HER2 Expression Research Articles

Clinical characterization, prognostic, and predictive values of HER2-low in patients with early breast cancer in the PALLAS trial (ABCSG-42/AFT-05/BIG-14–13/PrE0109)

BackgroundBidirectional crosstalk between HER2 and estrogen receptor (ER) pathways may influence outcomes and the efficacy of endocrine therapy (ET). Low HER2 expression levels (HER2-low) have emerged as a predictive biomarker in patients with breast cancer (BC).MethodsPALLAS is an open, international, phase 3 study evaluating the addition of palbociclib for 2 years to adjuvant ET in patients with stage II-III ER-positive/HER2-negative BC. To assess the impact of HER2 expression on patient outcomes in the phase III PALLAS trial, we analyzed (1) the association between rate of HER2-low with demographic and clinicopathological parameters, (2) the prognostic value of HER2-low status on invasive disease-free survival (iDFS), distant relapse-free survival (DRFS), and overall survival (OS) and (3) HER2 expression’s value as a predictive biomarker of response to palbociclib. HER2-low was defined as HER2 immunohistochemistry (IHC) 1 + or IHC 2 + with negative in situ hybridization (ISH). All pathologic evaluation was performed locally. Prognostic and predictive power of HER2 were assessed with Cox models.ResultsFrom the original PALLAS intention-to-treat population (N = 5753), 5304 patients (92.2%) were included in this analysis. Among these, 2254 patients (42.5%) were classified as having HER2 IHC 0 (HER2-0), and 3050 (57.5%) as having HER2-low disease (1838 with IHC 1 + and 1212 with IHC 2 +). Median follow-up was 59.8 months. HER2-low prevalence varied significantly across 21 participating countries (range 16.7% to 75.6%; p < 0.001) and was more frequent in patients enrolled in North America (63.1%) than in Europe (53.4%) or other regions (53.4%) (p < 0.001). HER2 status was not significantly associated with iDFS in a multivariable Cox model (hazard ratio 0.93, 95% confidence interval 0.81 – 1.06). No significant interaction was observed between treatment arm and HER2 status for iDFS (p = 0.43). Similar results were obtained for DRFS and OS.ConclusionsIn this large, prospective, global patient cohort, no differences were observed in clinical parameters, prognosis, or differential benefit from palbociclib between HER2-0 and HER2-low tumors. Significant geographic variability was observed in the prevalence of HER2-low status, suggesting a high degree of variation in pathologic assessment of HER2 expression without impact on outcomes.

Impact of low HER2 expression on response to CDK4/6 inhibitor treatment in advanced HR + /HER2- breast cancer: a multicenter real-world data analysis.

CDK4/6 inhibitors (CDK4/6i) represent the first-line therapy approach of choice for patients with hormone receptor-positive, HER2-negative advanced breast cancer (HR + /HER-ABC). Approximately 50% of HR + /HER2-ABC displays low HER2 expression (HER2 low). Recent data emerging from the DESTINY-Breast04 trial demonstrated practice-changing efficacy of the antibody-drug conjugate trastuzumab deruxtecan (T-DXd) in patients with low HER2 expression. Here, we aimed to analyze the impact of low HER2 expression on CDK4/6i therapy response in a well-characterized multicenter HR + /HER-ABC cohort. Patients diagnosed with HR + /HER2-ABC who were treated with CDK4/6i in clinical routine between November 2016 and December 2020 at four certified German Breast Cancer Centers were retrospectively identified. The cohort was stratified according to graduation of positivity in HER2 immunohistochemistry (IHC; HER2 zero = IHC score 0 and HER2 low = IHC score 1 + , 2 + /fluorescence in situ hybridization negative). Subgroups were analyzed with regard to progression-free survival (PFS) following CDK4/6i initiation. The study cohort comprised n = 448 patients. For n = 311 patients, HER2 status from the metastatic site was available. n = 91 (29.3%) cases were HER2 zero and n = 220 cases (70.7%) were HER2 low. There was no significant difference in PFS between the two groups (PFS: 17months versus 18months, log-rank p = 0.42). Further, we examined the influence of HER2 expression changes between primary and metastatic tissue (n = 171; HER2 gain/HER2 loss/HER2 stable expression) on CDK4/6i treatment response. Again, there was no significant difference between these three groups, respectively (PFS: 16months versus 13months versus 17months, log-rank p = 0.86). In our analysis, HER2 status did not have a significant impact on treatment response to CDK4/6i.

