its performance to FISH in cases of breast cancer with equivocal HER2 score 2⁺.

Materials and Methods:

Fifteen specimens (previously diagnosed as breast cancer and was evaluated as HER 2^- score 2⁺) represented the study population. Contemporary new cuts were prepared for re-evaluation of HER2 immunohistochemical studies and FISH examination. All the cases were digitally scanned by iScan (Produced by BioImagene [Now Roche-Ventana]). The IHC signals of HER2 were measured using an automated image analyzing system (MECES, www.Diagnomx.eu/meces). Finally, a comparative study was done between the results of the FISH and the quantitative analysis of the virtual slides.

Results:

Three out of the 15 cases with equivocal HER2 score 2⁺, turned out to be positive (3⁺) by quantitative digital analysis, and 12 were found to be negative in FISH too. Two of these three positive cases proved to be positive with FISH, and only one was negative.

Conclusions:

Quantitative digital analysis is highly sensitive and relatively specific when compared to FISH in detecting HER2/neu overexpression. Therefore, it represents a potential reliable substitute for FISH in breast cancer cases, which desire further refinement of equivocal IHC results.

Evidence of clinical utility: an unmet need in molecular diagnostics for patients with cancer

This article defines and describes best practices for the academic and business community to generate evidence of clinical utility for cancer molecular diagnostic assays. Beyond analytical and clinical validation, successful demonstration of clinical utility involves developing sufficient evidence to demonstrate that a diagnostic test results in an improvement in patient outcomes. This discussion is complementary to theoretical frameworks described in previously published guidance and literature reports by the U.S. Food and Drug Administration, Centers for Disease Control and Prevention, Institute of Medicine, and Center for Medical Technology Policy, among others. These reports are comprehensive and specifically clarify appropriate clinical use, adoption, and payer reimbursement for assay manufacturers, as well as Clinical Laboratory Improvement Amendments-certified laboratories, including those that develop assays (laboratory developed tests). Practical criteria and steps for establishing clinical utility are crucial to subsequent decisions for reimbursement without which high-performing molecular diagnostics will have limited availability to patients with cancer and fail to translate scientific advances into high-quality and cost-effective cancer care. See all articles in this CCR Focus section, "The Precision Medicine Conundrum: Approaches to Companion Diagnostic Co-development."

Biomarker testing for breast, lung, and gastroesophageal cancers at NCI designated cancer centers

BACKGROUND

Molecular biomarkers, a cornerstone of precision oncology, are critical in breast, gastroesophageal, and non-small cell lung cancer management (BC, GEC, NSCLC). Testing practices are intensely debated, impacting diagnostic quality and affecting pathologists, oncologists and patients. However, little is known about testing approaches used in practice. Our study described biomarker practices in BC, GEC, and NSCLC at the leading US cancer centers.

METHODS

We conducted a survey of the National Cancer Institute (NCI) designated centers on BC, GEC, and NSCLC biomarker testing. We used simple frequencies to describe practices, two-sided Fisher's exact test and two-sided McNemar's test for cross-cancer comparison. All statistical tests were two-sided.

RESULTS

For BC human epidermal growth factor receptor 2 (HER2), 39% of centers combine guidelines by using in situ hybridization (ISH) and immunohistochemistry (IHC) concurrently, and 21% reflex-test beyond guideline-recommended IHC2+. For GEC HER2, 44% use ISH and IHC concurrently, and 28% reflex-test beyond IHC2+. In NSCLC, the use of IHC is limited to 4% for epidermal growth factor receptor (EGFR) and 7% for anaplastic lymphoma kinase (ALK). 43.5% test NSCLC biomarkers on oncologist order; 34.5% run all biomarkers upfront, and 22% use a sequential protocol. NSCLC external testing is statistically significantly higher than BC (P < .0001) and GEC (P < .0001). NSCLC internally developed tests are statistically significantly more common than BC (P < .0001) and GEC (P < .0001).

