scholarly journals Single HER2-positive tumor cells are detected in initially HER2-negative breast carcinomas using the DEPArray™–HER2-FISH workflow

Breast Cancer ◽  
2022 ◽  
Author(s):  
Lisa Grüntkemeier ◽  
Aditi Khurana ◽  
Farideh Zamaniyan Bischoff ◽  
Oliver Hoffmann ◽  
Rainer Kimmig ◽  
...  
Keyword(s):  
Tumor Cells ◽  
Validation Cohort ◽  
Single Cells ◽  
Chromosome 17 ◽  
Antigen Retrieval ◽  
Her2 Status ◽  
Fish Analysis ◽  
Cell Recovery ◽  
Her2 Positive ◽  
Ffpe Tumor

Abstract Background In breast cancer (BC), overexpression of HER2 on the primary tumor (PT) is determined by immunohistochemistry (IHC) or fluorescence in situ hybridization (FISH) to stratify samples as negative, equivocal and positive to identify patients (pts) for anti-HER2 therapy. CAP/ASCO guidelines recommend FISH for analyzing HER2/neu (ERBB2) gene amplification and for resolving equivocal HER2 IHC results. However, pre-analytical and analytical aspects are often confounded by sample related limitations and tumor heterogeneity and HER2 expression may differ between the PT and circulating tumor cells (CTCs), the precursors of metastasis. We used a validation cohort of BC patients to establish a new DEPArray™-PT-HER2-FISH workflow for further application in a development cohort, characterized as PT-HER2-negative but CTC-HER2/neu-positive, to identify patients with PT-HER2 amplified cells not detected by routine pathology. Methods 50 µm FFPE tumor curls from the validation cohort (n = 49) and the development cohort (n = 25) underwent cutting, deparaffinization and antigen retrieval followed by dissociation into a single-cell suspension. After staining for cytokeratin, vimentin, DAPI and separation via DEPArray™, single cells were processed for HER2-FISH analysis to assess the number of chromosome 17 and HER2 loci signals for comparison, either with available IHC or conventional tissue section FISH. CTC-HER2/neu status was determined using the AdnaTest BreastCancer (QIAGEN, Hilden, Germany). Results Applying CAP/ASCO guidelines for HER2 evaluation of single PT cells, the comparison of routine pathology and DEPArray™-HER2-FISH analysis resulted in a concordance rate of 81.6% (40/49 pts) in the validation cohort and 84% (21/25 pts) in the development cohort, respectively. In the latter one, 4/25 patients had single HER2-positive tumor cells with 2/25 BC patients proven to be HER2-positive, despite being HER2-negative in routine pathology. The two other patients showed an equivocal HER2 status in the DEPArray™-HER2-FISH workflow but a negative result in routine pathology. Whereas all four patients with discordant HER2 results had already died, 17/21 patients with concordant HER2 results are still alive. Conclusions The DEPArray™ system allows pure tumor cell recovery for subsequent HER2/neu FISH analysis and is highly concordant with conventional pathology. For PT-HER2-negative patients, harboring HER2/neu-positive CTCs, this approach might allow caregivers to more effectively offer anti-HER2 treatment.

CLIA validation of a novel HER2 FISH test involving image-based cell-sorting to recover pure tumor cell populations from formalin fixed paraffin embedded tissue.

2017 ◽  
Vol 35 (15_suppl) ◽  
pp. e12519-e12519
Author(s):  
Farideh Z. Bischoff ◽  
Amanda Gerber ◽  
Valeria Sero ◽  
Aditi Khurana ◽  
Marc Ting ◽  
...  
Keyword(s):  
Tumor Cell ◽  
Tumor Cells ◽  
Single Cells ◽  
Chromosome 17 ◽  
Her2 Status ◽  
Cell Populations ◽  
Molecular Testing ◽  
Fish Analysis ◽  
Tumor Type ◽  
Her2 Positive

