Human Epidermal Growth Factor Receptor-2 Expression Research Articles

Retrospective analysis of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor-2 (HER2), Ki67 changes and their clinical significance between primary breast cancer and metastatic tumors.

To explore the relationship between receptor heterogeneity and clinicopathological characteristics in 166 patients with invasive breast cancer during metastasis. We conducted a retrospective analysis of 166 patients diagnosed with metastatic breast cancer through biopsy, who were admitted to our hospital from January 2018 to December 2022. Statistical analysis was employed to assess the heterogeneity of receptors in both primary and metastatic lesions, including estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor-2 (HER2), Ki67, as well as their association with clinicopathological features such as tumor size, lymph node metastasis, treatment regimen, and disease-free survival. The discordant expression rates of ER, PR, HER2, Ki-67 and Luminal classification between primary and metastatic lesions were 21.7%, 41.6%, 8.9%, 34.4% and 36.8%, respectively. There is a significant difference in disease-free survival between patients with consistent and inconsistent receptor status of primary and metastatic lesions, which is statistically significant. The median DFS for primary HER2(-) to metastatic HER2(+) was 84 months, which was relatively high. The Cox multivariate regression analysis revealed that the expression differences of ER, PR, HER2, and Ki67 were not influenced by endocrine therapy and chemotherapy. However, a statistically significant difference in HER2 expression was observed with targeted therapy. Tumor size was correlated with ER and Ki67 receptor status (P=0.019, 0.016). Tumor size was not correlated with PR, and HER2 (P=0.679, 0.440). Lymph node metastasis was not associated with changes in ER, PR, HER2, and Ki67. The discordant rates of ER, PR, HER2, and Ki-67 in patients with local recurrence were 22%, 23.7%, 5.1%, and 28.8% respectively, whereas those in patients with distant metastasis were 21.5%, 36.4%, 10.3%, and 31.8% respectively. The expression levels of ER, PR, HER2, and Ki-67 in primary and metastatic breast cancer exhibit heterogeneity, which is closely associated with the prognosis and treatment outcomes of patients.

Abstract PO2-02-07: Clinicopathological Features and Prognostic Role of HER2 Low in Early Breast Cancer: A real world study

Abstract Background: The definition of human epidermal growth factor receptor-2(HER2) low was proposed with the development of T-DXd, a novel antibody-drug conjugate (ADCs) targeting HER2 in the field of breast cancer (BC) treatments. However, whether HER2 low is a distinct subgroup is still an ongoing debate with mixed results. Current retrospective studies focused on HER2 low concentrated more on metastatic BC, less was known in early BC. The retrospective study was conducted based on HER2 low early BC to comprehensively analyze its clinicopathological features and prognostic roles compared with HER2 IHC0. Methods: This single institution retrospective study enrolled 999 early stage (stage I through III) HER2 negative invasive BC patients diagnosed at Chinese PLA General Hospital from January 2010 to December 2015. Tumors with HER2 immunohistochemical (IHC) score of 1+ or 2+ with negative in situ hybridization assay were defined as HER2 low. Clinicopathological characteristics s and survival outcomes including disease-free survival (DFS) and overall survival (OS) were compared between HER2 IHC0 and HER2 low groups. The correlations between HER2 expression and estrogen receptor (ER) status were determined by Mantel-Haenszel χ2 test. Cohen’s kappa coefficient (k) was adopted to evaluate the concordance between HER2 expression on primary tumors and matched biopsies. Results: 999 patients were eligible for inclusion criteria, among which the percentages of HER2 low in the whole cohort, HR positive group and HR negative group were 83.6%, 86.54%, 72.14% respectively. It was observed the presence of a significant higher proportion of ER level > 10% (p < 0.001), PgR positive (p < 0.001) and more patients who received endocrine therapy (p = 0.002). In HR positive group, clinicopathological features were balanced between HER2 IHC0 and HER2 low. In HR negative group, HER2 low manifested a higher proportion of invasive ductal type (p = 0.016) compared with HER2 IHC0. Survival analysis showed a significantly longer OS in HER2 low BC than HER2 IHC0. (HR: 0.458, 95%CI: 0.262-0.800, p = 0.0005). Nevertheless, the independent role was not reached in DFS. When stratified by HR status, patients with HER2 low in HR positive group demonstrated a longer OS than HER2 IHC0 (HR: 0.55, 95%CI: 0.273-1.105, p = 0.0385). The same trend was observed in HR negative group (HR: 0.385, 95%CI: 0.158-0.939, p = 0.0132). Neither the HR positive group nor the HR negative group achieved significant DFS. Besides, a positive correlation was observed between ER status and the rate of HER2 low (Mantel-Haenszel c2 test, p < 0.001, Pearson’s R = 0.159, P < 0.001). No regularity of survival differences between HER2 IHC0 and HER2 low was found in each ER level in the exploratory study. Finally, 119 patients who developed relapsed or metastatic disease were identified, with the most prevalent metastatic site being bone (31.1%), following by lung (16.80%) and lymph node (13.44%). Among 52 patients with matched biopsy samples, dynamic changes of HER2 IHC status were confirmed in both primary and relapsed statuses, with an discordance rate of 28.84% (K = 0.194, 95%CI: 0.168-0.219). conclusion: HER2 low expression breast cancer may not be regarded as a unique BC group in this real-world population due to similar clinicopathological features and prognostic roles especially in hormone-receptor positive cases. ER level was positively correlated with the rate of HER2 low population. Overall, whether HER2 low is a distinct subgroup remains to be supported and validated by more data both in clinical and molecular levels. Key words: HER2 low; Breast cancer; Clinicopathological Features; Prognosis; Molecular type Clinicopathological Features and Prognostic Role of HER2 Low in Early Breast Cancer: A real world study Citation Format: Ziqing Kong, Weihong Zhao. Clinicopathological Features and Prognostic Role of HER2 Low in Early Breast Cancer: A real world study [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-02-07.