CONCLUSIONS

At the NCI cancer centers, biomarker testing practices vary, but exceeding guidelines is a common practice for established biomarkers and emerging practice for newer biomarkers. Use of internally developed tests declines as biomarkers mature. Implementation of multibiomarker protocols is lagging. Our study represents a step toward developing a biomarker testing practice landscape.

Accurate identification of ALK positive lung carcinoma patients: novel FDA-cleared automated fluorescence in situ hybridization scanning system and ultrasensitive immunohistochemistry

BACKGROUND

Based on the excellent results of the clinical trials with ALK-inhibitors, the importance of accurately identifying ALK positive lung cancer has never been greater. However, there are increasing number of recent publications addressing discordances between FISH and IHC. The controversy is further fuelled by the different regulatory approvals. This situation prompted us to investigate two ALK IHC antibodies (using a novel ultrasensitive detection-amplification kit) and an automated ALK FISH scanning system (FDA-cleared) in a series of non-small cell lung cancer tumor samples.

METHODS

Forty-seven ALK FISH-positive and 56 ALK FISH-negative NSCLC samples were studied. All specimens were screened for ALK expression by two IHC antibodies (clone 5A4 from Novocastra and clone D5F3 from Ventana) and for ALK rearrangement by FISH (Vysis ALK FISH break-apart kit), which was automatically captured and scored by using Bioview's automated scanning system.

RESULTS

All positive cases with the IHC antibodies were FISH-positive. There was only one IHC-negative case with both antibodies which showed a FISH-positive result. The overall sensitivity and specificity of the IHC in comparison with FISH were 98% and 100%, respectively.

CONCLUSIONS

The specificity of these ultrasensitive IHC assays may obviate the need for FISH confirmation in positive IHC cases. However, the likelihood of false negative IHC results strengthens the case for FISH testing, at least in some situations.

What do providers, payers and patients need from comparative effectiveness research on diagnostics? The case of HER2/Neu testing in breast cancer

AIMS

Comparing effectiveness of diagnostic tests is one of the highest priorities for comparative effectiveness research (CER) set by the Institute of Medicine. Our study aims to identify what information providers, payers and patients need from CER on diagnostics, and what challenges they encounter implementing comparative information on diagnostic alternatives in practice and policy.

MATERIALS & METHODS

Using qualitative research methods and the example of two alternative protocols for HER2 testing in breast cancer, we conducted interviews with 45 stakeholders: providers (n = 25) from four academic and eight nonacademic institutions, executives (n = 13) from five major US private payers and representatives (n = 7) from two breast cancer patient advocacies.

RESULTS

The need for additional scientific evidence to determine the preferred HER2 protocol was more common for advocates than payers (100 vs 54%; p = 0.0515) and significantly more common for advocates than providers (100 vs 40%; p = 0.0077). The availability of information allowing assessment of the implementation impact from alternative diagnostic protocols on provider institutions may mitigate the need for additional scientific evidence for some providers and payers (24 and 46%, respectively). The cost-effectiveness of alternative protocols from the societal perspective is important to payers and advocates (69 and 71%, respectively) but not to providers (0%; p = 0.0001 and p = 0.0001). The lack of reporting laboratory practices is a more common implementation challenge for payers and advocates (77 and 86%, respectively) than for providers (32%). The absence of any mechanism for patient involvement was recognized as a challenge by payers and advocates (69 and 100%, respectively) but not by providers (0%; p = 0.0001 and p = 0.0001).

CONCLUSION

Comparative implementation research is needed to inform the stakeholders considering diagnostic alternatives. Transparency of laboratory practices is an important factor in enabling implementation of CER on diagnostics in practice and policy. The incongruent views of providers versus patient advocates and payers on involving patients in diagnostic decisions is a concerning challenge to utilizing the results of CER.