Macrophages: Key Players in the Battle against Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a challenging subtype of breast cancer characterized by the absence of estrogen and progesterone receptors and HER2 expression, leading to limited treatment options and a poorer prognosis. TNBC is particularly prevalent in premenopausal African-descent women and is associated with aggressive tumor behavior and higher metastatic potential. Tumor-associated macrophages (TAMs) are abundantly present within the TNBC microenvironment and play pivotal roles in promoting tumor growth, progression, and metastasis through various mechanisms, including immune suppression and enhancement of angiogenesis. This review provides an in-depth overview of TNBC, focusing on its epidemiology, its molecular characteristics, and the critical influence of TAMs. It discusses the pathological and molecular aspects that define TNBC’s aggressive nature and reviews current and emerging therapeutic strategies aimed at targeting these dynamics. Special attention is given to the role of TAMs, exploring their potential as therapeutic targets due to their significant impact on tumor behavior and patient outcomes. This review aims to highlight the complexities of the TNBC landscape and to present the innovative approaches that are currently being pursued to improve therapeutic efficacy and patient survival.

P1.06B.16 HER3 Expression Across Genomic Subsets of NSCLC

P1.06B.16 HER3 Expression Across Genomic Subsets of NSCLC

MO25-1 Evaluation of HER2 expression across various solid tumors in Vietnamese patients: a large-scale study

MO25-1 Evaluation of HER2 expression across various solid tumors in Vietnamese patients: a large-scale study

206 (PB194): Tailoring the Diagnostic Pathway in Patients with Gastric Cancer (GC) Using the Innovative inPROBE® Technology Platform to Assess HER2 Expression in Peritoneal Lavage: A Pilot Study

206 (PB194): Tailoring the Diagnostic Pathway in Patients with Gastric Cancer (GC) Using the Innovative inPROBE® Technology Platform to Assess HER2 Expression in Peritoneal Lavage: A Pilot Study

EGFR-directed antibodies promote HER2 ADC internalization and efficacy.

Trastuzumab deruxtecan (T-DXd) is a human epidermal growth factor receptor 2 (HER2)-targeting antibody drug conjugate that has remarkable activity in HER2-positive cancers. However, the degree of benefit of T-DXd is not uniform among solid tumors even with high levels of HER2. Despite high HER2 expression, the HER2/T-DXd complex may not always undergo internalization and payload release dependent on the receptor's conformation and context. We hypothesize that epidermal growth factor receptor (EGFR), a dimerization partner of HER2, can modulate HER2 trafficking through endocytic pathways and affect T-DXd uptake. We demonstrate that elevated EGFR expression levels can promote EGFR/HER2 heterodimer formation and suppress T-DXd internalization and efficacy. Knockdown of EGFR expression or pharmacologic stimulation of EGFR endocytosis with EGFR monoclonal antibodies restores T-DXd trafficking and antitumor activity in EGFR-overexpressing cancers invivo. Our results reveal EGFR overexpression to be a potential mechanism of resistance to T-DXd, which can be overcome by combination therapy strategies targeting EGFR.

MO19-3 Comparison of HER2 expression status between conventional HER2 test and VENTANA HER2 (4B5) of metastatic breast cancer

MO19-3 Comparison of HER2 expression status between conventional HER2 test and VENTANA HER2 (4B5) of metastatic breast cancer

Potential Use of Extracellular Vesicles for the HER2 Status Assessment in Breast Cancer Patients.

Human epithelial growth factor receptor 2 (HER2)-targeted therapies are effective in patients with HER2-positive breast cancer. Recent advances have shown that HER2-targeted therapies can also be of benefit when treating tumors expressing low levels of HER2, highlighting the importance of identifying the HER2-low subgroup. This clinical trend has opened new therapeutic avenues for patients who were previously ineligible for HER2-targeted therapies. Thus, the development of new diagnostic methods for real-time HER2 profiling is crucial for accurately tailoring the treatment for these patients. We hypothesized that tumor-derived extracellular vesicles (TEVs) could reflect the HER2 profiles of primary tumors and potentially serve as diagnostic tools for HER2 status. This approach was validated using six breast cancer cell lines, which confirmed that the TEVs accurately reflected the HER2 profiles of the tumor cells. TEVs were isolated using an immunoaffinity method, and copy number variation (CNV) in the ERBB2/EIF2C ratio was assessed using droplet digital PCR of DNA from these vesicles. Clinical validation using plasma samples from 33 breast cancer patients further reinforced the diagnostic potential of our method. Pearson's correlation coefficient analysis of the flow cytometry results demonstrated that TEVs reflected HER2 expression in primary cells. To distinguish between HER2-negative and HER2-low patients, the area under the curve (AUC) of the ROC curve in our method was 0.796, with a sensitivity of 53.8% and a specificity of 100%. These findings suggest the clinical utility of extracellular vesicles derived from plasma and emphasize the need for further research to distinguish HER2-negative from HER2-low patients.

