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HER2, encoded by the ERBB2 gene, is an important druggable driver of human cancer gaining increasing importance as a therapeutic target in urothelial carcinoma (UC). The genomic underpinnings of HER2 overexpression in ERBB2 nonamplified UC are poorly defined. To address this knowledge gap, we investigated 172 UC tumors from patients treated at the University of California San Francisco, using immunohistochemistry and next-generation sequencing. We found that GATA3 and PPARG copy number gains individually predicted HER2 protein expression independently of ERBB2 amplification. To validate these findings, we interrogated the Memorial Sloan Kettering/The Cancer Genome Atlas (MSK/TCGA) dataset and found that GATA3 and PPARG copy number gains individually predicted ERBB2 mRNA expression independently of ERBB2 amplification. Our findings reveal a potential link between the luminal marker HER2 and the key transcription factors GATA3 and PPARG in UC and highlight the utility of examining GATA3 and PPARG copy number states to identify UC tumors that overexpress HER2 in the absence of ERBB2 amplification. In summary, we found that an increase in copy number of GATA3 and PPARG was independently associated with higher ERBB2 expression in patient samples of UC. This finding provides a potential explanation for HER2 overexpression in UC tumors without ERBB2 amplification and a way to identify these tumors for HER2-targeted therapies.

Brain metastatic breast cancer is particularly lethal largely due to therapeutic resistance. Almost half of the patients with metastatic HER2-positive breast cancer develop brain metastases, representing a major clinical challenge. We previously described that cancer-associated fibroblasts are an important source of resistance in primary tumors. Here, we report that breast cancer brain metastasis stromal cell interactions in 3D cocultures induce therapeutic resistance to HER2-targeting agents, particularly to the small molecule inhibitor of HER2/EGFR neratinib. We investigated the underlying mechanisms using a synthetic Notch reporter system enabling the sorting of cancer cells that directly interact with stromal cells. We identified mucins and bulky glycoprotein synthesis as top-up-regulated genes and pathways by comparing the gene expression and chromatin profiles of stroma-contact and no-contact cancer cells before and after neratinib treatment. Glycoprotein gene signatures were also enriched in human brain metastases compared to primary tumors. We confirmed increased glycocalyx surrounding cocultures by immunofluorescence and showed that mucinase treatment increased sensitivity to neratinib by enabling a more efficient inhibition of EGFR/HER2 signaling in cancer cells. Overexpression of truncated MUC1 lacking the intracellular domain as a model of increased glycocalyx-induced resistance to neratinib both in cell culture and in experimental brain metastases in immunodeficient mice. Our results highlight the importance of glycoproteins as a resistance mechanism to HER2-targeting therapies in breast cancer brain metastases.

Objectives: Human epidermal growth factor receptor 2 (HER2)-targeted therapies have demonstrated potential benefits for metastatic colorectal cancer (mCRC) patients with HER2 amplification, but are not satisfactory in cases of HER2 mutant CRCs. Methods: Consequently, further elucidation of amplifications and somatic mutations in erythroblastic oncogene B-2 (ERBB2) is imperative. Comprehensive genomic profiling was conducted on 2454 Chinese CRC cases to evaluate genomic alterations in 733 cancer-related genes, tumor mutational burden, microsatellite instability, and programmed death ligand 1 (PD-L1) expression. Results: Among 2454 CRC patients, 85 cases (3.46%) exhibited ERBB2 amplification, and 55 cases (2.24%) carried ERBB2 mutation. p.R678Q (28%), p.V8421 (24%), and p.S310F/Y (12%) were the most prevalent of the 16 detected mutation sites. In comparison to the ERBB2 altered (alt) group, KRAS/BRAF mutations were more prevalent in ERBB2 wild-type (wt) samples (ERBB2wt vs. ERBB2alt, KRAS: 50.9% vs. 25.6%, p < 0.05; BRAF: 8.5% vs. 2.3%, p < 0.05). 32.7% (18/55) of CRCs with ERBB2 mutation exhibited microsatellite instability high (MSI-H), while no cases with HER2 amplification displayed MSI-H. Mutant genes varied between ERBB2 copy number variation (CNV) and ERBB2 single nucleotide variant (SNV); TP53 alterations tended to co-occur with ERBB2 amplification (92.3%) as opposed to ERBB2 mutation (58.3%). KRAS and PIK3CA alterations were more prevalent in ERBB2 SNV cases (KRAS/PIK3CA: 45.8%/31.2%) compared to ERBB2 amplification cases (KRAS/PIK3CA: 14.1%/7.7%). Conclusion: Our study delineates the landscape of HER2 alterations in a large-scale cohort of CRC patients from China. These findings enhance our understanding of the molecular features of Chinese CRC patients and offer valuable implications for further investigation. [ABSTRACT FROM AUTHOR]