e12519 Background: The use of the DEPArray™ system to prepare pure tumor cell populations for more reliable and accurate downstream molecular sequence analysis has been previously demonstrated. To formally evaluate the utility of the DEPArray™ for sample preparation prior to molecular testing, we conducted a CLIA validation study to investigate the analytical performance of the instrument as well as accuracy in determining HER2 status in FFPE tumor specimens using a standard FISH assay. Methods: An initial cohort consisting of 93 FFPE samples (68 from Breast and 25 from Stomach) were selected based on defined inclusion criteria (tumor type and tumor content). For each sample, a single 50µm FFPE scroll was dissociated and then stained using fluorescently labeled Vimentin and Cytokeratin markers to distinguish between putative stromal and tumor populations, respectively. Following separation of these populations on the DEPArray™, a minimum of 100 single cells from each population was recovered and used for subsequent HER2 FISH testing. In addition, an H&E of each sample was evaluated by a Pathologist to confirm the presence of tumor content. Single-cell HER2-FISH analysis was then performed on the DEPArray™ processed samples to assess the number of signals present for each of the chromosome 17 and HER2 loci. Results were compared to the conventional tissue section FISH score. Results: Of the 93 specimens, 80 samples met pre-analytical acceptability criteria that were also confirmed by conventional methods to be either HER2-positive (n = 43) or HER2-negative (n = 37). Overall, a 95% concordance between HER2 results derived from the conventional as compared to the DEPArray™ method was observed. In addition, the instrument performance in terms of reproducibility and reliability was reported as 100%. Conclusions: DEPArray™ for preparation of FFPE-derived tumor cells was analytically validated and shown to yield high confidence in performing HER2-FISH analysis on recovered pure tumor cells. Current strategies to establish clinical utility and efficacy of this approach are underway for cases characterized as equivocal for HER2 or indeterminate by FISH.

Inter-laboratory evaluation of a novel DEPArray-HER2 FISH assay.

2017 ◽  
Vol 35 (15_suppl) ◽  
pp. e12506-e12506
Author(s):  
Amanda Gerber ◽  
Lisa Koenig ◽  
Lori Millner ◽  
Lindsay Strotman ◽  
Valeria Sero ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Tumor Cells ◽  
Treatment Options ◽  
Positive Control ◽  
Laboratory Evaluation ◽  
Her2 Status ◽  
Tumor Biomarker ◽  
Fish Analysis ◽  
Her2 Gene ◽  
Her2 Positive

e12506 Background: Fluorescent in Situ Hybridization (FISH) is a method currently used for detection and assessment of HER2 gene amplification. Although clinical guidelines set forth by CAP/ASCO exist to ensure accuracy, limitations in HER2test results due to sample preparation, assay-conditions and tumor heterogeneity remain unresolved. We have successfully demonstrated analytical confidence in performing HER2 FISH on DEPArray™ sorted and recovered tumor cells. In this study, we aimed to evaluate inter-laboratory concordance of the DEPArray™ HER2-FISH assay. Methods: Three laboratories equipped with the DEPArray™ were designated as testing sites for this study. Positive control SKBr3 cells embedded in paraffin as well as 20 invasive breast carcinoma FFPE samples were blinded and evaluated by each of the three labs. Control and patient samples were processed through the DEPArray™ beginning with dissociation of the FFPE curls followed by single-cell image-based cell sorting to separate and recover pure distinct tumor cell populations prior to HER2 FISH analysis. Data was only obtained when ∼200 intact cytokeratin+/vimentin-/DAPI+ tumor cells from each sample were recovered and used for subsequent FISH using a standard dual-color HER2/CEP17 FISH procedure. Results: Overall, 80% concordance between DEPArray™-HER2 and conventional HER2 (6 HER2 negative and 10 HER2 positive) was observed between lab(s) and the conventional HER2 method. In each of 4 cases, a discordant HER2 result was reported by one of three sites. In three of these discordant cases, the DEPArray™ HER2 ratio was reported as amplified while the conventional result was negative. In the remaining discordant case, the converse was observed by one site; however, this case was initially evaluated 15 years ago. All three sites correctly scored the SKBr3 positive control cells. Conclusions: The results showed a high concordance rate of correct HER2 status classification. This data further supports the understanding that tissue heterogeneity can indeed give rise to discordant results that may consequently affect treatment options for patients. We demonstrate that sample preparation by DEPArray™ may aid in a more precise classification for tumor biomarker status.