Abstract PO4-06-12: Distinction of basal-like and triple-negative basal-like breast cancers utilizing a novel comprehensive single-cell liquid biopsy-based test

Abstract Introduction: Breast cancer is a highly heterogeneous disease and is a leading cause of death for women worldwide. Triple-negative breast cancer (TNBC), the most aggressive form of the disease, is clinically defined by the lack of expression of estrogen receptor (ER) and progesterone receptor (PR), as well as lack of over-expression of human epidermal growth factor receptor-2 (HER2). Approximately 70% of all TNBC cases exhibit basal-like cells, characterized by high basal expression of keratins as well as extensive genomic instability with copy number gains and losses across most chromosomes. In this study we show that novel single cell genomic evaluation coupled with immunofluorescence (IF) protein analysis of CTCs can detect TNBC with basal-like genomic features as well as basal-like tumors with expression of ER and HER2. Materials and Methods: Epic Sciences’ DefineMBC™ liquid biopsy test characterizes CTC proteomics and genomics as well as ctDNA for the treatment of metastatic breast cancer. Blood samples from 813 metastatic breast cancer patients, with either newly diagnosed or progressing disease, with historical tissue subtype [HR(+)HER2(-), HR(+/-)HER2(+), and TNBC] supplied by the referring physician were collected and tested. Up to 5 CTCs were selected and isolated from each sample based on morphology and IF signal. DNA was extracted from individual cells, and whole genome amplified and sequenced at low coverage. Copy number analysis was performed to determine copy number gains and losses across chromosomes, as well as large scale-state transitions (LSTs) and ERBB2 amplification. CTCs characterized with high chromosomal instability (e.g., exhibiting >30 LSTs; 1Q firestorm and 8Q stair step) and high levels of cytokeratin expression (mean fluorescence intensity signal >10K) were categorized as basal-like. Results: By previous metastatic tissue biopsy, 77% were HR(+), 8% were HER2(+), and 12% were TNBC. CTCs categorized in DefineMBC as basal-like subtype (9.8 % of all samples tested) showed to be highly present in patients called as TNBC (79% basal-like). Additionally, 54% of HR(+) and 23% of HER2(+) had basal-like CTCS. Patients characterized with TNBC by metastatic tissue biopsy and by DefineMBC exhibited basal-like cells in 88% of the cases. Conclusion: The results show a novel clinical assay which utilizes CTC protein detection as well as single-cell genomic analysis to identify tumors driven by basal-like cells. Generally, TNBC is classified with negative biomarker expression. We show that CTCs in TNBC display genomically basal-like cells. CTCs from HR(+) and HER2(+) tumors may express basal-like features with preserved ER and HER2 expression. The comprehensive nature of DefineMBC™ utilizing genomic analysis of detected CTCs has provided a new tool to diagnose both basal-like TNBC and basal-like hormone receptor positive and HER2 over-expressing tumors. Citation Format: Alessandra Cunsolo, David Bourdon, Ernest Lam, Giuseppe Di Caro, Nilesh Dharajiya, Timothy Pluard, Lee Schwartzberg. Distinction of basal-like and triple-negative basal-like breast cancers utilizing a novel comprehensive single-cell liquid biopsy-based test [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-06-12.

Human epidermal growth factor receptor-2 expression and subsequent dynamic changes in patients with ovarian cancer

Human epidermal growth factor receptor-2 (HER2)-targeting drugs are increasingly being incorporated into therapeutic paradigms for non-breast cancers, yet studies on HER2 expression in ovarian cancer (OC) are inadequate. Here, we studied the HER2 status and dynamic changes in OC by reviewing the records of patients who underwent HER2 testing at a single institution. Clinical parameters, including histology, BRCA status, and immunohistochemistry (IHC), were evaluated alongside HER2 expression, timing, and anatomical location. Among 200 patients, 28% and 6% exhibited expression scores of 2+ and 3+, respectively. HER2 3+ scores were observed in 23%, 11%, 9%, and 5% of mucinous, endometrioid, clear cell, and high-grade serous tumors, respectively, and were exclusively identified in BRCA-wildtype, mismatch repair-proficient, or PD-L1-low-expressing tumors. The TP53 mutation rate was low, whereas ARID1A, KRAS, and PIK3CA mutations were relatively more prevalent with HER2 scores of 2+ or 3+ than with 0 or 1+. Four of the five tumors with an HER2 3+ score exhibited ERBB2 amplification. Among 19 patients who underwent multiple time-lagged biopsies, 11 showed increased HER2 expression in subsequent biopsies. Patients with HER2-overexpressing OC exhibited distinct histological, IHC, and genomic profiles. HER2-targeting agents are potential options for BRCA-wildtype patients, particularly as later lines of treatment.