Human epidermal growth factor receptor 2 (HER2) overexpression emerges as an attractive therapeutic target in gynecological malignancies. Recently, Trastuzumab-Deruxtecan (T-DXd) has shown substantial efficacy in HER2 overexpressing carcinomas, most prominently in ovarian, endometrial and cervical patients. We have examined the efficacy of T-DXd in patients with metastatic endometrial, ovarian and cervical malignancies that were treated in the Department of Clinical Therapeutics, Alexandra Hospital, School of Medicine, National and Kapodistrian University of Athens. Methods Patients with gynecological malignancies with HER2 expression 2 + /3 + as assessed by immunohistochemistry (IHC) that were treated with T-DXd were retrospectively identified. Patients received T-DXd intravenously at a dose of 5.4 mg/kg every 3 weeks until disease progression or unacceptable toxicity. Results In total, 10 patients treated with T-DXd for recurrent/metastatic disease were identified. Regarding histology, there were 5 patients with uterine neoplasms (serous carcinoma (n = 3), uterine carcinosarcoma (n = 1), uterine leiomyosarcoma (n = 1)), 1 patient with squamous cervical carcinoma and 4 patients with ovarian cancer (ovarian carcinosarcoma (n = 2), high-grade serous carcinoma (n = 1) and mucinous ovarian carcinoma (n = 1)). Median age was 65.4 years (25th-75th percentile, 58.1–75.2 years). 5 patients had HER2 expression 3 + by IHC and 5 patients had HER2 expression 2 +. Median number of previous lines of therapy was 4 (range 2–6), 2 patients with uterine serous carcinoma were pretreated with trastuzumab and 4 patients had already received immunotherapy. In the entire cohort median progression-free survival (PFS) was 5.4 months (95%CI 0.8–9.8 months). Regarding responses, 5 patients had partial response (including 2 patients that were pretreated with trastuzumab), 1 patient had stable disease at 12 weeks and 4 patients had disease progression at initial assessment. All patients but one that derived clinical benefit had HER2 3 + expression. Discussion In the real-world setting, T-DXd showed activity in a cohort of heavily pre-treated patients with HER2-expressing gynecological malignancies. [ABSTRACT FROM AUTHOR]

Breast cancer that overexpresses Human Epidermal Growth Factor Receptor 2 (HER2+) due to gene amplification or overexpression constitutes 15-20% of all breast cancer cases. Trastuzumab, the first FDA-approved monoclonal antibody targeting HER2, serves as the standard first-line treatment for HER2-positive advanced breast cancer, as recommended by multiple clinical guidelines.Currently, accumulated clinical evidence reveals a considerable degree of variability in the response of HER2+ breast cancer to trastuzumab treatment. Specifically, over 50% of patients either do not respond to or develop resistance against trastuzumab.The specific mechanisms of resistance to trastuzumab are currently unclear. This paper aims to review the existing research on the resistance mechanisms of trastuzumab, based on its target, from aspects such as genetic loci, molecular structure, signaling pathways, and the tumor microenvironment and to outline current research progress and new strategies. [ABSTRACT FROM AUTHOR]

