Tissue HER2 Status Research Articles

The prognostic significance of circulating tumor cell enumeration and HER2 expression by a novel automated microfluidic system in metastatic breast cancer

BackgroundThe prognostic value of circulating tumor cells (CTCs) in metastatic breast cancer (MBC) has been extensively studied and verified by the CellSearch® system. Varieties of microfluidic systems have been developed to improve capture efficiency with the lack of standardization and automation. This study systematically verified the positive threshold for prognosis and its guidance value in anti-HER2 therapy based on a novel automated microfluidic system OmiCell®.MethodsCTCs isolation, enumeration and labeling were performed using the OmiCell® system. CTCs identification and reporting were performed using the DeepSight® scanning system.ResultsThe capture efficiency and specificity of OmiCell® system was 91.9% and 90%, respectively. Then, 65 MBC patients with known HER2 status of their metastatic tumors were enrolled. In the cohort, we detected ≥ 1 CTCs in 59 patients (90.8%, range: 1–55 CTCs, median = 6), < 8 CTCs in 45 (69.2%) and ≥ 8 CTCs in 20 (30.8%) patients at baseline. The patients with < 8 CTCs had longer PFS than ≥ 8 CTCs (median, 7 vs. 4.4 months, p = 0.028). CTC enumeration was found to be an independent prognostic factor in our cohort. Moreover, we found a weak concordance between tissue HER2 (tHER2) status and the corresponding CTCs (k = 0.16, p = 0.266). The patients with tHER2 positive and cHER2 negative had better PFS compared with patients with both tHER2 and cHER2 positive (median, 8.2 vs. 3.3 months, p = 0.022).ConclusionsThis clinical study shows the prognosis value of a new threshold of CTC number and meanwhile the guidance value of cHER2 status in anti-HER2 therapy.

Study the technical validity and feasibility of serum HER-2/Neu and its correlation with tissue HER-2 status in female breast cancer patients only

Background: Breast cancer is one of the leading causes of death in women worldwide. The future burden of breast cancer is predicted to increase over 3 million new cases and 1 million deaths in 2040. In India, it is being increasingly diagnosed at a younger age as compared to the west. Human epidermal growth factor receptor 2 (HER-2) transmembrane protein, with a molecular weight 185 kDa, plays a key role in cell growth and its overexpression favors cell proliferation by inhibiting apoptosis. HER-2 extracellular domain, released into blood before appearing into tissue, can be easily detected by enzyme-linked immunosorbent assay (ELISA) using serum. HER-2 has many roles in assisting diagnosis, targeted therapy, and evaluating prognosis. Aims and Objectives: The study aimed to monitor the serum HER-2 level and its correlation with tissue HER-2 status in breast cancer patients. Materials and Methods: We performed a prospective study on technical validity and feasibility of serum HER-2 level by ELISA in breast cancer patients and its correlation with tissue HER-2 status by immunohistochemistry (IHC) method. Results: We found the serum ELISA level was raised and within the reference range in all breast cancer patients. A higher level of serum HER-2 level was seen in high tumor stage, high Nottingham grade, and with axillary lymph node metastasis. Serum HER-2 level was significantly higher in IHC score 3+ as compared to score 2+and 1+. Conclusion: This study concluded that serum HER-2 ELISA is a valid and feasible test. Association of serum HER-2 level with tumor stage; Nottingham grade; and axillary nodal metastasis was significant. The correlation between serum HER-2 and tissue HER-2 was found significant. Thus, serum HER-2 may be used as an early diagnostic and prognostic biomarker to guide in clinical practice.

HER2 Status in RAS and BRAF Wild-Type Metastatic Colorectal Cancer: A Portuguese Study.

Colorectal cancer (CRC) is the second-most deadly cancer worldwide. However, there remains a scarcity of precision treatmentsavailable for this type of cancer. Amplification or overexpression of human epidermal growth factor receptor 2 (HER2+) is a well-established therapeutic target in gastric and breast cancer. HER2is positive in approximately 5% of CRC cases and has been implicated in resistance to therapy with anti-epidermal growth factor receptor antibodies. The aim of this study was to evaluate HER2 status in RAS and BRAF wild-type metastatic CRC (mCRC) and its correlation with survival outcomes. A single-center retrospective analysis of RAS and BRAF wild-type mCRC patients undergoing systemic treatment was conducted from July 2014 to September 2020. Tissue HER2 status was determined by immunohistochemistry (IHC) and/or fluorescence in situ hybridization (FISH) and/or chromogenic in situ hybridization (CISH). HER2+ was defined as IHC3 (+) or IHC2 (+) through FISH or CISH (+). Fifty-nine patients were included. The median age of all the included patients was 64 years (33-82). Four patients had HER2+ tumors (7%). Four patients had HER2+ tumors (7%).The majority of HER2+ mCRC cases were males (n=3) and left-sided CRC (n=3). All patients received FOLFIRI plus cetuximab as first-line treatment. At the median follow-up of 24.0 months, patients with HER2-negative mCRC presented with a median overall survival (mOS) of 39.4 months (95% confidence interval (CI) 32.7-46.0) and the four patients with HER2+ mCRC had a mOS of 20.4 months(95% CI; 9.5-31.3; p=0.07). In HER2-negative patients, themedian PFS (mPFS) was 11.3 months (95% CI; 9.2-13.4) vsHER2-positive patients with a mPFS of 10.9 months (95% CI; 1.3-20.4;p=0.47). To our knowledge, this is the first study reporting HER2+ in mCRC patients in a Portuguese population and the HER2+ rate was consistent with previous studies. Our study suggests that HER2+ may potentially be a marker that is able to predict poor prognosis in RAS and BRAF wild-type mCRC.