Central review of discordant samples for microarray-based ER, PR, and HER2 and local IHC/FISH assessment worldwide from 827 patients.

2012 ◽  
Vol 30 (27_suppl) ◽  
pp. 11-11
Author(s):  
Jelle Wesseling ◽  
Corrado Tinterri ◽  
Anna Sapino ◽  
Fabrizio Zanconati ◽  
Martijn Lutke Holzik ◽  
...  
Keyword(s):  
Gene Expression ◽  
Her2 Status ◽  
Fish Analysis ◽  
Mrna Expression Level ◽  
Her2 Expression ◽  
Her2 Positive ◽  
High Quality ◽  
Standard Procedures ◽  
Local Standard ◽  
Er Positive

11 Background: Differences in fixation and IHC and subjective interpretation can substantially affect the accuracy and reproducibility of estrogen receptor (ER), progesterone receptor (PR) and HER2 expression. The commercially available TargetPrint test measures the mRNA expression level of ER, PR and HER2 and is 98% concordant with centrally assessed ER as presented by Viale et al, SABCS 2011. This study compares results from the microarray-based TargetPrint with IHC and FISH (for HER2 IHC2+) generated by local standard procedures. Methods: Fresh tumor samples (core needle biopsies or surgical) were collected for 831 patients diagnosed with breast cancer stage I to IV (Feb 2008 - Jan 2011) from 22 hospitals from Europe, New Zealand, Japan and US. The results of the IHC/FISH assessments performed according to the local standards at the hospitals were compared to the quantitative gene expression readouts with TargetPrint. Discordant cases were centrally reviewed for IHC/FISH assessment. Results: Of the 831 samples, IHC assessment was unknown for 4 ER/ PR samples; HER2 was unknown for 12 samples. Comparison of IHC and gene expression read out by TargetPrint showed a concordance of 95% for ER; 83% for PR and 94% for HER2. In this study, 3% of all IHC ER positive samples were classified negative by microarray, and 11% of IHC PR positive samples were classified negative by microarray. For HER2, 4% of IHC/FISH HER2 positive samples were classified negative by microarray and 2% of IHC/FISH HER2 negative samples were classified positive by microarray. Most notably, all available 5 ER IHC negative/TargetPrint positive samples turned out to be positive with central re-assessment. HER2 IHC2+ samples with discordant classifications for TargetPrint and local assessment are currently being reviewed for FISH/SISH assessment. Conclusions: Microarray based readout of ER, PR and HER2 status using TargetPrint is fairly comparable to local IHC and FISH analysis in 827 analyzed samples in various hospitals worldwide. However, re-assessment of discordant cases–especially IHC ER-/TargetPrint ER+ cases- confirms TargetPrint to be a useful high quality second opinion for local IHC/FISH assessment.

Persistence of HER2 overexpression on circulating tumor cells in patients after systemic treatment for HER2-positive breast cancer: Follow-up results of the German Success B trial.

2013 ◽  
Vol 31 (15_suppl) ◽  
pp. 11043-11043 ◽  
Author(s):  
Julia Katharina Neugebauer ◽  
Brigitte Kathrin Rack ◽  
Bernadette Anna Sophia Jaeger ◽  
Ulrich Andergassen ◽  
Aurelia Pestka ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Tumor Cells ◽  
Circulating Tumor Cells ◽  
Peripheral Blood ◽  
Her2 Status ◽  
Her2 Overexpression ◽  
Her2 Expression ◽  
Her2 Positive ◽  
Before And After