Aims: Recently, human epidermal growth factor 2 (HER2)‐low (i.e. HER2 score 1+ or 2+ without amplification) breast cancer patients became eligible for trastuzumab–deruxtecan treatment. To improve assay standardisation and detection of HER2‐low in a quantitative manner, we conducted an external quality assessment‐like study in the Netherlands. Dynamic range cell lines and immunohistochemistry (IHC) calibrators were used to quantify HER2 expression and to assess interlaboratory variability. Methods and results: Three blank slides with a dynamic range cell line and an IHC calibrator were stained with routine HER2 assays by 35 laboratories. Four different antibody clones were used: 19 (54.3%) 4B5, six (17.1%) A0485, five (14.3%) DG44 (HercepTest) and five (14.3%) SP3. Laboratories used two different detection kits for 4B5 assays: 14 (73.7%) ultraView and five (26.3%) OptiView. Variability of HER2 expression in cell lines, measured with artificial intelligence software, was median (min–max) = negative core 0.5% (0.0–57.0), 1+ core 4.3% (1.6–71.3), 2+ core 42.8% (30.4–92.6) and 3+ core 96.2% (91.8–98.8). The calibrators DG44 and 4B5 OptiView had the highest analytical sensitivity, closely followed by 4B5 ultraView. SP3 was the least sensitive. Calibrators of A0485 assays were not analysable due to background staining. Conclusions: As assays were validated for detecting HER2‐amplified tumours, not all assays and antibodies proved suitable for HER2‐low detection. Some tests showed distinct expression in the negative cell line. Dynamic range cell line controls and quantitative analysis using calibrators demonstrated more interlaboratory variability than commonly appreciated. Revalidation of HER2 tests by laboratories is needed to ensure clinical applicable HER2‐low assays. [ABSTRACT FROM AUTHOR]

As the first anti-HER2 targeted agent approved by FDA in 1998, Trastuzumab has significantly improved the outcome of patients with HER2 positive metastatic breast cancer. Unfortunately, resistance to trastuzumab is a severe obstacle to its therapeutic efficacy in clinical application, and its mechanism has not yet been fully elucidated. In our study, we found that stabilization of cyclin D3 could be one reason for trastuzumab resistance. Trastuzumab could induce G1/G0 phase arrest by downregulating cyclin D3 protein expression. However, the protein expression of cyclin D3 was not affected in trastuzumab-resistant cells, which might be related to aberrant activation of ERK signaling pathway. Furthermore, degradation of cyclin D3 protein by trastuzumab was mainly resulted from ubiquitin-dependent proteasome mechanism instead of transcriptional regulation. In trastuzumab-resistant breast cancer cells, trastuzumab-induced degradation of cyclin D3 protein was abrogated. When the ubiquitin pathway was inhibited, cells would show a predisposition to resistance to trastuzumab. Further, CDK4/6 inhibitor can inhibit the proliferation of trastuzumab-resistant HER-2 positive breast cancer cells. Therefore, combination of CDK4/6 inhibitors and anti-HER2 targeted therapy may be an alternative and promising strategy to overcome trastuzumab resistance in the future. [ABSTRACT FROM AUTHOR]

Background: The human epidermal growth factor receptor 2 (HER2) has recently emerged as hotspot in targeted therapy for urothelial bladder cancer (UBC). The HER2 status is mainly identified by immunohistochemistry (IHC), preoperative and noninvasive methods for determining HER2 status in UBC remain in searching. Purposes: To investigate whether radiomics features extracted from MRI using machine learning algorithms can noninvasively evaluate the HER2 status in UBC. Study Type: Retrospective. Population: One hundred ninety‐five patients (age: 68.7 ± 10.5 years) with 14.3% females from January 2019 to May 2023 were divided into training (N = 156) and validation (N = 39) cohorts, and 43 patients (age: 67.1 ± 13.1 years) with 13.9% females from June 2023 to January 2024 constituted the test cohort (N = 43). Field Strength/Sequence: 3 T, T2‐weighted imaging (turbo spin‐echo), diffusion‐weighted imaging (breathing‐free spin echo). Assessment: The HER2 status were assessed by IHC. Radiomics features were extracted from MRI images. Pearson correlation coefficient and the least absolute shrinkage and selection operator (LASSO) were applied for feature selection, and six machine learning models were established with optimal features to identify the HER2 status in UBC. Statistical Tests: Mann–Whitney U‐test, chi‐square test, LASSO algorithm, receiver operating characteristic analysis, and DeLong test. Results: Three thousand forty‐five radiomics features were extracted from each lesion, and 22 features were retained for analysis. The Support Vector Machine model demonstrated the best performance, with an AUC of 0.929 (95% CI: 0.888–0.970) and accuracy of 0.859 in the training cohort, AUC of 0.886 (95% CI: 0.780–0.993) and accuracy of 0.846 in the validation cohort, and AUC of 0.712 (95% CI: 0.535–0.889) and accuracy of 0.744 in the test cohort. Data Conclusion: MRI‐based radiomics features combining machine learning algorithm provide a promising approach to assess HER2 status in UBC noninvasively and preoperatively. Evidence Level: 2 Technical Efficacy: Stage 3 [ABSTRACT FROM AUTHOR]