Assessment of the Impact of Alternative Fixatives on HER2 Detection in Breast Cancer and Gastric Cancer Tumor Specimens.

The type of fixative used for preserving tumor specimens can significantly impact the performance of the immunohistochemistry and in situ hybridization assays used for assessing human epidermal growth factor receptor 2 (HER2) status. This study reports the prevalence of the use of alternative fixatives other than the guideline-recommended 10% neutral buffered formalin (NBF) during HER2 testing in a real-world setting. The effects of alternative fixatives [20% NBF and 10% unbuffered formalin (UBF) fixatives] on HER2 testing of breast cancer (BC) and gastric cancer (GC) cell lines and tissues are also assessed. Overall, 117,636 tumor samples received at a central laboratory from >8000 clinical trial sites across 60 countries were reviewed to determine the prevalence of alternative fixative usage. To investigate the impact of alternative fixatives, 27 cell lines (21 BC and 6 GC) and 76 tumor tissue samples (50 BC and 26 GC) were fixed in 10% NBF, 20% NBF, or 10% UBF, and evaluated for HER2 status by immunohistochemistry and in situ hybridization. Real-world data showed that 9195 (7.8%) tumor samples were preserved using an alternative fixative. In cell lines, overall percentage agreement, negative percentage agreement, and positive percentage agreement among the 3 fixatives were 100%. In tumor tissues, the agreement among 10% NBF, 20% NBF, and 10% UBF ranged between 94.7% and 96.6% for negative percentage agreement and 90.9% for overall percentage agreement compared with a range of 58.3% to 66.7% for positive percentage agreement. These results suggest that alternative fixatives may have the potential to convert HER2 status in tissues from positive to negative.

Identifying HER2 from serum-derived exosomes in advanced gastric cancer as a promising biomarker for assessing tissue HER2 status and predicting the efficacy of trastuzumab-based therapy.

This study aimed to evaluate the clinical relevance of exosomal HER2 (Exo HER2) level in assessing the tissue HER2 status and predicting the efficacy of trastuzumab treatment. In this prospective study, patients with advanced gastric cancer (AGC) from three hospitals between August 2016 to November 2020 were enrolled. The Exo HER2 level was detected by enzyme-linked immunosorbent assay. Receiver operating characteristic curve (ROC) was drawn referring to the HER2 tissue status to assess the diagnostic value of Exo HER2. Cox proportional hazards regression and logistic regression were used to evaluate the association between Exo HER2 and progression-free survival (PFS), overall survival (OS), and objective response rate (ORR) in patients who received trastuzumab-based first-line therapy. In this study, 242 patients with advanced or metastatic gastric adenocarcinoma were registered. Of these, 238 AGC patients were eligible for evaluating serum-derived exosome HER2 diagnostic value, including 114 HER2-positive. Finally, 64 were eligible for efficacy analysis. The area under the ROC curve was 0.746. The optimal cutoff value for diagnosing tissue HER2-positive status was 729.95 ng/ml, with a sensitivity of 66.7% and a specificity of 74.2%. In 64 patients treated with trastuzumab, higher baseline Exo HER2 level indicated better prognosis. 844 ng/ml and 723 ng/ml were the right cutoffs for distinguishing the population with superior PFS (hazard ratio [HR]=0.41, P= 0.017) and OS (HR=0.30, P< 0.001), respectively. Serum exosomal HER2 level might serve as an effective biomarker for assessing tissue HER2 status in AGC and screening the potential patients who might benefit from anti-HER2 therapy.

Liquid Biopsy and Tissue Biopsy Comparison with Digital PCR and IHC/FISH for HER2 Amplification Detection in Breast Cancer Patients.