Theranostic and molecular classification of breast cancer

CONTEXT

Despite advances in breast cancer management, women continue to relapse and die of breast cancer. Traditionally, evaluation for hormone receptors (estrogen and progesterone), as well as HER2 overexpression, have guided therapy-related decision-making because they are both prognostic and predictive indicators. However, there are limitations with those studies, which can lead to improper treatment. Gene signatures have recently been shown to be of value in identifying molecular portraits of breast carcinoma and are beginning to play role in management and treatment algorithms.

OBJECTIVE

To provide a summary of the prognostic and predictive indicators of breast cancer, such as hormone receptors, HER2, and molecular gene signatures that currently help guide clinical decision making.

DATA SOURCES

Published articles from peer-reviewed journals in PubMed (US National Library of Medicine).

CONCLUSIONS

Emerging evidence shows promise that, in addition to hormone receptors and HER2 studies, evaluating tumors with gene expression profiling can provide additional prognostic and predictive information, further aiding clinical management and leading to a more personalized approach to treating breast cancer.

Clinical implications of p57 KIP2 expression in breast cancer

OBJECTIVE

To study the relationship between expression of p57KIP2 and prognosis and other clinicopathological parameters in invasive breast cancers.

METHODS

We assessed the expression of p57KIP2 in 89 cases of invasive breast cancer and 20 cases of normal breast tissue by immunohistochemical methods and analyzed the results with SPSS software (ver. 16.0).

RESULT

The positive expression rates of p57KIP2 protein in the invasive breast cancers and surrounding normal tissue were 30.3% (27/89) and 65% (13/20), respectively. Cases with no p57KIP2 expression exhibited a significantly higher post-operative distant metastasis rate than those with p57KIP2 expression (37.9% vs. 14.8%; P = 0.01). DFS analysis showed that p57KIP2-/C-erbB-2μ tumors also exhibited a significantly higher post-operative distant metastasis rate than the other groups (66.7% vs. 29.2%; P = 0.007), as did p57KIP2-/p53μ tumors (64.3% vs. 22.7%; P = 0.001). Survival analysis revealed that p57KIP2 was associated with breast cancer-specific survival overall (P = 0.045, log-rank test). Subgroup analysis demonstrated that individuals with p57KIP2-/C-erbB-2μ tumors experienced significantly worse post-operative survival than those with p57KIP2- /C-erbB-2- or other tumors (P = 0.006, log-rank test). p57KIP2-/p53μ tumors were associated with significantly worse post-operative survival than p57KIP2-/p53- or other tumors (P = 0.001, log-rank test). Cox regression analysis showed that p57KIP2 was a non-independent prognostic factor for breast cancer (P = 0.303).

CONCLUSIONS

p57KIP2 is expressed at low levels in invasive breast cancer and is associated with better overall survival rate and disease-free survival in breast cancer patients, but it was a non-independent prognostic factor for breast cancer. Thus, the connection between p57KIP2/p53 and p57KIP2/C-erbB-2 may provide biomarkers for breast cancer.

Immunohistochemistry and fluorescence in situ hybridization assessment of HER2 in clinical trials of adjuvant therapy for breast cancer (NCCTG N9831, BCIRG 006, and BCIRG 005)