Background: Breast cancer remains the most common invasive cancer in women worldwide. Triple-negative breast cancer (TNBC) is an aggressive subtype with limited treatment options. Trastuzumab (Tz) is typically used to treat HER2-positive breast cancers, but its potential in TNBC is unclear. Objectives: To investigate the effects of trastuzumab on cell viability, apoptosis, cell cycle progression, and gene expression in TNBC cell lines compared with HER2-positive and normal cell lines. Design: This is an in vitro experimental pre-clinical study using cultured cancer cell lines. Methods: MDA-MB-231 and 4T1 (TNBC), MCF-7 (HER2 -positive), and HSF (normal) cell lines were treated with 20 μg/mL trastuzumab for 24 hours. Cell viability was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, apoptosis by flow cytometry, cell cycle progression by DNA content analysis, and gene expression by qPCR. Results: Trastuzumab significantly reduced cell viability and induced apoptosis in TNBC cell lines, comparable to effects in HER2-positive MCF-7 cells. Cell cycle analysis revealed G2/M phase arrest in TNBC cells. Gene expression analysis showed upregulation of ERBB2, NOTCH1, EGFR, PIK3CA, and PTEN in MDA-MB-231 cells, while 4T1 cells exhibited downregulation of most genes except NOTCH1. Conclusion: This study provides initial evidence for trastuzumab's potential therapeutic effects in TNBC, despite low HER2 expression. The observed cytotoxicity, apoptosis induction, and cell cycle modulation in TNBC cells warrant further investigation into trastuzumab's mechanisms of action in HER2 -negative contexts and its potential repurposing for TNBC treatment. [ABSTRACT FROM AUTHOR]

Background: Human epidermal growth factor receptor 2-targeted (HER2) therapy with antibody-drug conjugates has proven effective for patients with HER2-low breast cancer. However, intratumoral heterogeneity (ITH) poses a great challenge in identifying HER2-low tumors. ITH signatures were developed by quantifying ITH to differentiate HER2-positive, -low and -zero breast cancers. Methods: This retrospective study included 614 patients from two institutions. The study was structured into two primary tasks: task 1 was to differentiate between HER2-positive and -negative tumors, followed by task 2 to differentiate HER2-low and -zero tumors. Whole-tumor radiomics features and habitat radiomics features were extracted from MRI to construct the radiomics and ITH signatures. Multivariable logistic regression analysis was used to determine significant independent predictors. A combined model integrating significant clinicopathologic variables, radiomics signature, and ITH signature was developed for task (1) Subsequently, the better-performing model was established using the same approach for task (2) The area under the receiver operating characteristic curve (AUC) was used to assess the performance of each model. Results: Task 1 comprised 614 patients (training, n = 348; validation, n = 149; and test cohorts, n = 117). Task 2 encompassed 501 patients (training, n = 283; validation, n = 122; and test cohorts, n = 96). For task1, the ITH signature showed outstanding performance, achieving AUCs of 0.81, 0.81, and 0.81 in the training, validation and test cohorts, respectively. The combined model achieved improved performance, with AUCs of 0.83, 0.84 and 0.83 across the three cohorts, respectively. For task2, the ITH signature maintained superior performance, with AUCs of 0.94, 0.93 and 0.84 across the training, validation and test cohorts, respectively. Multivariable logistic regression analysis indicated that none of the clinicopathologic characteristics were retained as predictors associated with odds of HER2-low tumors. Conclusions: Our study developed ITH signatures that quantified ITH using habitat-based MRI radiomics, achieving outstanding performance in differentiating HER2-postive and -negative tumors, and further differentiating HER2-low and -zero breast cancers. [ABSTRACT FROM AUTHOR]