Two hundred twenty-four breast cancer patients with paired tissue and plasma samples were enrolled from 3 clinical centers to evaluate sensitivity and specificity of a digital PCR HER2 amplification assay. All patients were histologically confirmed diagnosis of locally advanced and recurrent or metastatic breast cancer with stage III/IV and had tissue HER2 status determinations using IHC/FISH. For the whole 224 advanced breast cancer patients, the sensitivity between dPCR in plasma and IHC/FISH in tissue samples is 43.75% (42/96), the specificity is 84.38% (108/128) and the overall concordance is 66.96% (150/224). Interestingly, when we looked at stage III, stage IV and recurrent or metastatic breast cancer separately, compared with IHC/FISH in tissue samples, the sensitivity of dPCR in plasma increases from 37.93% (11/29) for stage III to 41.67% (15/36) for stage IV cancer. Recurrent breast cancer patient had an increased sensitivity of 51.61% (16/31). This is consistent with our expectation sensitivity would increase concordantly as tumor burden goes up. On the other hand, specificity decreased from 92.68% (38/41) for stage III to 86.44% (51/59) for stage IV cancer. Recurrent breast cancer patient had a specificity of only 67.86% (19/28). This is, in part, due to inter- and intra-tumor heterogeneity. Many patients determined to be negative for HER2 amplification in tissue biopsy could have HER2 positive tumors at other sites, which was detected by the liquid biopsy. This study suggested the necessity of liquid biopsy for HER2 amplification detection and demonstrated digital PCR can be used as a companion diagnostic tool to determine HER2 amplification status. It also suggested that a liquid biopsy should follow a negative result from tissue biopsy to avoid false negative results especially for late-stage breast cancer patients and ones who experienced relapse or became resistant to current therapy. Future studies should focus on therapeutic effects on patients determined to be HER2 positive through liquid biopsy and collecting additional tissue biopsies to identify HER2 positive tumor when the original tissue biopsy and liquid biopsy don't agree.

Utility of Serum HER-2/ neu in Prediction of Tissue HER-2 /neu Status of Primary Breast Cancer

Background: The use of biomarkers has become increasingly important in the diagnosis and treatment of several malignancies, including breast cancer. Among the established biomarkers, receptor tyrosine-protein kinase erbB-2 (HER-2/ neu) has been found to be of a predictive and prognostic role in breast cancer patients. Method: 94 patients with primary breast cancer were enrolled in our prospective study between 2016 and 2017. 5 cc clot blood samples were taken for serum HER-2/neu testing at the time of diagnosis of breast cancer. The patients’ demographic data, tumor characteristics, including tumor size, tumor grade, presence of lymph node involvement, and stage, hormone receptor, and tissue HER-2/neu status of the subjects were recorded following tumor removal. Results: All of them were female with the age range of 27 to 80 years (the mean of age was 49.66. 36 patients (38.3%) had positive tissue HER-2 results and 58 patients (61.7%) had negative results. In those with high level serum HER-2 ECD, 28(77.7%) had positive tissue HER-2 and 8(22.2%) had negative results. Moreover, in the patients with low level serum HER-2 ECD, 8(13.7%) had positive tissue HER-2 and 50(86.2%) had negative results with the sensitivity of 77.7% and specificity of 86.2%. HER2 ECD levels were highly concordant with tissue HER2 status, with a P value of less than 0.001, which was considered to be statistically significant. Among different clinic –pathologic variables, serum and tissue HER-2/nu were significantly correlated with only tumor grade. Conclusion: A significantly increased release of HER2 ECD levels may accurately predict tumor HER2 status as detected with IHC and/or in situ hybridizations studies.

Comparative analysis of HER2 copy number between plasma and tissue samples in gastric cancer using droplet digital PCR

In this study, we measured the human epidermal growth factor receptor 2 (HER2) copy number in both tissue and plasma samples of gastric cancer patients by using droplet digital polymerase chain reaction (ddPCR) method. Eighty gastric cancer patients were enrolled and both formalin-fixed and paraffin-embedded tissue and preoperative plasma samples were collected. HER2 status was determined by HER2 immunohistochemistry (IHC)/silver in situ hybridization (SISH) in tissue samples and ddPCR of the target gene HER2 and the reference gene eukaryotic translation initiation factor 2C, 1 in both tissue and plasma. The concordance rate of tissue HER2 status determined by IHC/SISH and HER2 ddPCR was 90.0% (72/80), and the sensitivity and specificity of tissue ddPCR were 85.0% and 95.0%, respectively. The concordance rate of plasma ddPCR and IHC/SISH was 63.8% (51/80). The sensitivity, specificity, positive predictive value, and negative predictive value of plasma HER2 ddPCR were 37.5%, 90.0%, 79.0%, and 59.0%, respectively. As HER2 measurement by tissue ddPCR showed a high concordance rate with HER2 status by IHC/SISH, it could replace tissue IHC/SISH testing in gastric cancer. These findings may contribute to the development of tissue and plasma HER2 testing that would be useful in daily practice.