11043 Background: The discordance between HER2-expression on circulating tumor cells (CTC) in peripheral blood and the primary tumor has already been shown by our study group for early breast cancer patients with HER2-positive tumors. Here, we compare the results to CTC prevalence and HER2-status of CTC after adjuvant chemotherapy. Methods: The SUCCESS B trial compares FEC-Docetaxel vs. FEC-Docetaxel-Gemcitabine and HER2-targeted therapy as adjuvant treatment for patients with early, HER2-positive, node positive or high risk node negative primary breast cancer. We prospectively analyzed 23ml peripheral blood before and after chemotherapy. CTC and HER2-status were assessed with the CellSearchSystem (Veridex, USA). After immunomagnetic enrichment with an anti-Epcam-antibody, cells were labeled with anti-CK 8/18/19, anti-CD45 antibodies as well as a fluorescein conjugate antibody for HER2-phenotyping. Cutoff for CTC positivity was ≥ 1 CTC. HER-positivity of CTC was assigned if at least one CTC showed strong HER2 staining (3+). Results: CTCs and their HER2-status both before and after chemotherapy were available for 392 patients. In 179 (45.7%) patients no CTC were detected before and after chemotherapy. CTC status changed from positive before to negative after chemotherapy in 104 (26.5%) patients and from negative before to positive after chemotherapy in 69 (17.6%) patients, while 40 (10.2%) patients had a consistently positive CTC status. Patients were significantly more likely to change their CTC status from positive to negative than from negative to positive (p = 0.01). Of the 40 patients with CTC both before and after chemotherapy, 14 (35%) patients had HER2-positive CTC before and after therapy, and 9 (22%) patients had HER2-negative CTC at both time points. 7 (18%) patients had HER2-positive CTC before but not after chemotherapy, while 10 (25%) patients showed the reverse pattern (p = 0.63). Conclusions: Cytotoxic treatment does not seem to influence the HER2-status on CTC. Follow-up data within the Success B trial will analyze the relevance of the HER2-expression of CTC to predict the efficacy of targeted treatment.

Quantification of intratumoral heterogeneity of HER2 status in breast cancer.

2017 ◽  
Vol 35 (15_suppl) ◽  
pp. 1036-1036
Author(s):  
Rie Horii ◽  
Masaaki Matsuura ◽  
Hiro Nitta ◽  
Yoshinori Ito ◽  
Shinji Ohno ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Tumor Cells ◽  
Intratumoral Heterogeneity ◽  
Gene Copy ◽  
Her2 Status ◽  
Her2 Gene ◽  
Her2 Positive ◽  
Her2 Positive Breast Cancer ◽  
Protein Status ◽  
Positive Breast Cancer

1036 Background: Intratumoral heterogeneity (ITH) occurs as a consequence of epigenetic aberrations in tumor cells with genetic diversity. HER2 ITH can be classified into genetic (a mixture of tumor cells with and without HER2 gene amplification) and epigenetic ITH (a mixture of HER2 gene-amplified tumor cells with and without HER2 protein overexpression). However, the both effects of genetic and epigenetic ITH on HER2-targeted therapy have not been clearly demonstrated. In order to implement ITH as a referenced factor for treatment selection, the ITH quantification is necessary. Gene-protein assay (GPA), in which immunohistochemistry and dual in situ hybridization are simultaneously performed on a single slide, allows bright-field analyses of both gene and protein status. We aimed to quantify HER2 ITH by the combination of gene and protein status and clarify its clinical significance. Methods: Fifty three patients with HER2-positive breast cancer, who underwent neoadjuvant trastuzumab with chemotherapy, were examined. Five representative microscopic images were captured from a GPA slide of a pre-therapeutic biopsy material. All evaluable tumor cells in the images were scored according to the HER2 status determined by the combination of gene copy number and protein expression (Table). We investigated the relationship between the HER2 scores and pathological complete response (pCR) to the neoadjuvant treatment by the logistic analysis. Results: The average of HER2 scores, indicating the degree of the HER2 status, varied from 2.21 to 5.98. It was significantly related to pCR (Estimate: 1.21, Std. error: 0.46, RR: 3.34, P=0.009, 95%CI: 1.35-8.25). The standard deviation of HER2 scores, indicating the degree of the HER2 ITH, varied from 0.13 to 1.37. It was significantly related to pCR (Estimate: -2.09, Std. error: 0.83, RR: 0.12, P=0.012, 95%CI: 0.02-0.63). Conclusions: HER2 ITH, quantified by GPA, is a predictive factor for the therapeutic effect to trastuzumab-based treatment in HER2-positive breast cancer. [Table: see text]

scholarly journals Outcome of HER2 Testing by FISH applying ASCO/CAP 2007 and 2013 guideline in IHC equivocal group of breast cancer: Experience at tertiary cancer care centre