Abstract 4696: ERBB2 signaling and inhibition in bladder cancer

Abstract The role of human epidermal growth factor receptor-2 (HER2) protein and the inhibition of its oncogenic signaling pathway, ERBB2, is well defined and found to be beneficial in combination with standard chemotherapies in breast and certain gastro-intestinal cancers. Targeting the ERBB2 pathway has had unclear or inconsistent results in early trials in bladder cancer (BLCA) and the efficacy of its combination with cisplatin, a standard BLCA chemotherapy, is not known. In this study, we identify the transcriptomic oncogenic signatures that correlate with ERBB2 signaling in BLCA, explore how HER2 expression in BLCA cell lines correlates with treatment response in vitro, and evaluate the potential of ERBB2 inhibition in combination with cisplatin for BLCA. We analyzed the tumor transcriptome from the Cancer Genome Atlas (TCGA) study of BLCA with single sample Gene Set Enrichment Analyses (ssGSEA) for Hallmark and Oncogenic gene sets. We performed multiple Pearson correlation analyses of HER2 protein levels and ERBB2 signaling with other signaling pathways in the TCGA BLCA tumors and adjusted the significance for multiple comparisons using the Benjamini-Hochberg method. Immunoblotting was used to assess HER2 protein levels across a panel of bladder cancer cell lines. We then assessed cell viability and colony formation upon exposure to the specific ERBB2 inhibitor, tucatinib. Synergy between cisplatin and tucatinib in BLCA cell lines was evaluated using the Chou-Talalay method. In the TCGA BLCA dataset, HER2 protein positively correlates with ERBB2 signaling with a Pearson correlation coefficient of 0.45 and an adjusted p-value of 1.73E-17. ERBB2 signaling has multiple significant positive and negative correlations. ERBB2 signaling negatively correlates with the DNA repair gene set with a Pearson coefficient of -0.5 and an adjusted p-value of 1.40E-22. HER2 protein expression varies greatly between bladder cancer cell lines: HT-1197 and UMUC3 have lower HER2 expression, with HT-1376, T24, RT4, 5637, and SW780 showing higher HER2 expression. HT-1197 and RT4 had the lowest IC50s for tucatinib and showed a strong response to low doses of tucatinib in the colony formation assay. Cisplatin and tucatinib have synergetic growth inhibition (combination index <1) at low concentration levels in the HT-1197 and SW780 cell lines. Multiple oncogenic pathways coexist with ERBB2 signaling in BLCA. The varied response to specific ERBB2 inhibition and the lack of correlation of the response with HER2 protein level in cell lines alludes to alternative oncogenic pathways. A strong negative correlation of ERBB2 signaling with the DNA response pathway in the TCGA BLCA dataset, combined with preclinical evidence of synergy between tucatinib and cisplatin, indicates a potential for development of the combination as a clinical treatment strategy and warrants further study. Citation Format: Constance Caparas-Spaugy, Chris Stubben, Ken Boucher, Bingjian Feng, Aaron Atkinson, David Nix, Bradley Cairns, Sumati Gupta. ERBB2 signaling and inhibition in bladder cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4696.

Clinical characteristics and prognostic factors of breast cancer patients with tumor deposits in the ipsilateral axillary region

Objective: To investigate the clinicopathologic features and prognostic factors of breast cancer patients with tumor deposits in the ipsilateral axillary region. Methods: We retrospectively analyzed the clinicopathologic data and follow-up results of 155 patients with breast cancer diagnosed for the first time and complicated with tumor deposits in the ipsilateral axillary region in the Department of Thyroid-Breast-Vascular Surgery of Xijing Hospital from January 2008 to September 2018. Kaplan-Meier method was used for survival analysis. Log rank test was used for the univariate analysis of prognostic factors, and Cox regression was used for multivariate analysis. Results: The median disease free survival (DFS), median distant metastasis free survival (DMFS), and median overall survival (OS) of the 155 patients were 52.0 months, 66.6 months, and 102.2 months, respectively. The 5-year and 10-year DFS rates were 45.7% and 23.1%, the 5-year and 10-year DMFS rates were 56.9% and 28.9%, and the 5-year and 10-year OS rates were 79.3% and 46.0%, respectively. Multivariate Cox regression analysis showed that family tumor history (HR=0.362, 95% CI: 0.140-0.937), clinical T stage (T3: HR=3.508, 95% CI: 1.380-8.918; T4: HR=2.220, 95% CI: 1.076-4.580), estrogen/progesterone receptor status (HR=0.476, 95% CI: 0.261-0.866), number of tumor deposits (HR=1.965, 95% CI:1.104-3.500) and neoadjuvant chemotherapy (HR=1.961, 95% CI: 1.032-3.725) were independent influencing factors for DFS. Molecular subtype [human epidermal growth factor receptor-2(HER-2) positive and hormone receptor negative: HR=7.862, 95% CI: 3.189-19.379], number of tumor deposits (HR=2.155, 95% CI: 1.103-4.212), neoadjuvant chemotherapy (HR=5.002, 95% CI: 2.300-10.880) and radiotherapy (HR=2.316, 95% CI: 1.005-5.341) were independent influencing factors of DMFS. Histological grade (HR=4.362, 95% CI: 1.932-9.849), estrogen/progesterone receptor expression (HR=0.399, 95% CI: 0.168-0.945), HER-2 expression (HR=2.535, 95% CI: 1.114-5.768) and neoadjuvant chemotherapy (HR=4.080, 95% CI: 1.679-9.913) were independent influencing factors of OS. Conclusions: The presence of tumor deposits weakens the influence of axillary lymph node status and distant metastases on the prognosis of breast cancer patients. Therefore, a clinicopathological staging system taking into account tumor deposits should be developed. Since the number of tumor deposits affects the risk of recurrence and metastasis of breast cancer patients, we recommend that the number of tumor deposits should be reported in detail in the pathological report after breast cancer surgery.

Expression of HER2 in high-grade urothelial carcinoma based on Chinese expert consensus and the clinical effects of disitamab vedotin-tislelizumab combination therapy in the treatment of advanced patients.