Shed HER2 surrogacy evaluation in primary breast cancer patients: a study assessing tumor tissue HER2 expression at both extracellular and intracellular levels

The aim of the present study was to investigate serum HER2 extracellular domain (ECD) as a putative surrogate marker of the shedding phenomenon of HER2 receptor from the tumor tissue of primary breast cancer (BC) patients. A pilot retrospective study was conducted on 100 matched serum and tissue samples from patients with node-positive primary BC, stage II/III. Analysis of association and concordance between serum HER2 ECD levels (measured by chemiluminescence immunoassay) and the expression in matched tumor tissue of HER2 ECD and intracellular receptor domain (ICD) (determined by immunohistochemistry) were performed. The median serum HER2 ECD level was 9.4 ng/ml and cutoff values were set at 15.2 ng/ml or 13.0 ng/ml. HER2 ICD and ECD were overexpressed in tumor tissue of 19.8% and 6.9% of patients, respectively. Statistically significant associations were found between serum HER2 ECD levels and tissue expression of both HER2 ICD and ECD (p < .001; Fisher analysis). Moreover, strong concordances were found between serum HER2 ECD levels and tissue expression of HER2 ICD or ECD (cutoff 15.2 ng/ml: 80 and 92.5%, respectively). Our findings support a role for serum HER2 ECD as a surrogate marker of tissue HER2 status in primary BC, both for HER2 ICD or ECD expression.

HER2 decreases drug sensitivity of ovarian cancer cells via inducing stem cell-like property in an NFκB-dependent way.

Increasing evidence shows that cancer stem cells are responsible for drug resistance and relapse of tumors. In breast cancer, human epidermal growth factor receptor 2 (HER2) induces Herceptin resistance by inducing cancer stem cells. In the present study, we explored the effect of HER2 on cancer stem cells induction and drug sensitivity of ovarian cancer cell lines. First, we found that HER2 overexpression (HER2 OE) induced, while HER2 knockdown (HER2 KD) decreased CD44+/CD24− population. Consistently, HER2 expression was closely correlated with the sphere formation efficiency (SFE) of ovarian cancer cells. Second, we found that NFκB inhibition by specific inhibitor JSH23 or siRNA targetting subunit p65 dramatically impaired the induction of ovarian cancer stem cells by HER2, indicating that NFκB mediated HER2-induced ovarian cancer stem cells. Third, we found that HER2 KD significantly attenuated the tumorigenicity of ovarian cancer cells. Further, we found that HER2 inhibition increased drastically the sensitivity of ovarian cancer cells to doxorubicin (DOX) or paclitaxel (PTX). Finally, we examined the correlation between HER2 status and stem cell-related genes expression in human ovarian tumor tissues, and found that expressions of OCT4, COX2, and Nanog were higher in HER2 positive tumors than in HER2 negative tumors. Consistently, the 5-year tumor-free survival rate of HER2 positive patients was dramatically lower than HER2 negative patients. Taken together, our data indicate that HER2 decreases drug sensitivity of ovarian cancer cells via inducing stem cell-like property.

Abstract P4-01-05: Cell free DNA analysis identifies actionable ERBB2 amplifications in patients with HER2 equivocal breast cancer