2017 ◽  
Vol 06 (02) ◽  
pp. 045-046
Author(s):  
Manoj Kumar Panigrahi ◽  
Dushyant Kumar ◽  
Anurag Mehta ◽  
Kandarpa Kumar Saikia
Keyword(s):  
Breast Cancer ◽  
Final Analysis ◽  
Chromosome 17 ◽  
Research Centre ◽  
Her2 Status ◽  
Her2 Positive ◽  
Her2 Testing ◽  
Polysomy 17 ◽  
Cancer Experience ◽  
The Impact

Abstract Background and Objectives: HER2 testing guideline of ASCO/CAP for interpretation and reporting has recently been revised. The study is aimed to measure the impact of 2013 CAP guideline on equivocal HER2 test outcome (immunohistochemistry [IHC] 2+) when tested by fluorescent in situ hybridization (FISH). The study also aims at finding the frequency of polysomy and monosomy of chromosome 17. Materials and Methods: Specimens were collected in Rajiv Gandhi Cancer Institute and Research Centre, New Delhi, India. IHC was performed in every case, and FISH was performed in IHC2+ cases. Results: In final analysis includes 557 subjects on the basis of CAP guideline 2007 and CAP guideline 2013. One hundred ninety-two subjects (34.4%) were HER2 amplified according to CAP scoring 2007, and 246 subjects (44%) according to 2013 CAP scoring. Conclusions: FISH results were evaluated (IHC2 + interpreted according to CAP 2007 guideline) with both 2007 and 2013 ASCO/CAP scoring criteria, we identified significantly more HER2 positive cases as compared to cases evaluated using the 2007 criteria (P < 0.05). We also found that in breast carcinoma, HER2 status in the presence of polysomy 17 may vary with the scoring criteria used. Evaluation of FISH result using 2013 ASCO/CAP criteria means that more patients with breast cancer may be appropriate for targeted treatment with trastuzumab, potentially improving their outcome.

Central review of discordant samples for microarray based on ER, PR, and HER2 and local IHC/FISH assessment worldwide from 827 patients.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. 10554-10554
Author(s):  
Jelle Wesseling ◽  
Corrado Tinterri ◽  
Anna Sapino ◽  
Fabrizio Zanconati ◽  
Martijn Lutke Holzik ◽  
...  
Keyword(s):  
Gene Expression ◽  
Her2 Status ◽  
Fish Analysis ◽  
Mrna Expression Level ◽  
Her2 Expression ◽  
Her2 Positive ◽  
High Quality ◽  
Standard Procedures ◽  
Local Standard ◽  
Er Positive

10554 Background: Differences in fixation and IHC and subjective interpretation can substantially affect the accuracy and reproducibility of estrogen receptor (ER), progesterone receptor (PR) and HER2 expression. The commercially available TargetPrint test measures the mRNA expression level of ER, PR and HER2 and is 98% concordant with centrally assessed ER as presented by Viale et al, SABCS 2011. This study compares results from the microarray-based TargetPrint with IHC and FISH (for HER2 IHC2+) generated by local standard procedures. Methods: Fresh tumor samples (core needle biopsies or surgical) were collected for 831 patients diagnosed with breast cancer stage I to IV (Feb 2008 - Jan 2011) from 22 hospitals from Europe, New Zealand, Japan and US. The results of the IHC/FISH assessments performed according to the local standards at the hospitals were compared to the quantitative gene expression readouts with TargetPrint. Discordant cases were centrally reviewed for IHC/FISH assessment. Results: Of the 831 samples, IHC assessment was unknown for 4 ER/ PR samples; HER2 was unknown for 12 samples. Comparison of IHC and gene expression read out by TargetPrint showed a concordance of 95% for ER; 83% for PR and 94% for HER2. In this study, 3% of all IHC ER positive samples were classified negative by microarray, and 11% of IHC PR positive samples were classified negative by microarray. For HER2, 4% of IHC/FISH HER2 positive samples were classified negative by microarray and 2% of IHC/FISH HER2 negative samples were classified positive by microarray. Most notably, all available 5 ER IHC negative/TargetPrint positive samples turned out to be positive with central re-assessment. HER2 IHC2+ samples with discordant classifications for TargetPrint and local assessment are currently being reviewed for FISH/SISH assessment. Conclusions: Microarray based readout of ER, PR and HER2 status using TargetPrint is fairly comparable to local IHC and FISH analysis in 827 analyzed samples in various hospitals worldwide. However, re-assessment of discordant cases –especially IHC ER-/TargetPrint ER+ cases- confirms TargetPrint to be a useful high quality second opinion for local IHC/FISH assessment.