Background: A vast number of researchers have discovered high levels of human epidermal growth factor receptor-2 (HER2) expression in urothelial carcinoma (UC), but they do not use a uniform scoring system. Based on the 2021 edition of clinical pathological expert consensus on HER-2 testing in UC in China, we investigated the expression level and clinical significance of HER2 in high-grade UC. Furthermore, we looked at the prognosis of patients with locally advanced/metastatic UC after combining HER2 targeting antibody-drug conjugates (ADC) medication disitamab vedotin (DV) with programmed cell death protein 1 (PD-1) inhibitor tislelizumab. Patients and methods: From 2019 to 2022, we collected paraffin specimens of UC from the Department of Urology at the Provincial Hospital Affiliated to Shandong First Medical University. HER2 expression-related factors were investigated. Patients with advanced UC who have failed systemic chemotherapy at least once and had received immune checkpoint inhibitor (ICI) medication during second-line treatment were selected and treated with DV in combination with tislelizumab. We assessed the therapy's efficacy and safety. Results: 185 patients with high-grade UC were included in this investigation. 127 patients (68.7%) were HER2 positive (IHC 2+/3+) according to the 2021 Clinical pathological expert consensus on HER2 testing in UC in China. The clinical stage of UC differed statistically significantly between the HER2-and HER2+ groups (p = 0.019). Sixteen advanced UC patients were treated with DV and tislelizumab for a median of 14months. The disease control rate was 87.5%, while the objective response rate (ORR) was 62.5%. The ORR of HER2+ individuals was higher than that of HER2-individuals (70.0% vs. 50.0%). The median progression-free survival or overall survival was not reached. In this study, the incidence of treatment-related adverse events was 68.8% (11/16), with all of them being grade 1 or 2 adverse reactions. Conclusion: HER2 protein expressed at a high percentage in UC, and 68.7% patients expressed HER2 positive (IHC 2+/3+). HER2+ expression is positively correlated with higher clinical stage of UC. HER2 targeted ADC drug disitamab vedotin combining with PD-1 inhibitor tislelizumab has shown efficacy, safety and controllable adverse reactions in the treatment of advanced UC.

Target-Oriented Classification of Triple-negative Breast Cancer.

Breast cancer that is estrogen receptor (ER)-negative, progesterone receptor (PR)-negative, and human epidermal growth factor receptor-2 (HER2)-negative is termed triple-negative breast cancer (TNBC). Cytotoxic chemotherapy remains the first choice of treatment against TNBC due to lack of specific therapeutic targets. TNBC is not classified based on therapeutic targets, but recently, the development of targeted therapies - including immune checkpoint inhibitors and poly (adenosine diphosphate-ribose) polymerase inhibitors - has gained attention. This study aimed to examine a novel target-oriented TNBC classification to further facilitate targeted therapy by classifying TNBC based on the breast cancer 1 (BRCA1)-like as well as the protein expression of HER2, programmed death ligand 1 (PD-L1), androgen receptor (AR), cytokeratin 5/6, and epidermal growth factor receptor (EGFR). We enrolled 17 patients with primary TNBC who did not receive preoperative chemotherapy and underwent surgery at the Kobe University Hospital, Japan, between January 1, 2018, and July 31, 2019. Immunohistochemical staining was performed on tumor specimens, while a BRCAness test was performed using multiplex ligation-dependent probe amplification (MLPA) analysis. A BRCAness score 0.5 or higher was considered BRCA1-like. Tumors were classified as HER2-low (immunohistochemistry score 1+ or 2+ and FISH negative), PD-L1 positive, AR positive, or BRCA1-like. HER2-low, PD-L1 positive, AR positive, and BRCA1-like were detected in 11 (64.7%), 4 (23.5%), 6 (35.3%), and 6 (35.3%) samples. The tumor of only one patient could not be classified into any of these categories. Almost all TNBC cases can be classified according to treatable targets.

Human Epidermal Growth Factor Receptor-2 Gastric Adenocarcinoma: Expanding Therapy of a Recognized Target.

Human epidermal growth factor receptor-2 (HER2) is a well-known cancer target. Many HER2-targeted agents are marketed and being investigated. Unfortunately, these therapies lack consistent responses and outcomes amongst different tumors. Questions remain as to why HER2 biology is different in different tumor types. Gastric adenocarcinomas (GACs) demonstrate both intra- and inter-tumor HER2 expression heterogeneity and show discordance amongst primary and metastatic disease sites. This creates barriers in determining HER2 agents' effectiveness and contributes to the failure of some HER2-targeted agents in the treatment of HER2-positive advanced GACs. Trastuzumab deruxtecan, an antibody drug conjugate of trastuzumab with a topoisomerase inhibitor, was recently approved for the treatment of refractory HER2-positive advanced GAC patients. There are exciting and newer therapies under investigation. Examining resistance patterns (both adaptive and acquired) along with establishing a better understanding of the intra- and inter-tumor heterogeneity is necessary to ensure successful progress. Here we review the current status of HER2-targeted therapy in GACs. We additionally review newer therapies under investigation and their potential role in HER2 GACs.

Prognostic impact of reduced HER2 protein expression in post-neoadjuvant therapy resection specimens: A single institution experience and review of the literature

BackgroundRetesting for Human epidermal growth factor receptor-2 (HER2) in post-neoadjuvant therapy resection is variable, and data is conflicting regarding the prognostic significance of changes in HER2 expression pre and post therapy. MethodsWe identified 104 patients with localized HER2 IHC 3+ breast cancer who received neoadjuvant trastuzumab(T)/pertuzumab(P) containing chemotherapy at Yale Cancer Center between 2012 and 2022. Patients were divided into 3 cohorts by response and HER2 IHC in the residual disease: Cohort 1 pathologic complete response (pCR), Cohort 2 pre-treatment IHC 3+/post treatment IHC 1+/2+, and Cohort 3 pre-treatment IHC 3+/post-treatment IHC 3+. Kaplan-Meier survival analysis was performed to assess recurrence free survival at 36 months. ResultsThe overall pCR rate was 62.5% (65/104), while 37.5% (39/104) of patients had residual disease (RD). Among patients with RD, 58.9% (23/39) remained IHC 3+ and 41.1% (16/39) had reduced HER2 expression IHC1+ or 2+. In patients with HER2 IHC 3+ RD, 26% (6/23) developed local recurrence or distant metastasis while none of patients with post NAT HER2 IHC 1+ or 2+ RD had relapse (p = 0.0309). In patients with pCR, 6.15% (4/65) had recurrence. Kaplan-Meier survival analysis revealed superior disease-free survival in patients with reduced HER2 IHC expression compared to those with remained IHC 3+ (log rank p = 0.004). ConclusionWe conclude that reduced HER2 expression by IHC following neoadjuvant treatment was associated with lower recurrence rates in HER2 IHC 3+ breast cancer. If confirmed, RD HER2 IHC expression could be used as a prognostic biomarker to stratify patients in adjuvant trials and identify patients who may benefit from more intensive adjuvant therapy and post therapy surveillance.