A comprehensive, blinded, pathology evaluation of HER2 testing in HER2-positive/negative breast cancers was performed among three central laboratories. Immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) analyses were performed on 389 tumor blocks from three large adjuvant trials: N9831, BCIRG-006, and BCIRG-005. In 123 cases, multiple blocks were examined. HER2 status was defined according to FDA-approved guidelines and was independently re-assessed at each site. Discordant cases were adjudicated at an on-site, face-to-face meeting. Results across three independent pathologists were concordant by IHC in 351/381 (92 %) and FISH in 343/373 (92 %) blocks. Upon adjudication, consensus was reached on 16/30 and 18/30 of discordant IHC and FISH cases, respectively, resulting in overall concordance rates of 96 and 97 %. Among 155 HER2-negative blocks, HER2 status was confirmed in 153 (99 %). In the subset of 102 HER2-positive patients from N9831/BCIRG-006, primary blocks from discordant cases were selected, especially those with discordant test between local and central laboratories. HER2 status was confirmed in 73 (72 %) of these cases. Among 118 and 113 cases with IHC and FISH results and >1 block evaluable, block-to-block variability/heterogeneity in HER2 results was seen in 10 and 5 %, respectively. IHC−/FISH− was confirmed for 57/59 (97 %) primary blocks from N9831 (locally positive, but centrally negative); however, 5/22 (23 %) secondary blocks showed HER2 positivity. Among 53 N9831 patients with HER2-normal disease adjudicated as IHC−/FISH—(although locally positive), there was a non-statistically significant improvement in disease-free survival with concurrent trastuzumab compared to chemotherapy alone (adjusted hazard ratio 0.34; 95 % CI, 0.11–1.05; p = 0.06). There were similar agreements for IHC and FISH among pathologists (92 % each). Agreement was improved at adjudication (96 %). HER2 tumor heterogeneity appears to partially explain discordant results in cases initially tested as positive and subsequently called negative.

HER2 Status by Standardized Immunohistochemistry and Silver-Enhanced In Situ Hybridization in Korean Breast Cancer

PURPOSE

Amplification of the human epidermal growth factor receptor 2 (HER2) gene occurs in 18% to 20% of breast cancers, and it is recognized as a prognostic and predictive marker. We investigated the HER2 status in Korean breast cancer by immunohistochemistry (IHC) and silver-enhanced in situ hybridization (SISH), as the first step toward building a nationwide quality assurance program for HER2 testing.

METHODS

A total of 1,198 breast carcinoma samples were collected from six institutions and IHC and SISH were performed using tissue microarrays in central laboratories. The results were compared to those of local laboratories.

RESULTS

Available data were obtained from 959 samples. Central IHC results were negative, equivocal, and positive for 756 (78.8%; range among institutions, 76.8-81.8%), 37 (3.9%; 1.9-6.2%), and 166 (17.3%; 13.6-20%), respectively. SISH results were negative, equivocal, and positive for 756 (78.8%; 77.4-79.9%), 2 (0.2%; 0-0.7%), and 201 (21%; 20.1-22.2%), respectively. HER2 gene amplification was observed in 4.4%, 19%, and 73.9% of the negative, equivocal and positive groups stratified by local IHC results, respectively. When central SISH was considered to be the gold standard method for measuring HER2 status, the false-negative and false-positive rates of local IHC were 14.4% (29/201) and 7.1% (54/756). The concordance rate between central IHC and SISH was 98.4%.

CONCLUSION

Central IHC and SISH markedly decreased the interlaboratory variability of HER2 status and the results of the two were highly concordant. The quality control program for HER2 testing must be focused on decreasing both the false negativity and positivity of IHC in local laboratories.

HER2 and TOP2A in high-risk early breast cancer patients treated with adjuvant epirubicin-based dose-dense sequential chemotherapy

Background

HER2 and TOP2A parameters (gene status, mRNA and protein expression) have individually been associated with the outcome of patients treated with anthracyclines. The aim of this study was to comprehensively evaluate the prognostic/predictive significance of the above parameters in early, high-risk breast cancer patients treated with epirubicin-based, dose-dense sequential adjuvant chemotherapy.

Methods

In a series of 352 breast carcinoma tissues from patients that had been post-operatively treated with epirubicin-CMF with or without paclitaxel, we assessed HER2 and TOP2A gene status (chromogenic in situ hybridization), mRNA expression (quantitative reverse transcription PCR), as well as HER2 and TopoIIa protein expression (immunohistochemistry).