Targeted cancer therapy is a promising alternative to the currently established cancer treatments, aiming to selectively kill cancer cells while sparing healthy tissues. Hereby, molecular targeting agents, such as monoclonal antibodies, are used to bind to cancer cell surface markers specifically. Although these agents have shown great clinical success, limitations still remain such as low tumor penetration and off-target effects. To overcome this limitation, novel fusion proteins comprised of the two proteins ADAPT6 and Horseradish Peroxidase (HRP) were engineered. Cancer cell targeting is hereby enabled by the small scaffold protein ADAPT6, engineered to specifically bind to human epidermal growth factor receptor 2 (HER2), a cell surface marker overexpressed in various cancer types, while the enzyme HRP oxidizes the nontoxic prodrug indole-3-acetic acid (IAA) which leads to the formation of free radicals and thereby to cytotoxic effects on cancer cells. The high affinity to HER2, as well as the enzymatic activity of HRP, were still present for the ADAPT6-HRP fusion proteins. Further, in vitro cytotoxicity assay using HER2-positive SKOV-3 cells revealed a clear advantage of the fusion proteins over free HRP by association of the fusion proteins directly to the cancer cells and therefore sustained cell killing. This novel strategy of combining ADAPT6 and HRP represents a promising approach and a viable alternative to antibody conjugation for targeted cancer therapy. [Display omitted] • A novel fusion protein for targeted cancer therapeutics is presented. • The fusion protein combines high affinity to HER2 with enzymatic activity. • The therapeutic protein is easily produced in the bacterial host E. coli. • Efficient cancer cell killing through tumor cell-specific binding and activity has been demonstrated. [ABSTRACT FROM AUTHOR]

Simple Summary: Brain metastases from gastric cancer are rare but pose serious challenges for patients and doctors due to their impact on survival and quality of life. Despite improvements in cancer treatment, brain metastases remain difficult to treat, and there is little clear guidance on the best approaches. This study aims to gather and analyze the available research to better understand how common brain metastases are in gastric cancer patients, what factors may increase the risk, and how different treatments, including surgery, affect patient survival. By providing clearer information, this research hopes to guide doctors in choosing the most effective treatments and highlight areas where further study is needed. Background: Brain metastases (BM) from gastric cancer (GC) are rare but associated with poor prognosis, significantly impacting patient survival and quality of life. The objective of this systematic review and meta-analysis is to consolidate existing research on BM from GC, evaluate the incidence and clinical outcomes, and explore the effectiveness of treatment options. Methods: A systematic search was conducted across the Medline, Web of Science, and Scopus databases, following PRISMA guidelines. Eighteen high-quality studies, as per the Newcastle–Ottawa Quality Assessment Scale, were included, encompassing 70,237 GC patients, of whom 621 developed BM. Data on progression-free survival (PFS), overall survival (OS), neurological symptoms, and HER2 status were analyzed using a random-effects model. Results: The incidence of BM in GC patients was found to be 2.29% (95% CI: 1.06–3.53%), with the range extending from 0.47% to 7.79% across studies. HER2-positive status was significantly associated with a higher likelihood of developing BM, with an odds ratio of 43.24 (95% CI: 2.05–913.39; p = 0.02), although this finding was based on limited data. The surgical resection of BM was linked to significantly improved survival outcomes, with a mean difference in OS of 12.39 months (95% CI: 2.03–22.75; p = 0.02) compared to non-surgical approaches. Conclusions: The surgical resection of brain metastases in GC patients significantly enhances overall survival, while HER2-positive patients may show a higher risk for developing BM. These findings underscore the importance of tailored therapeutic approaches for GC patients with BM. [ABSTRACT FROM AUTHOR]

Breast cancer is one of the most common malignancies affecting women worldwide, with a significant need for novel therapeutic agents to target specific molecular pathways involved in tumor progression. In this study, a series of rhodanine–piperazine hybrids were designed, synthesized, and evaluated for their anticancer activity, targeting key tyrosine kinases such as VEGFR, EGFR, and HER2. Biological screening against breast cancer cell lines (MCF-7, MDA-MB-231, T47D, and MDA-MB-468) revealed 3 of the 13 tested compounds as the most potent, with 5-({4-[bis(4-fluorophenyl)methyl]piperazin-1-yl}methylidene)-2-thioxo-1,3-thiazolidin-4-one (12) showing the strongest activity, particularly against the MCF-7 and MDA-MB-468 cell lines. Molecular docking studies indicated favorable binding interactions of compound 12 and its 3-phenyl-2-thioxo-1,3-thiazolidin-4-one analogue (15) with HER2, VEGFR, and EGFR, and molecular dynamics simulations further confirmed their stable binding to HER2. These findings highlight the potential of rhodanine–piperazine hybrids as promising leads for developing new anticancer agents targeting breast cancer, particularly HER2-positive subtypes. Further structural optimization could enhance their efficacy and therapeutic profile. [ABSTRACT FROM AUTHOR]