Precision HER2: a comprehensive AI system for accurate and consistent evaluation of HER2 expression in invasive breast Cancer

BackgroundWith the development of novel anti-HER2 targeted drugs, such as ADCs, it has become increasingly important to accurately interpret HER2 expression in breast cancer. Previous studies have demonstrated high intra-observer and inter-observer variabilities in evaluating HER2 staining by human eyes. There exists a strong requirement to develop artificial intelligence (AI) systems to achieve high-precision HER2 expression scoring for better clinical therapy.MethodsIn the present study, we collected breast cancer tissue samples and stained consecutive sections with anti-Calponin and anti-HER2 antibodies. High-quality digital images were selected from immunohistochemical slides and interpreted as HER2 3+, 2+, 1+, and 0. AI models were trained and assessed using annotated training and testing sets. The AI model was trained to automatically identify ductal carcinoma in situ (DCIS) by Calponin staining and myoepithelial annotation and filter out DCIS components in HER2-stained slides using image-overlapping techniques. Furthermore, we organized two-phase validation studies. In phase one, pathologists interpreted 112 HER2 whole-slide images (WSIs) without AI assistance, whereas in phase two, pathologists read the same slides using the AI system after a washing period of 2 weeks.ResultsOur AI model greatly improved the accuracy of reading (0.902 vs. 0.710). The number of HER2 1 + patients misdiagnosed as HER2 0 was significantly reduced (32/279 vs. 65/279), and they benefitted from ADC drugs. In addition, the AI algorithm improved the intra-group consistency of HER2 readings by pathologists with different years of experience (intra-class correlation coefficient [ICC]: 0.872–0.926 vs. 0.818–0.908), with the improvement most pronounced among junior pathologists (0.885 vs. 0.818).ConclusionsWe proposed a high-precision AI system to identify and filter out DCIS components and automatically evaluate HER2 expression in invasive breast cancer.

Comparison of clinicopathological characteristics, efficacy of neoadjuvant therapy, and prognosis in HER2-low and HER2-ultralow breast cancer

BackgroundThis study aims to analyze potential differences in clinicopathology, efficacy of neoadjuvant therapy (NAT), and clinical outcome among HER2-null, HER2-ultralow and HER2-low breast cancers.MethodsConsecutive cases of HER2-negative breast cancer that received NAT were included. They were classified as HER2-null (no staining), HER2-ultralow (incomplete faint staining in ≤ 10% of tumour cells) and HER2-low (HER2-1 + or HER2-2+, in situ hybridisation negative). Subgroup analysis was performed based on the HER2 expression level.ResultsOut of 302 patients, 215 (71.19%) were HER2-low, 59 (19.54%) were HER2-ultralow, and 28 (9.27%) were HER2-null. In comparison to the HER2-ultralow group, the HER2-low group exhibited higher expression frequencies of ER (p < 0.001), PR (p < 0.001), and AR (p = 0.004), along with a greater prevalence of the luminal subtype (p < 0.001). The HER2-ultralow group also demonstrated a higher prevalence of lymph node metastasis compared to the HER2-null group (p = 0.026). Varied rates of pathologic complete response (pCR) were observed among the three subgroups: HER2-null, HER2-ultralow, and HER2-low, with rates of 35.71%, 22.03%, and 12.56%, respectively. Only the HER2-low subgroup exhibited a significant difference compared to HER2-null (p = 0.001). Despite variations in pCR rates, the three subgroups exhibited comparable disease-free survival (DFS) (p = 0.571). Importantly, we found HER2-low patients with better treatment response (RCB-0/I) exhibited significantly better DFS than those with significant residual disease (RCB-II/III) (P = 0.036). The overall rate of HER2 immunohistochemical score discordance was 45.24%, mostly driven by the conversion between HER2-0 and HER2-low phenotype. Notably, 32.19% of cases initially classified as HER2-0 phenotype on baseline biopsy were later reclassified as HER2-low after neoadjuvant therapy, and it is noteworthy that 22 out of these cases (78.57%) originally had an HER2-ultralow status in the pretreatment biopsy sample.ConclusionsOur results demonstrate the distinct clinicopathological features of HER2-low and HER2-ultralow breast tumors and confirm that RCB is an effective predictor of prognosis in HER2-low populations for the first time. Notably, our findings demonstrate high instability in both HER2-low and HER2-ultralow expression from the primary baseline biopsy to residual disease after NAT. Furthermore, this study is the first to investigate the clinicopathological feature and the effectiveness of NAT for HER2-ultralow breast cancer.