Results

HER2 and TOP2A amplification did not share the same effects on their downstream molecules, with consistent patterns observed in HER2 mRNA and protein expression according to HER2 amplification (all parameters strongly inter-related, p values < 0.001), but inconsistent patterns in the case of TOP2A. TOP2A gene amplification (7% of all cases) was not related to TOP2A mRNA and TopoIIa protein expression, while TOP2A mRNA and TopoIIa protein were strongly related to each other (p < 0.001). Hence, TOP2A amplified tumors did not correspond to tumors with high TOP2A mRNA or TopoIIa protein expression, while the latter were characterized by high Ki67 scores (p = 0.003 and p < 0.001, respectively). Multivariate analysis adjusted for nodal involvement, hormone receptor status, Ki67 score and HER2/TOP2A parameters revealed HER2/TOP2A co-amplification (21.2% of HER2 amplified tumors) as an independent favorable prognostic factor for DFS (HR = 0.13, 95% CI: 0.02-0.96, p = 0.046); in contrast, increased HER2/TOP2A mRNA co-expression was identified as an independent adverse prognostic factor for both DFS (HR = 2.41, 95% CI: 1.31-4.42, p = 0.005) and OS (HR = 2.83, 95% CI: 1.42-5.63, p = 0.003), while high TOP2A mRNA expression was an independent adverse prognostic factor for OS (HR = 2.06, 95% CI: 1.23-3.46, p = 0.006). None of the parameters tested was associated with response to paclitaxel.

Conclusions

This study confirms the favorable prognostic value of HER2/TOP2A co-amplification and the adverse prognostic value of high TOP2A mRNA expression extending it to the adjuvant treatment setting in early high-risk breast cancer. The strong adverse prognostic impact of high HER2/TOP2A mRNA co-expression needs further validation in studies designed to evaluate markers predictive for anthracyclines.

Trial registration

Australian New Zealand Clinical Trials Registry ACTRN12611000506998.

Girdin protein: a new potential distant metastasis predictor of breast cancer

To investigate the expression status and the clinical implications of Girdin protein in breast cancer. The expression status of Girdin protein and clinicopathological parameters in 820 breast cancer specimens was analyzed using immunohistochemistry staining and the relationship between Girdin protein and clinicopathological parameters. The prognosis of breast cancer was subsequently determined. Girdin protein was expressed positively in 295 (35.98%) of the 820 cases examined. The expression of Girdin protein was related to histological type and CerbB2 (P = 0.001, 0.006, and 0.001, respectively). After analyzing survival rates, the cases with highly expressed Girdin protein were shown to attain a significantly more distant metastasis rate and poorer postoperative, disease-specific survival than those with none or low expressed Girdin protein (P = 0.001). In the Cox regression test, Girdin protein was detected as an independent prognostic factor (P = 0.031). Girdin protein may be a potential new distant metastasis biomarker of breast cancer.

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.

Female breast cancer status according to ER, PR and HER2 expression: a population based analysis

The aim of this study is to evaluate the prognostic values of some biological parameters in a population based series of female breast cancer patients. Through the Tuscan Cancer Registry all the invasive breast cancer cases diagnosed during the period 2004-2005 in the provinces of Florence and Prato, central Italy, were retrieved. Molecular subtypes were analyzed defined by immunohistochemical markers, by age, tumor size, lymph node status, histotype, grade of differentiation and proliferative marker. Out of 1487 patients 70.3% were luminal A subtype (ER/PR + HER2-), 15.6% luminal B (ER/PR + HER2+), 8.1% triple negative (ER/PR-HER2-), 6.0% HER2+ (ER/PR-HER2+); the 3 year survival rates were 93.3%, 89.5%, 86.3%, 82.7% respectively (p < 0.001). Analysis of survival by the Cox proportional hazards model showed an independent prognostic value of molecular classification. Our study revealed significant differences in clinicopathological characteristics among breast cancer molecular subtypes and confirmed their prognostic independent role.