Abstract Background: Determination of ERBB2 (HER2) expression or amplification informs eligibility of HER2-targeted therapies. ASCO and NCCN guidelines recommend evaluation of HER2 status on primary invasive breast cancers and on a metastatic site if stage IV, where possible, as treatment is based on the status of the metastasis. Reassessment of HER2 status should also be considered in patients with disease recurrence as initially HER2-negative tumors may acquire HER2 amplification at progression. HER2 status can be complicated by equivocal results from in situ hybridization (ISH) and/or immunohistochemistry (IHC). Clarification requires reflex testing on the same tissue specimen or repeat testing on a new specimen, however some patients' tissue status remains equivocal. Furthermore, metastases to bone, lung, or brain may be difficult to re-biopsy or of low DNA quality. Rapid and non-invasive blood-based cell-free DNA (cfDNA) NGS may facilitate identification of HER2 targetable disease in advanced breast cancer. Methods: We assessed the frequency of ERBB2 amplification detectable by a blood-based cell-free DNA (cfDNA) assay among patients with metastatic breast cancer with equivocal HER2 results in tissue. cfDNA samples were ordered as part of routine clinical care using an assay validated for the detection of copy number amplification in ERBB2 (tests run between 03/2014-04/2017 by Guardant Health, Redwood City, CA). Submitted pathology reports were reviewed for HER2 status which was categorized as positive, negative, or equivocal based on the interpretation issued by the reading pathologist at the time the test was ordered. Patients were included if they had an equivocal result on IHC and/or ISH unless both assays were performed on the same specimen and one provided a definitive negative or positive HER2 result. Additionally, 4 patients with equivocal IHC or ISH results were excluded as biopsy of another tumor site revealed a positive HER2 result around the same time as the equivocal test. For the 349 patients with multiple cfDNA samples, the earliest pathology report was referenced. Results: Tissue HER2 status was available for 1,853 unique patients (98.8% female, median age at testing was 58y, range 26-91y). 141 patients (7.6%) had equivocal HER2 results in tissue; 99 by IHC alone, 14 by ISH alone, and 28 were equivocal by both assays. Among these, 126 patients (89.4%) had at least one sample with ctDNA detected. 12/126 (9.5%) had amplification of ERBB2 detected in at least one cfDNA sample. Samples were drawn a median of 267 days after tissue collection (range 4 days – 11.5 years). Frequency of ERBB2 amplification was similar regardless of time between tissue and blood collection but was higher among patients with ISH results alone (4/14, 36.4%) compared to those with IHC alone (6/89, 6.7%) or both assays (6/26, 7.6%; p=0.006). Conclusion: cfDNA testing identifies a significant number of patients with HER2-targetable advanced breast cancer whose tissue was HER2 equivocal. cfDNA testing may supplement tissue-based methods to help clarify HER2 status in metastatic disease as well as identify patients who may acquire HER2 amplification subsequent to their initial biopsy. Citation Format: Rich TA, Raymond VM, Ahn ER, Banks KC, Brufsky A, Lee C, Lippman M, Pluard TJ, Schwab RB, Lanman RB. Cell free DNA analysis identifies actionable ERBB2 amplifications in patients with HER2 equivocal breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-01-05.

Portable detection of serum HER-2 in breast cancer by a pressure-based platform.

A high serum HER-2 extracellular domain (sHER-2 ECD) level has a reverse association with tumor behaviors. In this study, a portable platform for the disease biomarker sHER-2 ECD detection has been established using a pressure-based bioassay. The pressure bioassay consists of a monoclonal antibody immobilized on an eight-well strip, the analyte HER-2, and another monoclonal antibody labeled with the Pt nanoparticles (PtNPs), which have the catalytic ability to decompose H2O2 into H2O and O2(g). The increased pressure due to O2(g) generation is measured by a hand-held pressure meter. A total of 34 serum samples were collected to validate the performance of the pressure bioassay. The results showed that the pressure bioassay platform of HER-2 had a dynamic range from 2 to 50ng/mL with a limit of detection (LOD) of 2ng/mL, which was consistent with the ELISA result. In the real serum samples, there was a significant correlation between sHER-2 ECD level and several clinicopathological parameters, especially tissue HER-2 status. Furthermore, the sHER-2 ECD level was found to decrease after targeted therapy in a patient with tHER-2 positive. Overall, this bioassay can facilitate breast cancer diagnosis and prognosis in clinical scenarios and resource-limited areas.

Abstract 5592: HER-2 copy number measurement in tissue and cell-free plasma DNA of gastric cancer patients using droplet digital PCR method