Preoperative Prediction of Her-2 and Ki-67 Status in Gastric Cancer Using 18F-FDG PET/CT Radiomics Features of Visceral Adipose Tissue.

Aims/Background Immunohistochemistry (IHC) is the main method to detect human epidermal growth factor receptor 2 (Her-2) and Ki-67 expression levels. However, IHC is invasive and cannot reflect their expression status in real-time. This study aimed to build radiomics models based on visceral adipose tissue (VAT)'s 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) imaging, and to evaluate the relationship between radiomics features of VAT and positive expression of Her-2 and Ki-67 in gastric cancer (GC). Methods Ninety patients with GC were enrolled in this study. 18F-FDG PET/CT radiomics features were calculated using the PyRadiomics package. Two methods were employed to reduce radiomics features. The machine learning models, logistic regression (LR), and support vector machine (SVM), were constructed and estimated by the receiver operator characteristic (ROC) curve. The correlation of outstanding features with Ki-67 and Her-2 expression status was evaluated. Results For the Ki-67 set, the area under of the receiver operator characteristic curve (AUC) and accuracy were 0.86 and 0.79 for the LR model and 0.83 and 0.69 for the SVM model. For the Her-2 set, the AUC and accuracy were 0.84 and 0.86 for the LR model and 0.65 and 0.85 for the SVM model. The LR model for Ki-67 exhibited outstanding prediction performance. Three wavelet transform features were correlated with Her-2 expression status (p all < 0.001), and one wavelet transform feature was correlated with the expression status of Ki-67 (p = 0.042). Conclusion 18F-FDG PET/CT-based radiomics models of VAT demonstrate good performance in predicting Her-2 and Ki-67 expression status in patients with GC. Radiomics features can be used as imaging biomarkers for GC.

Systemic Therapy of Gastric Cancer—State of the Art and Future Perspectives

Background: The prognosis of patients diagnosed with locally advanced and metastatic gastric and esophago-gastric junction cancer is critical. The optimal choice of systemic therapy is essential to optimize survival outcomes. Methods: A comprehensive literature review via PubMed and analysis of major oncology congresses (European Society for Medical Oncology and American Society of Clinical Oncology websites) were conducted to ascertain the current status and latest developments in the systemic treatment of patients with localized or advanced gastric and esophago-gastric junction adenocarcinoma. Results: While neoadjuvant and perioperative chemotherapy for localized tumor stages is the preferred approach in the Western Hemisphere, adjuvant chemotherapy remains the preferred course of action in East Asia. The administration of chemotherapy, typically in the form of combinations comprising platinum and fluoropyrimidine compounds in combination with docetaxel, represents a standard of care. Investigations are underway into the potential of immunotherapy and other biologically targeted agents in the perioperative setting. To select the most appropriate therapy for advanced gastric cancer, including adenocarcinoma of the esophago-gastric junction, it is essential to determine biomarkers such as HER2 expression, PD-L1 combined positive score (CPS) (combined positive score), Claudin 18.2, and microsatellite instability (MSI). In the present clinical context, the standard first-line therapy is a combination of fluoropyrimidine and a platinum derivative. The selection of chemotherapy in combination with antibodies is contingent upon the specific biomarker under consideration. Conclusions: This article reviews the current state of the art based on recent clinical trial results and provides an outlook on the future of systemic therapy.