Cellular analyses for label-free and rapid HER2-positive cancer diagnosis based on SPRi-modified with nanobody

Overexpression of human epidermal growth factor receptor-2 (HER2) is an important prognostic indicator for clinical diagnosis, as it results in more invasive cancer cells and lower survival rates. In this study, we developed a novel immunosensor based on surface plasmon resonance imaging (SPRi) modified with nanobody 2 (NB2) to detect the HER2 expression of various cancer cells. Firstly, we established a multi-channel intensity interrogation SPRi system with a refractive index resolution (RIR) of 1 × 10−6 RIU. Then, we fabricated the immunosensor by immobilizing NB2 nanobody on the sensor chip through affinity-based orientation. The NB2 exhibited high specificity for HER2 extracellular domain, enabling specific capture of HER2-positive cancer cells. The results revealed that the sensor could detect the HER2 expression of various living cancer cells by directly injecting cell suspensions. Compared with flow cytometry, SPRi system could obtain similar HER2 expression results with better performance, such as faster response time (<30 min), smaller sample volume (<200 μL), and lower cell concentration (105 cells/mL). The most important of all is that researchers do not need to take complex fluorescent labeling pretreatment of cell samples. Therefore, such immunosensors may offer great potential for rapid personalized treatment planning and enhanced patient outcomes.

PET/CT and SPECT/CT Imaging of HER2-Positive Breast Cancer.

HER2 (Human Epidermal Growth Factor Receptor 2)-positive breast cancer is characterized by amplification of the HER2 gene and is associated with more aggressive tumor growth, increased risk of metastasis, and poorer prognosis when compared to other subtypes of breast cancer. HER2 expression is therefore a critical tumor feature that can be used to diagnose and treat breast cancer. Moving forward, advances in HER2 in vivo imaging, involving the use of techniques such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT), may allow for a greater role for HER2 status in guiding the management of breast cancer patients. This will apply both to patients who are HER2-positive and those who have limited-to-minimal immunohistochemical HER2 expression (HER2-low), with imaging ultimately helping clinicians determine the size and location of tumors. Additionally, PET and SPECT could help evaluate effectiveness of HER2-targeted therapies, such as trastuzumab or pertuzumab for HER2-positive cancers, and specially modified antibody drug conjugates (ADC), such as trastuzumab-deruxtecan, for HER2-low variants. This review will explore the current and future role of HER2 imaging in personalizing the care of patients diagnosed with breast cancer.

The diagnostic value of BI-RADS grade 3 to 5 for breast masses is correlated with the expression of estrogen receptor, progesterone receptor, human epidermal growth factor receptor-2.

The breast imaging-reporting and data system (BI-RADS) grading has a great advantage in diagnosing breast diseases, but with some limitations. The study analyzed the value of ultrasound-guided core needle biopsy (CNB) in diagnosing BI-RADS grades 3, 4, and 5 breast cancer. Breast cancer patients at BI-RADS grades 3 to 5 received breast ultrasonography, ultrasound-guided CNB and immunohistochemical examination. Receiver operating characteristic (ROC) curve was made to test diagnostic efficiency of regression model. Calcification was positively correlated with expression of estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor (HER)-2. The areas of 4 ROC curves were 0.752, 0.805, 0.758, and 0.847, and the 95%CI was 0.660 to 0.844, 0.723 to 0.887, 0.667 to 0.849, and 0.776 to 0.918, respectively. BI-RADS grades 3 to 5 were positively correlated with expression of ER, PR and human epidermal growth factor receptor-2 (HER-2). Statistical significance existed between grade 5 and expression of ER, PR and HER-2, and between grade 4 and expression of HER-2. The study demonstrates that BI-RADS can be used as an effective evaluation method in the diagnosis of breast diseases before invasive operation, and it has higher diagnostic accuracy if combined with pathological examinations.

Clinical efficacy analysis of patients (pts) with HER-2 expressing metastatic urothelial carcinoma (mUC) treated with enfortumab vedotin (EV).

e16618 Background: EV, an antibody drug conjugate (ADC) targeting NECTIN-4, is an approved salvage treatment for unselected pts with mUC. ADCs targeting the human epidermal growth factor receptor-2 (HER-2) have also shown robust activity in clinical trials for mUC with tumor HER-2 expression. We investigated the interaction between HER-2 expression and clinical outcomes of pts treated with EV, which are currently unknown. Methods: We conducted a retrospective, single institution study analyzing pts with mUC who received EV. Immunohistochemistry (IHC) staining for HER-2 was completed with PATHWAY anti-HER2 (4B5) Antibody (Ventana Medical Systems, Tucson, AZ) using established breast cancer scoring algorithm. Wilcoxon rank sum and Fisher exact tests were used to compare continuous and categorical variables, respectively. Cox proportional hazards regression model was used to evaluate a variable’s ability to predict overall survival (OS). Variables with p-value ≤0.1 were included in the multivariate analysis (MVA). Results: We identified 158 pts with mUC who received EV. Median age at EV start was 70 (IQR 66-76), most pts were Caucasian (144, 91%), male (108, 68%), primary bladder tumors (113, 72%), and pure urothelial histology (95, 60%). 96 pts (61%) received prior platinum therapy and 117 pts (74%) had prior immunotherapy. ECOG scores ≥2 was seen in 54 pts (39%) while 75 pts (54%) had Bellmunt scores ≥2 (54%). Median follow up time was 12.5 months and median OS from EV start was 13 months. 94 pts (60%) had HER2 IHC staining. There was no association between HER2 intensity and any of the clinical variables. On univariate analysis (UVA): HER2 3 vs HER2 ≤2 HR was 0.38 (0.14, 0.98), male vs female HR=1.56 (0.94, 2.58), ECOG ≤1 vs ≥2 HR=0.6 (0.38,0.95), Bellmunt score 0-1 vs 2-3 HR=0.49 (0.3, 0.78), and hemoglobin (Hgb) HR=0.75 (0.67, 0.85). MVA showed HER2 3 vs HER2 ≤2 HR was 0.42 (0.16, 1.12), male vs female HR=2.3 (1.17, 4.42), ECOG ≤1 vs ≥2 HR=0.56 (0.30, 1.05), and Hgb HR=0.77 (0.65, 0.92). Conclusions: MVA of this single-site retrospective cohort did not show any association between HER2 expression and survival outcomes in pts with mUC who received EV. Further studies are needed to continue assessing the role of HER2 as a potential prognostic and predictive biomarker in UC, especially if HER-2 directed therapies become incorporated in the mUC treatment paradigm. [Table: see text]