Abstract In around 10% of gastric cancer, amplification and overexpression of the human epidermal growth factor receptor 2 (HER2) is observed and trastuzumab is adopted as a target therapy agent for HER2-positive gastric cancer. Because of efficiency and accuracy, droplet digital PCR (ddPCR) is one of the best methods for measuring HER2 amplification, especially in cell-free plasma samples. In this study, we aimed to investigate the correlation between tissue and plasma HER2 status by using ddPCR method in gastric cancer patients. We collected formalin-fixed and paraffin-embedded tissue (FFPE) and cell-free plasma samples of 81 gastric cancer patients, including 30 HER2 immunohistochemistry (IHC)-negative (0 or 1+) cases and 51 HER2 IHC-positive cases (IHC 2+, n=20; IHC 3+, n=31), with informed consents. We performed ddPCR of a target gene HER2 and a reference gene EIF2C1 in both tissue and cell-free plasma samples, and gene copy number (GCN) of HER2 was calculated. The median HER2 GCN of tissue DNA ddPCR was 2.61 (1.47-49.00) and the median GCN of plasma ddPCR was 1.83 (0.97-7.67). HER2 IHC results showed moderate correlation with HER2 GCN of tissue ddPCR (r=0.455, p&amp;lt;0.001) and weak correlation with plasma ddPCR (r=0.321, p=0.003). A ratio &amp;gt;2.405, which showed the best discriminating level from a receiver operating characteristic curve, was defined as a cut-off for tissue HER2 amplification using ddPCR method. Comparing the HER2 amplification results of tissue DNA ddPCR to HER2 IHC results, the concordance rate was 86.4% with Cohen's kappa of 0.715. Sensitivity and specificity of tissue ddPCR were 86.3% and 86.7%, respectively. HER2 amplification by tissue ddPCR was significantly associated with advanced gastric cancer and lymphatic invasion (p&amp;lt;0.05). HER2 GCN of tissue ddPCR was weakly correlated with plasma ddPCR (r=0.250, p=0.025). Sensitivity and specificity of plasma ddPCR for HER2 IHC positivity were 35.3% and 93.3%, respectively. However, sensitivity and specificity of plasma ddPCR were 66.7% and 60.0% with another cut-off of 1.715. In 51 HER2 IHC-positive cases, intratumoral heterogeneity was observed in 100% (5/5) of both tissue and plasma ddPCR-negative cases, 100% (2/2) of tissue-negative and plasma positive cases, 64.3% (18/28) of tissue-positive and plasma-negative cases, and 50.0% (8/16) of both positive cases (p=0.026). In conclusion, HER2 GCN of plasma ddPCR showed a weak correlation with tissue ddPCR, and the sensitivity of plasma ddPCR was not high. Intratumoral heterogeneity is suggested to be one of the possible causes, and these findings may contribute to developing plasma HER2 testing useful in daily practice. Citation Format: Boram Kim, Soo Kyung Nam, Soo Hyun Seo, Sang-Hoon Ahn, Do Joong Park, Hyung-Ho Kim, Kyoung Un Park, Hye Seoung Lee. HER-2 copy number measurement in tissue and cell-free plasma DNA of gastric cancer patients using droplet digital PCR method [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5592.

Aptamer based fluorescent probe for serum HER2-ECD detection: The clinical utility in breast cancer

The transmembrane protein HER2 is overexpressed in approximately 30% of breast cancer patients. HER2-positive breast cancers tend to spread more aggressively, which result in increased mortality in women. Nowadays, the real-time monitoring of HER2 status is important in clinical diagnosis and treatment for HER2-positive patients. Although IHC and FISH assay are standard methods to evaluate the tissue HER2 status, both approaches which required high quality tissue samples and are not suitable for monitoring the status of HER2 in real time. Since extracellular domain (ECD) of the HER2 receptor can be shed into the circulation, the serum test of HER2 ECD has been developed as an additional approach to probe HER2 overexpression. The serum test will be able to monitor the dynamic changes of HER2 status. In this paper, we detected serum HER2 ECD using Cy5-labeled HB5 aptamer as a result of its specific binding ability to HER2 ECD. This aptamer-based fluorescent probe is easily synthesized and modified and as sensitive as anti-HER2 antibodies. We believe that Cy5-HB5 may have application potentials in serum HER2 test for clinical utility of breast cancer, such as recurrence and metastases.

Preclinical study of antitumor activity of trastuzumab emtansine in HER2-positive biliary tract cancer.

256 Background: Trastuzumab emtansine (T-DM1) is an antibody-drug conjugate composed of trastuzumab and DM1 (an anti-microtubule agent derived from maytansine) that is approved for the treatment of HER2-positive metastatic breast cancer. HER2-overexpression rate in biliary tract cancer (BTC) is reported as approximately 10%, and HER2-targeted therapy may enhance therapeutic efficacy in HER2-positive BTC. In this study, we investigated the antitumor activity of T-DM1 in several BTC cell lines and xenograft models. Methods: HER2 expression was detected by flow cytometry and Western blotting in 17 BTC cell lines. The cell growth inhibition activity of T-DM1 and DM1 was examined by quantifying the DNA with Hoechst 33258 nucleic acid stain. In vivo antitumor activity of T-DM1 was evaluated in three xenograft mouse models using cell lines with different levels of HER2 expression. HER2 expression in xenografts was assessed by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH), according to gastric cancer criteria. Cell cycle was assessed by flow cytometry after staining with propidium iodide. Apoptosis was assessed by caspase 3/7 activity measurement. Results: In the 17 BTC cell lines, HER2 expression was high in KMCH-1, Mz-ChA-1, and TGBC-18-TKB. Although cell growth inhibition of DM1 was similar in all cell lines (50% inhibitory concentration (IC50): 0.79–7.2 nM), that of T-DM1 was HER2-expression-dependent, with IC50 values in KMCH-1, Mz-ChA-1, and KKU-100 (which has low HER2 expression) of 0.031, 1.3, and 4.3 μg/mL, respectively. In KMCH-1 and Mz-ChA-1 xenograft models, T-DM1 treatment once every 3 weeks for 6 weeks showed significant dose-dependent antitumor activity, and tumor growth inhibition 21 days after first dose at 20 mg/kg T-DM1 was 108% (KMCH-1) and 75% (Mz-ChA-1), whereas there was no significant efficacy in KKU-100 xenograft model. Values for HER2 status (IHC score/FISH ratio of HER2 to CEP17) in KMCH-1, Mz-ChA-1, and KKU-100 tumor tissues were 3+/3.5, 2+/4.7, and 0/1.1, respectively. In KMCH-1, T-DM1 induced M phase arrest and apoptosis, as is reported in HER2-positive breast cancer cells. Conclusions: T-DM1 could be an effective therapy for HER2-overexpressed BTC.