HER3 is widely expressed across diverse subtypes of NSCLC in a retrospective analysis of archived tissue samples.

Aim: This noninterventional study (NCT05769764) aimed to characterize human epidermal growth factor receptor 3 (HER3) expression in non-small cell lung cancer (NSCLC) by patient, clinical or tumor characteristics.Methods: HER3 immunohistochemistry was performed in archival tissue samples from patients with advanced or metastatic NSCLC. Samples were scored for membrane percent positivity and intensity. Membrane H-scores were calculated.Results: Of 203 evaluable samples, HER3 expression was observed in 98.5%, including all histologies, genomic subtypes and regardless of prior systemic anticancer treatments. The median H-score was 140, and 70.4% had a HER3 intensity of 3+.Conclusion: HER3 is widely expressed in NSCLC, indicating that HER3-directed therapy may be broadly applicable across diverse subtypes of NSCLC.

Portable Monitoring System for Assessing Therapeutic Efficacy in HER2‐Overexpressing Breast Cancer: One‐Step Simultaneous Detection of Cancer‐Derived Exosomal Proteins and mRNA in Urine

AbstractPoint‐of‐care (POC) monitoring of patient condition is crucial for effective cancer treatment and prognosis. This can be achieved non‐invasively by analyzing exosomes in body fluids. However, the heterogeneity of exosomes and non‐standardized quantification methods may interfere with clearly determining the patient's condition. Therefore, there is a need for technology that can precisely analyze both tumor‐derived exosomes and normal exosomes. Herein, this study presents the exosome multiple‐separation for simultaneous detection (EXO‐MUSSID) platform, which simultaneously isolates different exosomes based on their magnetization properties and monitors therapeutic efficacy of drugs. Using immunoaffinity magnetophoresis technology, HER2‐overexpressing and normal exosomes are collected separately, enabling real‐time monitoring of HER2 (also known as ERBB2) expression by analyzing the mRNA of each exosome based on a catalytic hairpin assembly (CHA) reaction. A portable fluorescence reader customized for the EXO‐MUSSID platform is developed for POC monitoring of HER2‐overexpressing breast cancer (HER2+ BC). The performance of the EXO‐MUSSID platform is validated using urine samples from HER2+ BC mouse models, confirming the progression of HER2+ BC and the changes in HER2 expression due to trastuzumab treatment. It is expected to serve as a valuable tool for exosome‐based liquid biopsy in disease monitoring.

Mechanistic Regulation of Epidermal Growth Factor and Hormonal Receptors by Kinase Inhibitors and Organofluorines in Breast Cancer Therapy.

Differential expression patterns of growth factor (EGFR, HER-2) and hormonal (ER, PR) receptors in breast cancer (BC) remain crucial for evaluating and tailoring therapeutic interventions. This study investigates differential expression profiles of hormonal and growth factor receptors in BC patients and across age groups, major subclasses, disease stages and tumor histology and survival rates, the efficacy of emerging clinical trial drugs (Dabrafenib and Palbociclib) and elucidating their molecular interaction mechanisms for efficient therapeutic strategies. Gene and protein expression analysis in the normal vs BC and across age groups and major subclasses reveals divergent patterns as EGFR and HER-2 levels are reduced in tumors versus normal tissue, while ER and PR levels are higher, particularly in luminal subtypes. However, there was no significant difference in survival rates among high and low/medium expression levels of EGFR and PR receptors. Conversely, patients with high HER-2 and ER expression exhibited poorer survival rates compared to low or medium expression levels. The in vitro findings indicate that Dabrafenib exhibits greater effectiveness than Palbociclib in suppressing various BC cells such as MCF-7 (Luminal), MDA-MB-231 (Triple-Negative), SKBR-3 (HER-2 + ) proliferation, promoting cell death, (IC50 of Dab < Pal) at 24 and 48 h, ROS production, and reduced ER and PR, elevated HER-2 with no change in EGFR expression. Molecular simulation studies revealed Dabrafenib's thermodynamically stable interactions (ΔG), tighter binding, and less structural deviation in the order EGFR > HER-2 > ER > PR as compared to Palbociclib (HER-2 > ER > PR = EGFR). These results indicate that Dabrafenib, compared to Palbociclib, more effectively regulates breast cancer cell proliferation through specific interactions with hormonal and growth factor receptors towards a repurposing approach.