Profiling of circulating tumor cells isolated from 105 metastatic gastric cancer patients revealed HER2 overexpression/activation for potential use in clinical setting.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. 10535-10535 ◽  
Author(s):  
Saswati Hazra ◽  
Jeeyun Lee ◽  
Phillip Sangwook Kim ◽  
Kyoung-Mee Kim ◽  
Limin Liu ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Tumor Cells ◽  
Circulating Tumor Cells ◽  
Predictive Marker ◽  
Patient Treatment ◽  
Her2 Status ◽  
Her2 Overexpression ◽  
Her2 Expression ◽  
Her2 Positive ◽  
Over Expression

10535 Background: Gastric cancer (GCA) is the second leading cause of cancer mortality in the world. Survival of patients with advanced GCA treated with chemotherapy remains low. New targeted therapies are urgently needed. There is mounting evidence of the role of HER2 overexpression in patients with GCA, and it has been highly correlated to poor outcomes with more aggressive disease. The ability to accurately determine HER2 status by testing circulating tumor cells (CTCs) may improve patient treatment by allowing ongoing assessment of HER2 status during treatment and/or identifying additional patients who could potentially benefit from HER2- targeted therapy. Methods: The Collaborative Enzyme Enhanced Reactive-immunoassay (CEER) was utilized to determine the expression and activation (phosphorylation) levels of HER2 in CTCs isolated from blood specimens obtained from 105 metastatic GCA patients. Results: Utilizing the CEER platform, the levels of HER2 expression and phosphorylation were determined for CTCs isolated from metastatic GCA patients. Evaluable CTCs were found in 33% (35/105) of enrolled patients. Out of 35 patients, 7 patients (20%) have high HER2 over expression, 6 patients (17%) have moderate HER2 expression and 11 patients (31%) have HER2 activation (phospho positive) with no HER2 over-expression. Conclusions: When CTCs were present, the CEER assay identified varying levels of HER2 involvements in 68% of metastatic GCA patients. HER2 positive CTCs could serve as a prognostic and/or predictive marker in patients with advanced GCA and CTC-HER2 profile shifts can be utilized to monitor the treatment efficacy.

scholarly journals Clinical Overestimation of HER2 Positivity in Early Estrogen and Progesterone Receptor–Positive Breast Cancer and the Value of Molecular Subtyping Using BluePrint

2017 ◽  
Vol 3 (4) ◽  
pp. 314-322 ◽  
Author(s):  
Ettienne J. Myburgh ◽  
Lizanne Langenhoven ◽  
Kathleen A. Grant ◽  
Lize van der Merwe ◽  
Maritha J. Kotze
Keyword(s):  
Breast Cancer ◽  
Progesterone Receptor ◽  
Molecular Subtype ◽  
Chromosome 17 ◽  
Her2 Status ◽  
Luminal A ◽  
Her2 Positive ◽  
Molecular Subtyping ◽  
Predictive Values ◽  
Her2 Positivity