Serum HER2 level during chemotherapy as a biomarker for advanced gastric cancer.

29 Background: Recent studies showed that serum HER2 levels correlated with tissue HER2 status in gastric cancer. The aim of this prospective study (UMIN000006442, 000006445) was to investigate changes in serum HER2 levels and tissue HER2 status during chemotherapy for advanced gastric cancer (AGC). Methods: Chemotherapy (Capecitabine and cisplatin) with and without trastuzumab was administered to patients with HER2-positive and HER2-negative AGC, respectively. Serum HER2 level was measured using chemiluminescense immunoassay (CLIA) at 4 points: at the initial diagnosis, after two cycles of chemotherapy, at the initial evaluation of tumor response, and at the time of progression. If possible, second biopsy was performed at progression to compare tissue HER2 status before and after chemotherapy. Results: Thirty-three patients (14 HER2-positive and 19 HER2-negative) with a median age of 67 years (range 51-80) were recruited. The median baseline serum HER2 level of the HER2-positive group was significantly higher than that of the HER2-negative group (p = 0.038, 12.0 ng/ml (range 6.5-148.0) and 8.2 ng/ml (4.5-27.2), respectively). A Decrease in serum HER2 level was correlated with tumor response in the HER2-positive group while it was not in the HER2-negative group. Tissue samples at the time of progression were obtained in 6 out of 19 HER2-negative cases. Of these, serum HER2 level elevated at progression in 4 cases, and tissue HER2 status has turned to positive at tumor progression in one case. In the HER2-positive group, tissue samples at tumor progression were obtained in 2 cases, and both showed HER2-positive result, same as the initial diagnosis. Conclusions: Serum HER2 could be useful as a response indicator in HER2-positive AGC. Tissue HER2 status may change from negative to positive over time and serum HER2 has a possibility to predict it. Further studies are needed to confirm these findings. Clinical trial information: UMIN000006442,000006445.

Serum HER2 as a predictive biomarker for tissue HER2 status and prognosis in patients with gastric cancer.

AIMTo investigate the association between serum human epidermal growth factor receptor 2 (HER2) extracellular domain (ECD) and tissue HER2 status, and the prognostic value of serum HER2 ECD in patients with gastric cancer.METHODSA total of 239 patients with gastric cancer were enrolled from December 2012 to June 2013. Serum HER2 ECD was determined by chemiluminescent assay, and tissue HER2 status was evaluated by immunohistochemistry and fluorescence in situ hybridization assay. A receiver operating characteristic (ROC) curve was plotted to identify the optimal cut-off value for serum HER2 ECD assay for predicting survival in gastric cancer patients.RESULTSSerum HER2 ECD was significantly correlated with tissue HER2 status (P < 0.001), tumor size (P < 0.001), and intestinal type of gastric cancer (P = 0.021). Serum HER2 ECD levels differed significantly between patients with HER2-positive tissue expression and those with HER2-negative tissue expression. ROC analysis yielded an area under the curve value of 0.79 (95%CI: 0.71-0.87, P < 0.001), with a sensitivity and specificity of 0.54 (95%CI: 0.37-0.70) and 0.93 (95%CI: 0.88-0.96), respectively. With a cut-off value of 24.75 ng/mL, high serum HER2 ECD had a negative impact on overall survival of the patients (HR: 1.93, 95%CI: 1.32-4.38, P = 0.006).CONCLUSIONSerum HER2 ECD could be a highly specific surrogate biomarker for tissue HER2 status in gastric cancer. Optimal cut-off criteria for predicting survival should be established.

The Significance of Serum HER2 Levels at Diagnosis on Intrinsic Subtype-Specific Outcome of Operable Breast Cancer Patients.