Abstract C039: Nativity and breast cancer outcomes by breast cancer subtype in the ENCLAVE Study

Abstract Background: Associations of nativity and breast cancer (BC) mortality are mixed in studies using cancer registry data. We examined associations in diverse women with detailed individual-level data on BC treatment and subtype. Methods: The study population included 5,718 Asian (n=722, 71% foreign-born), Hispanic (n=631, 42% foreign-born), and non-Hispanic White (n=4,365, 9% foreign-born) women from the ENCLAVE Study diagnosed with invasive BC from 1996-2013 using pooled, harmonized data from two (of three) cohorts with data on BC subtype. Data on nativity, reproductive and behavioral factors were self-reported from questionnaires; data on disease severity, BC subtype (luminal A, luminal B, Her2 expressing, triple negative breast cancer), treatment, and mortality were obtained from cancer registries and electronic health records. Recurrences were identified by recurrence algorithms and medical record review. We fit Cox proportional hazards regression models to examine associations between self-reported nativity and recurrence, BC-specific mortality, and overall mortality. Covariates included age, sociodemographic factors, disease severity, and treatment, reproductive and behavioral factors. We also examined associations by race, ethnicity, and BC subtype. Results: Compared to US-born women, foreign-born women had lower total mortality (hazard ratio [HR]=0.75, 95% confidence interval [CI]: 0.64-0.89); lower risks were suggested for recurrence (HR=0.85, 95% CI: 0.68-1.06) and breast cancer-specific mortality (HR=0.87, 95% CI: 0.66-1.14). Stratified by BC subtype, foreign- (vs. US-) born women had a lower risk of overall mortality among those with luminal A (HR=0.72, 95% CI: 0.56-0.92) and luminal B (HR=0.66, 95% CI: 0.48-0.91) but not other subtypes. Among women with luminal B BC, these associations reached statistical significance for recurrence (HR=0.65, 95% CI: 0.45-0.94) and BC-specific mortality (HR=0.53, 95% CI: 0.33-0.84). We noted no associations in other BC subtypes though analyses of less common subtypes were underpowered. Associations did not differ by race or ethnicity. Conclusion: Foreign-born women with BC had lower risk of overall mortality than US-born women. Risks of recurrence and BC-specific mortality were lower in foreign-born vs. US-born women among those with the luminal B BC subtype. Associations were not explained by behavioral or reproductive factors. Citation Format: Candyce Kroenke, Rhonda Aoki, Stacey Alexeeff, Scarlett Gomez, Bette Caan, Brittany Morey, Jacqueline Torres, Larry Kushi. Nativity and breast cancer outcomes by breast cancer subtype in the ENCLAVE Study [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr C039.

Explainable breast cancer molecular expression prediction using multi-task deep-learning based on 3D whole breast ultrasound

ObjectivesTo noninvasively estimate three breast cancer biomarkers, estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) and enhance performance and interpretability via multi-task deep learning.MethodsThe study included 388 breast cancer patients who received the 3D whole breast ultrasound system (3DWBUS) examinations at Xijing Hospital between October 2020 and September 2021. Two predictive models, a single-task and a multi-task, were developed; the former predicts biomarker expression, while the latter combines tumor segmentation with biomarker prediction to enhance interpretability. Performance evaluation included individual and overall prediction metrics, and Delong’s test was used for performance comparison. The models’ attention regions were visualized using Grad-CAM + + technology.ResultsAll patients were randomly split into a training set (n = 240, 62%), a validation set (n = 60, 15%), and a test set (n = 88, 23%). In the individual evaluation of ER, PR, and HER2 expression prediction, the single-task and multi-task models achieved respective AUCs of 0.809 and 0.735 for ER, 0.688 and 0.767 for PR, and 0.626 and 0.697 for HER2, as observed in the test set. In the overall evaluation, the multi-task model demonstrated superior performance in the test set, achieving a higher macro AUC of 0.733, in contrast to 0.708 for the single-task model. The Grad-CAM + + method revealed that the multi-task model exhibited a stronger focus on diseased tissue areas, improving the interpretability of how the model worked.ConclusionBoth models demonstrated impressive performance, with the multi-task model excelling in accuracy and offering improved interpretability on noninvasive 3DWBUS images using Grad-CAM + + technology.Critical relevance statementThe multi-task deep learning model exhibits effective prediction for breast cancer biomarkers, offering direct biomarker identification and improved clinical interpretability, potentially boosting the efficiency of targeted drug screening.Key PointsTumoral biomarkers are paramount for determining breast cancer treatment.The multi-task model can improve prediction performance, and improve interpretability in clinical practice.The 3D whole breast ultrasound system-based deep learning models excelled in predicting breast cancer biomarkers.Graphical