Decreased HER2 expression in residual disease following neoadjuvant therapy in patients with HER2-positive breast cancer.

e12621 Background: Human epidermal growth factor receptor-2 (HER2) overexpression is a defining feature of roughly 20% of localized breast cancer and represents a critical target for therapy. Since the demonstration that residual disease (RD) after neo adjuvant therapy (NAT) is associated with worse prognosis and that adjuvant ado trastuzumab emtansine (tDM1) improves survival, NAT has become the standard of care for localized HER2+ breast cancer. Retesting for HER2 overexpression post resection is variable, and data is conflicting regarding the prognostic significance of changes in HER2 expression pre and post therapy. The objective of this study was to evaluate the association of pre and post neo adjuvant therapy HER2 immunohistochemistry (IHC) expression on breast cancer outcomes in our institutional database. Methods: After IRB approval, data was gathered for patients with localized HER2+ breast cancer receiving NAT including trastuzumab/pertuzumab at Yale Cancer Center between 2012 and 2022. Pathologic complete response (pCR) was defined as no residual invasive tumor in breast and lymph nodes. Patients were divided into 3 cohorts by response and HER2 IHC: Cohort 1 pCR Cohort 2 pre-treatment 3+/post treatment 1-2+, and Cohort 3 pre-treatment 3+/post treatment 3+. A Kaplan-Meier survival analysis was done to assess recurrence free survival at 36 months. Results: Within the specified time interval, we identified 104 patients with localized HER2-IHC 3+ breast cancer who received neoadjuvant therapy. The pCR rate was 62.5% (65/104), while 37.5% (39/104) of patients had RD. Among patients with RD, 58.9% (23/39) remained HER2 IHC 3+ and 41% (16/39) had decreased HER2 expression IHC1+/IHC 2+. Median follow-up was 27.9 months at time of analysis. In patients with HER2 3+ RD 26% (6/23) developed local recurrence or distant metastasis while none of patients with HER2 IHC 1+ or 2+ RD had relapse ( p= 0.0309). In patients with pCR, 6.15% (4/65) had recurrence. Kaplan-Meier survival analysis showed a significant difference between the 3 groups (log rank p= 0.004). Conclusions: In our retrospective cohort, decreased HER2 expression by IHC following neoadjuvant treatment was associated with lower recurrence rates. If confirmed, RD HER2 IHC expression could be used as a prognostic biomarker to select patients for more or less aggressive adjuvant therapy, stratify patients in adjuvant trials, and identify patients who may benefit from more intensive post therapy surveillance.

HER2-low breast cancer brain metastases: Incidence and treatment implications.

2035 Background: Brain metastases (BrM) are a major cause of morbidity and mortality among women with breast cancer (BC). Central nervous system (CNS)-penetrating systemic therapies for patients with HER2-negative BrM are lacking; this is particularly problematic for patients with triple negative disease (TNBC) who have a high likelihood of developing BrM. Given CNS activity of trastuzumab deruxtecan, efficacy for patients with HER2-low BrM is of interest. Methods: A retrospective study of two cohorts of patients who underwent surgery for BC BrM at Sunnybrook Health Sciences Centre between 1999-2013 and 2008-2018 were identified. Estrogen receptor, progesterone receptor, and human epidermal growth factor receptor-2 (HER2) status were assessed based on 2018 ASCO/CAP guidelines. HER2-zero was defined as immunohistochemistry (IHC) 0; HER2-low was defined as IHC 1+ or IHC 2+ with fluorescence in situ hybridization (FISH) negative status. HER2-positive was defined as IHC 3+ or IHC 2+ with positive FISH. Clinicopathological features were recorded. We also assessed the prognostic association between extent of HER2 expression and i) brain-specific progression free survival (bsPFS), as well as ii) overall survival (OS). Results: Out of 137 patients with resected BrM, tissue for HER2 assessment was available in 74.5% (n=102) of cases. In this cohort, the median age at BrM diagnosis was 53.5 (range, 32-85). 18.6% (n=19) had leptomeningeal disease and 68.6% (n=70) had extracranial disease. 53% (n=54) of the BrM were HER2-positive; 29.4% (n=30) were HER2-low and 17.6% (n=18) had HER2-zero status. Among BrM that were triple negative based on ASCO/CAP guidelines, 14 out of 22 cases (63.6%) were re-classified as being HER2-low. 15/25 (60%) BrM that were hormone receptor positive/HER2 negative (HR+/HER2-) based on ASCO/CAP guidelines were re-classified as being HER2-low. In total, 51 patients had matched primary breast and BrM tissue available; results of HER2 status when categorized as HER2-zero, HER2-low and HER2-positive were concordant in 82.3% (n= 42/51) of cases (Cohen’s kappa 0.58, p=0.0719). In 7 cases, the primary breast tissue was HER2-zero whereas the BrM was either HER2-low (n=5) or HER2-positive (n=2). In only one case (2%), expression of HER2 was lower in the BrM (HER2-low) compared to the primary BC (HER2-positive). Median time from primary BC to the development of BrM was 35 months (IQR, 14-69) in the overall cohort; patients with HER2-zero BrM had a numerically longer time to development of BrM (45.8 months), compared to those with HER2-low (35 months) and HER2-positive (35 months) BrM (p=0.948). There was no significant association between HER2-zero, HER2-low and HER2-positive status in BrM and either bsPFS or OS. Conclusions: Among patients with surgically resected BrM, a high proportion of those with metastatic TNBC and HR+/HER2-negative disease have “HER2-low” BrM with potential to benefit from HER2-targeted therapy.