PurposeThis study evaluated the association of serum HER2 (sHER2) levels at diagnosis with clinicopathologic parameters and disease free survival (DFS) in operable breast cancer patients according to intrinsic subtype.MethodsThe sHER2 levels were measured using a chemiluminescence immunoassay. The HER2 status in all tumor tissues was determined by immunohistochemistry, and confirmed in equivocal cases by fluorescence in situ.ResultsThere were 436 consecutive stage I-III breast cancer patients with sHER2 result at diagnosis between Nov 2004 and Dec 2011. High sHER2 levels (≥ 15 ng/ml) were reported in 52 patients (11.9%) and HER2 overexpression in tumor tissue was observed in 111 patients (25.5%). High sHER2 levels were associated significantly with advanced stage (P < 0.001), mastectomy (P = 0.012), neoadjuvant chemotherapy (P < 0.001), anti-HER2 therapy (P < 0.001) and hormone therapy (P = 0.022). The patients with high sHER2 levels had a worse DFS (P < 0.001). In multivariate analysis, high sHER2 levels were associated significantly with worse DFS (HR = 2.25, 95% CI 1.27–3.99, P = 0.005). High sHER2 levels were associated with worse DFS in the HR+/HER2-, HR+/HER2+ and HR-/HER2+ subtypes (P = 0.043, 0.003 and 0.041, respectively).ConclusionsThese results show that the sHER2 level at diagnosis is a useful prognostic factor in patients with operable breast cancer, especially in the HR+/HER2-, HR+/HER2+ and HR-/HER2+ subtypes.

Serum HER2 levels are increased in cats with mammary carcinomas and predict tissue HER2 status.

HER2 is overexpressed in about 30% of feline mammary carcinomas (FMC) and in 15-30% of breast cancers. Women with HER2-positive breast tumors are associated with shorter survival. This study aimed to optimize the detection and quantification of serum HER2 (sHER2) in cats and to evaluate its potential in diagnosing cats with mammary carcinomas (MC) overexpressing HER2. A prospective study was conducted in 60 queens showing MC and 20 healthy animals. Pre-operative serum samples were collected for sHER2 quantification using two immunoassays: ELISA and Dot blot assay. sHER2 levels were compared with tissue HER2 status assessed by immunohistochemistry. Queens with FMC showed significantly higher mean levels of sHER2 by both ELISA and Dot blot assay. A significant difference in the sHER2 levels was also found between cats with HER2-positive MC and those with low-expressing HER2 MC. A significant correlation between sHER2 levels and tumor HER2 status was also found, particularly when ELISA was used (r = 0.58, p < 0.0001). The value of 10 ng/ml was proposed as the optimal cutoff for both immunoassays by ROC analysis. Like in humans, sHER2 levels are increased in cats with MC HER2-positive, strongly suggesting that evaluation of sHER2 levels can be very useful in feline oncology. The results show that ELISA and Dot blot assay can replace the immunohistochemistry technique, due to their efficacy and lower costs for diagnostic purposes and for monitoring the response to anti-HER2 therapies in cats.

Serum HER2 as an adjunct to assess HER2 status for advanced gastric cancer: A prospective multicenter trial (SHERLOCK)

Background: Intratumoral human epidermal growth factor receptor 2 (HER2) heterogeneity of gastric cancer can be an obstacle to accurate HER2 assessment. Serum HER2, concentrations of the HER2 extracellular domain shed into the bloodstream, has a potential to compensate HER2 immunohistochemistry (IHC) but has not been scrutinized in gastric cancer. This study sought to explore the clinical utility of serum HER2 in gastric cancer.Methods: We performed a prospective multicenter trial (SHERLOCK trial) involving patients with all-stage gastric or gastro-esophageal junction cancer. Serum HER2 was measured using direct chemiluminescence while tissue HER2 status was determined using IHC and fluorescent in situ hybridization. For stage IV cases, concordance between local and central laboratories in tissue HER2 assessment was also evaluated.Results: Of 224 patients enrolled, both tissue HER2 status and serum HER2 levels were successfully determined in 212 patients and 21% (45/212) were tissue HER2-positive. Serum HER2 levels, ranged from 4.5 to 148.0 ng/ml (median 10.3), correlated with tissue HER2 status (p = 0.003). At a cut-off level of 28.0 ng/ml determined by receiver operating characteristics analysis, sensitivity, specificity, positive and negative predictive values of serum HER2 were 22.6%, 100%, 100% and 82.3%, respectively. All nine cases with elevated serum HER2 were tissue HER2-positive stage IV cases. Among 61 stage IV cases, the agreement rate for IHC scoring between the local and the central laboratories was 82% and tissue HER2 judgment was conflicting in five (8.2%) cases. Of these five cases, four were confirmed as false-negative and two of these four patients demonstrated elevated serum HER2.Conclusions: Serum HER2 levels correlated with tissue HER2 status in gastric cancer. Although the low sensitivity is a drawback, serum HER2 might be a useful adjunct tool to detect tissue HER2 false-negative gastric cancer.