Concordance of HER2 Expression in Paired Primary and Metastatic Sites of Endometrial Serous Carcinoma and the Effect of Intratumoral Heterogeneity

Primary endometrial serous carcinoma, known for its aggressive nature and poor prognosis, shares similarities with breast and gastric cancers in terms of potential HER2 overexpression as a therapeutic target. Assessing HER expression is complicated by tumor heterogeneity and discrepancies between primary and metastatic sites. In this study, we retrospectively analyzed HER amplification and expression in 16 pairs of primary endometrial serous carcinoma resections and corresponding metastases. HER2 status was determined using immunohistochemistry (IHC), with criteria based on the percentage and intensity of tumor cell staining. Confirmatory techniques, such as dual in situ hybridization (DISH) and fluorescence in situ hybridization (FISH), were also employed. This study reports on the concordance rates and the presence and pattern of HER2 heterogeneity. Our results showed an 87.5% concordance rate in HER2 amplification status between primary and metastatic sites, with 33% of cases scored as 2+ being amplified. Heterogeneity was observed in 100% of amplified cases and 95% of non-amplified cases on in situ testing, with variations in heterogeneity patterns between techniques. In conclusion, our findings emphasize the importance of testing both primary and metastatic sites or recurrences, with a concordance rate of 87.5%. In addition, a review of the literature and combining the results showed a concordance rate of up to 68%. The presence and pattern of heterogeneity, particularly in cases of mosaic or clustered heterogeneity in the primary tumor, may serve as reliable indicators of concordance, predicting a non-amplified HER2 status in corresponding metastases.

Trastuzumab Deruxtecan after Endocrine Therapy in Metastatic Breast Cancer.

Outcomes in patients with hormone receptor-positive metastatic breast cancer worsen after one or more lines of endocrine-based therapy. Trastuzumab deruxtecan has shown efficacy in patients with metastatic breast cancer with low expression of human epidermal growth factor receptor 2 (HER2) after previous chemotherapy. We conducted a phase 3, multicenter, open-label trial involving patients with hormone receptor-positive metastatic breast cancer with low HER2 expression (a score of 1+ or 2+ on immunohistochemical [IHC] analysis and negative results on in situ hybridization) or ultralow HER2 expression (IHC 0 with membrane staining) who had received one or more lines of endocrine-based therapy and no previous chemotherapy for metastatic breast cancer. Patients were randomly assigned in a 1:1 ratio to receive trastuzumab deruxtecan or the physician's choice of chemotherapy. The primary end point was progression-free survival (according to blinded independent central review) among the patients with HER2-low disease. Secondary end points included progression-free survival among all the patients who had undergone randomization, overall survival, and safety. Of the 866 patients who underwent randomization, 713 had HER2-low disease, and 153 had HER2-ultralow disease. Among the patients with HER2-low disease, the median progression-free survival was 13.2 months (95% confidence interval [CI], 11.4 to 15.2) in the trastuzumab deruxtecan group and 8.1 months (95% CI, 7.0 to 9.0) in the chemotherapy group (hazard ratio for disease progression or death, 0.62; 95% CI, 0.51 to 0.74; P<0.001); the results were consistent in the exploratory HER2-ultralow population. Data for overall survival were immature. Adverse events of grade 3 or higher occurred in 52.8% of the patients in the trastuzumab deruxtecan group and in 44.4% of those in the chemotherapy group. Adjudicated interstitial lung disease or pneumonitis occurred in 49 patients (11.3%; three events were grade 5 in severity) and in 1 patient (0.2%; grade 2), respectively. Among patients with hormone receptor-positive, HER2-low or HER2-ultralow metastatic breast cancer who had received one or more lines of endocrine-based therapy, treatment with trastuzumab deruxtecan resulted in longer progression-free survival than chemotherapy. No new safety signals were identified. (Funded by AstraZeneca and Daiichi Sankyo; DESTINY-Breast06 ClinicalTrials.gov number, NCT04494425.).