Differences in treatment outcomes in relation to level of human epidermal growth factor receptor-2 (HER2) expression, HER2-low vs HER2-zero, in patients with hormone receptor-positive metastatic breast cancer treated with cyclin dependent kinase CDK4/6 inhibitors: A systematic review and meta-analysis.

e13081 Background: Patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancers (MBC) are usually treated with endocrine therapy (ET) in combination with cyclin dependent kinase (CDK4/6) inhibitors. Such combinations have significantly improved treatment outcomes. HER2-negative MBC have recently been divided into two subgroups: HER2-zero, with an immunohistochemistry (IHC) score of 0, and HER2-low, with an IHC score of 1+ or 2+ and a negative in situ hybridization (ISH) assay. The aim of this meta-analysis is to compare treatment outcomes of these two groups of MBC patients when treated with a combination of ET and CDK4/6 inhibitors. Methods: A systematic literature review was conducted to identify relevant studies on the level of HER2 expression in breast cancer patients treated with CDK4/6 inhibitors. The review included articles in databases such as Medline via PubMed, Embase, and Cochran Library, as well as abstracts from the ASCO meeting and SABCS conference updated tell January 2023. Eligible studies included randomized controlled trials, prospective or retrospective studies, and case-control studies that compared the difference in PFS between HER2-low and HER2-zero among breast cancer patients treated with CDK4/6 inhibitors in first-line or beyond setting. A meta-analysis was performed to determine the pooled hazard ratio for progression-free survival (PFS). In addition, a pooled survival curve was created by digitizing the Kaplan-Meier curves to create pseudo-individual patients’ data following the methodology outlined by Combescure et. al (2014). Results: In total, 7 different studies were identified that included a total of 1,341 patients. The random effect model shows a statically significant shorter PFS in the HER2-low group; 17.2 months compared to 24.0 months in HER2-zero group (HR=1.55; 95% CI [1.27-1.84]; p &lt;0.001). There was no statically significant heterogeneity between the studies (I2=51% p-value=0.07). The PFS rates at 12, 24, 36, and 48 months for HER2-low were as follow: (66.2%; 95% CI [50.0%-87.5%]), (33.2 %; 95% CI= 17.4%-63.4%), (26.2%; 95% CI= 12.8%-53.38%), and (22.05%; CI95%= 10.32%-47.12%), respectively compared to: (77.73%; 95% CI= 64.45%-93.75%), (50.00%; 95% CI= 34.66%-72.13%),(43.58%; 95% CI= 22.91%-82.89%), and (36.85%; 95% CI= 17.60%-77.15%) among patients with HER2-zero. Conclusions: In patients with MBC treated with CDK4/6 inhibitors, level of HER2 negativity may affect treatment outcomes; patients with HER2-zero had better PFS compared to those with HER2-low disease. Such findings, if confirmed in larger studies, may change the landscape of treatment of this group of patients.

Abstract 967: Real-world transcriptomic biomarkers as replacement for immunohistochemistry and FISH studies in breast cancer

Abstract Background: Human epidermal growth factor receptor-2 (HER2) and hormone receptors are typically used as binary biomarkers for selecting breast cancer therapy. There is a need to explore the clinical relevance of these biomarkers as continuous variables. This is particularly relevant for the new class of antibody-drug conjugates (ADC), in which a relatively low HER2 expression level is adequate for targeting tumor cells. We explored the potential of RNA profiling, determined by next generation sequencing (NGS), to provide more flexible clinical biomarkers as compared with immunohistochemistry (IHC) or fluorescent in situ hybridization (FISH). Methods: Clinical and laboratory data from 57 breast cancers collected by the COTA real-world data company were used to study biomarker levels as detected by routine clinical transcriptomic tests. HER2 (ERBB2), estrogen receptor alpha (ESR1), and androgen receptor (AR) mRNA levels were compared with reported HER2 and estrogen receptor (ER) IHC and FISH results. Results: RNA levels accurately reflected and predicted HER2 amplification (see table below). Importantly, RNA data showed significant variation and overlap in the levels of ERBB2 mRNA between cases scored by IHC as zero, 1+, and 2+. This variation correlated with progression-free survival (PFS). Similarly, the ESR1 RNA levels accurately reflected ER status and demonstrated significant variation between positive cases. RNA data also showed significant variations in the AR levels. Patients wssith high AR mRNA levels had significantly better PFS (P=0.05). Patients expressing high ER and AR levels had significantly better PFS than those expressing low ESR1 and AR levels (P=0.03). Conclusions: These findings suggest that RNA analysis using NGS is an alternative to IHC and FISH. RNA provides continuous data that can determine cut-off points predicting response to therapy and should be explored in predicting ADC response. ERBB2 mRNA levels (FPKM) in various HER2 IHC groupss IHC Score Valid N Mean Median Minimum Maximum Quartile Range Std.Dev. Zero 19 231 243 63 537 170 110 Zero vs one 3 151 155 45 253 208 104 Zero to one vs one 18 397 302 172 845 365 222 One Vs two 13 495 423 159 1094 273 284 Two vs three 4 7523 7649 937 13859 7183 5310 Citation Format: Maher Albitar, Andre Goy, Andrew Pecora, Deena Graham, Donna Donna McNamara, Ahmad Ahmad Charifa, Andrew IP, Wanlong Ma, Stanley Waintraub. Real-world transcriptomic biomarkers as replacement for immunohistochemistry and FISH studies in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 967.