Purpose Human epidermal growth factor receptor 2 (HER2) positivity is an important prognostic and predictive indicator in breast cancer. HER2 status is determined by immunohistochemistry and fluorescent in situ hybridization (FISH), which are potentially inaccurate techniques as a result of several technical factors, polysomy of chromosome 17, and amplification or overexpression of CEP17 (centromeric probe for chromosome 17) and/or HER2. In South Africa, HER2-positive tumors are excluded from a MammaPrint (MP; Agendia BV, Amsterdam, Netherlands) pretest algorithm. Clinical HER2 status has been reported to correlate poorly with molecular subtype. The aim of this study was to investigate the correlation of clinical HER2 status with BluePrint (BP) molecular subtyping. Methods Clinico-pathologic and genomic information was extracted from a prospectively collected central MP database containing records of 256 estrogen receptor–positive and/or progesterone receptor–positive tumors. Twenty-one tumors considered HER2 positive on immunohistochemistry or FISH were identified for this study. Results The median age of patients was 56 years (range, 34 to 77 years), with a median tumor size of 16 mm (3 to 27 mm). Four (19%) tumors were confirmed HER2-enriched subtype, six (29%) were luminal A, and 11 (52%) were luminal B. The positive predictive values of HER2/CEP17 ratio ≥ 2 and HER2 copy number ≥ 6 were only 29% and 40%, respectively. The differences in means for HER2/CEP17 ratio were significant between BP HER2-enriched versus luminal ( P = .0249; 95% CI, 0.12 to 1.21) and MP high-risk versus low-risk tumors ( P = .0002; 95% CI, 0.40 to 1.06). Conclusion Of the 21 tumors considered clinically HER2 positive, only four were HER2-enriched subtype with BP, indicating an overestimation of HER2 positivity. FISH testing has a poor positive predictive value.

scholarly journals Double-Equivocal HER2 Invasive Breast Carcinomas: Institutional Experience and Review of Literature

2018 ◽  
Vol 142 (12) ◽  
pp. 1511-1516 ◽  
Author(s):  
Brannan B. Griffin ◽  
Jennifer L. Pincus ◽  
Kalliopi P. Siziopikou ◽  
Luis Z. Blanco
Keyword(s):  
Chromosome 17 ◽  
Her2 Status ◽  
Breast Carcinomas ◽  
Her2 Positive ◽  
Close Proximity ◽  
Reference Probe ◽  
Institutional Experience ◽  
Reflex Testing ◽  
Invasive Breast Carcinomas ◽  
American Society

Context.— HER2 status is a prognostic factor and therapeutic target in invasive breast carcinomas. Reflex testing using an alternate method is recommended on equivocal cases via immunohistochemistry or fluorescence in situ hybridization (FISH). Therapeutic dilemmas arise when both tests are equivocal. The standard chromosome 17 centromere reference probe (CEP17) is in close proximity to the HER2 locus and may be coamplified, leading to equivocal results. Alternate chromosome 17 reference probes may aid in establishing the true HER2 status. Objective.— To describe our institutional experience using D17S122 probe for reflex FISH testing on double-equivocal invasive breast carcinomas and review the literature on alternate reference probes. Data Sources.— Twenty-two patients with double-equivocal invasive breast carcinomas, defined as HER2 immunohistochemistry score 2+ and FISH equivocal per the 2013 guidelines, were reviewed. Reflex FISH was performed with alternate probe D17S122 and the HER2 status classified for 11 cases by using a revised HER2:D17S122 ratio. Seven of 11 cases (63.6%) were ultimately classified as HER2 positive, while 4 cases (36.4%) remained equivocal. The 7 positive cases showed a HER2:D17S122 greater than 2.0. Conclusions.— Alternate probe D17S122 reclassified more than half of our cases as HER2 positive. Alternate probes may establish true HER2 status and direct proper management, as evidenced by our experience and the literature. Additional investigation is needed to determine which alternate probe(s) is(are) best for reflex testing. Finally, the American Society of Clinical Oncology/College of American Pathologists guidelines may need to be updated to reflect more specific recommendations for the utilization of appropriate probes in double-equivocal HER2 cases.

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