Abstract P4-07-33: Differences in Treatment Outcomes Between Patients with HER2-Low versus HER2-Zero, Hormone Receptor-Positive Advanced-Stage Breast Cancer Treated with CDK4/6 Inhibitors

Abstract Background: The cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors transformed the care of patients with hormone receptor-positive (HR+), human epidermal growth factor receptor-2 (HER2)-negative (HR+/HER2−) advanced-stage breast cancer (aBC). Breast cancers with no expression of HER2 are recently classified into two groups: HER2-Zero subtype which include those with HER2-immunohistochemistry (IHC) score of 0 (IHC-0) and “HER2-low”, defined as HER2-IHC score of 1+ or (2+ with negative in situ hybridization (ISH) assay). There is increasing interest in the HER2-low subtype which is becoming a new distinct entity with promising data from recently reported clinical trials using novel anti-HER2 antibody-drug conjugates (ADC) in this subgroup. This study investigates the differences in treatment outcomes between patients with aBC with HER2-low versus those with HER2-Zero (IHC-0) disease treated with CDK4/6 inhibitors and endocrine therapy (ET). Methods: We retrospectively reviewed patients with (HR+/HER2−) aBC who received CDK4/6 inhibitors with an aromatase inhibitor (AI) or fulvestrant from June 2017 to May 2020 at a single cancer center. Data was extracted from patients’ electronic medical records and from our institutional cancer registry. Progression-free survival (PFS), defined as the time from the initiation of CDK4/6 inhibitors to the date of radiological or clinical progression or death, and was estimated by the Kaplan-Meier method and compared by the log-rank test. Multivariate Cox regression modeling was performed with covariates including progesterone receptor (PR) status, prior chemotherapy, site of metastasis (visceral versus bone-only disease), line of treatment (first-line or beyond), menopausal status, age (less than or ≥ 45) and number of metastatic sites (&amp;lt; or ≥ 3). P-value &amp;lt; 0.05 was considered statistically significant. Results: During the study period, a total of 256 patients with advanced-stage breast cancer who received ET and CDK4/6 inhibitors (ribociclib in all patients) were included, median age was 48 (22-87) years. Majority (n=162, 63.3%) received ribociclib as a first-line therapy while the others had it as a second line and beyond. 136 (53.1%) patients had de novo metastatic disease, and 122 (47.7%) were premenopausal. In total, 114 (44.5%) of the patients where HER2-Zero (IHC-0), while 142 (55.5%) others had HER2-low disease as defined above. The overall response rate (ORR) for the HER2-Zero group was 52% versus 39% for the HER2-low group (P= 0.005).The median PFS was 23.0 (95% confidence interval [CI], 19-40) months for HER2-Zero versus 17.0 (95% CI 14-20,) months for HER2-low; P= 0.0035. In multivariate analysis, HER2-low expression remained significant determinant of inferior PFS after adjusting for other factors including the line of treatment (aHR:2.10, 95% CI 1.03-4.27, P=0.041), age (aHR 2.20, 95% CI 1.29-3.77, P=0.004)), number of metastasis (aHR:1.96, 95% CI 1.32-2.91, P=0.001), and site of metastasis (aHR:1.64, 95%CI 1.058-2.55, P=0.027). Conclusion: In patients with advanced-stage breast cancer treated with CDK4/6 inhibitors and ET, level of HER2 negativity may affect treatment outcomes; patients with HER2-Zero had better PFS compared to those with HER2-low disease. These findings, if confirmed in larger studies, should help oncologists select patients with HER2-low for better treatment options including a combination of anti-HER2 therapy and CDK4/6 inhibitors. Citation Format: Baha’ Sharaf, Hala Abu-Fares, Faris Tamimi, Suhaib Al-Sawajneh, Osama Salama, Rand Daoud, Abdulrahman A. Alhajahjeh, Sawsan Al-lababidi, Hikmat Abdel-Razeq. Differences in Treatment Outcomes Between Patients with HER2-Low versus HER2-Zero, Hormone Receptor-Positive Advanced-Stage Breast Cancer Treated with CDK4/6 Inhibitors [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-07-33.

The role of claudin 18.2 and HER-2 in pancreatic cancer outcomes.

To examine the prognostic value of claudin 18.2 (CLDN18.2) and human epidermal growth factor receptor-2 (HER-2) expression in patients with resected pancreatic ductal adenocarcinoma (PDAC). This study enrolled patients who underwent surgery and were diagnosed with PDAC at Suleyman Demirel University Hospital, Turkey between 2015 and 2019. Sixty-eight patients with resected PDAC treated at a medical oncology clinic were assessed. All patients were over the age of 18 years, underwent follow-up and treatment in our unit, and had pathology slides that we could access. Clinicopathological data were obtained from medical files, including the patients' age, sex, pathological parameters, and clinical stage according to the Eighth International Union against Cancer/American Joint Committee on Cancer. Patient survival and the period from the date of diagnosis to death were assessed in the follow-up data. There was no statistically significant difference between CLDN18.2 and HER-2 expression scores for samples and patient clinicopathological characteristics. No HER-2 expression scores of ≥2 were found in the samples. Only 25% (n = 17) of the samples had HER-2 expression scores of +1. CLDN18.2 expression was detected in 54.4% (n = 37) of the patient samples. CLDN18.2 expression scores were +1 in 30.8% (n = 21) of the patient samples, +2 in 16.2% (n = 11), and +3 in 7.4% (n = 5). When CLDN18.2 and HER-2 expression were compared, a statistically significant difference and moderate positive correlation were observed. No significant relationship between HER-2 expression and survival was observed in the survival analysis of PDAC patients; however, high CLDN18.2 expression was related to longer overall survival. Our study is the third to research CLDN18.2 expression in PDAC. HER-2 expression is low and CLDN18.2 expression is high in patients with PDAC. HER-2 expression is not related to overall survival but CLDN18.2 is related and may be used as a prognostic marker in patients with PDAC.