Targeted treatment of advanced or metastatic urothelial carcinomas (UCs) requires the identification of druggable mutations. This study describes the development of a 3′ Rapid Amplification of cDNA Ends (3′ RACE)-based targeted RNA sequencing panel which accounts for the status of all genes relevant to UC treatment, namely, FGFR1-4, KRAS, NRAS, BRAF, ERBB2 (HER2), CD274 (PD-L1) and PIK3CA. FGFR2/3-activating point mutations or fusions were found in 54/233 (23.2%) tumors. FGFR3 rearrangements were identified in 11 patients, with eight of them being undetectable by commonly used PCR kits. In addition, one tumor contained a high-copy FGFR2 gene amplification accompanied by strong overexpression of the gene. Mutations in RAS/RAF genes were present in 30/233 (12.9%) UCs and were mutually exclusive with alterations affecting FGFR2/3 genes. On the contrary, activating events in the HER2 oncogene (point mutations and overexpression), as well as PIK3CA mutations, which were relatively common, occurred with similar frequencies in RAS/RAF- or FGFR2/3-positive vs. negative samples. High PD-L1 mRNA expression was associated with advanced disease stage and was not observed in tumors with increased HER2 mRNA expression or in UCs with evidence for FGFR2/3 activation. Three of the studied carcinomas had high-level microsatellite instability (MSI). Overall, more than half of the UCs had potentially druggable genetic alterations. The proposed NGS panel permits comprehensive and cost-efficient analysis of UC-specific molecular targets and may be considered in clinical routine. [ABSTRACT FROM AUTHOR]

Background: Colorectal cancer (CRC) is a leading cause of cancer-related mortality, highlighting the necessity for multifaceted treatment strategies, including preoperative treatment (PT), which can enhance surgical outcomes and provide prognostic insights. This study aims to clarify the impact of PT-induced changes in mismatch repair (MMR) and human epidermal growth factor receptor 2 (HER2) expression, potentially informing tailored treatment strategies and improving clinical outcomes for CRC patients. Methods: This retrospective study analyzed 120 paired samples from CRC patients who underwent preoperative treatment, comparing pre- and post-treatment specimens. A control group of 60 untreated surgical specimens was also included. Immunohistochemistry assessed MMR proteins (MSH6, MSH2, MLH1, PMS2) and HER2 expression. MSI status was determined in samples with low MMR expression. Results: Compared to pre-treatment samples, post-treatment samples exhibited lower levels of MSH6, MSH2, and total MMR expression, along with higher levels of HER2 expression. However, when compared to the untreated control group, there were no significant differences in the expression of MSH6, total MMR, and HER2. All samples that exhibited weak MMR expression and those that shifted to deficient mismatch repair (dMMR) status following treatment had stable microsatellite status. No clear clinicopathological characteristics or prognostic factors were found to be associated with changes in MMR and HER2 expression, except for the use of fluorouracil or capecitabine, which was related to changes in total MMR scores. ypTNM stage and TRG scores were identified as independent factors affecting disease progression in our study. Conclusions: PT is associated with a reduction in MMR expression, notably for the MSH2 protein, while it does not appear to influence HER2 expression. [ABSTRACT FROM AUTHOR]

Purpose: Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) have improved patient survival in hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2−) metastatic breast cancer (mBC) in clinical trials and real-world studies. However, investigations of survival gains in broader HR+/HER2− mBC populations using epidemiological approaches are limited. Methods: This retrospective study used SEER registry data to assess breast cancer-specific survival (BCSS) in patients diagnosed with HR+/HER2− de novo mBC from 2010 to 2019. Kaplan–Meier and Cox proportional hazards models were used to compare BCSS in patients diagnosed before (2010‒2013 with follow-up to 2014) and after (2015‒2018 with follow-up to 2019) the 2015 guideline recommendations for CDK4/6i use. A comparison was made to patients with HR+/HER2-positive (HER2+) de novo mBC, for which no major guideline changes occurred during 2015–2018. Results: Data from 11,467 women with HR+/HER2− mBC and 3260 women with HR+/HER2+ mBC were included. After baseline characteristic adjustment, patients with HR+/HER2− mBC diagnosed post-2015 (n = 6163), had an approximately 10% reduction in risk of BC-specific death compared with patients diagnosed pre-2015 (n = 5304; HR = 0.895, p < 0.0001). Conversely, no significant change was observed in HR+/HER2+ BCSS post-2015 (n = 1798) versus pre-2015 (n = 1462). Similar results were found in patients aged ≥ 65 years. Conclusion: Using one of the largest US population-based longitudinal cancer databases, significant improvements in BCSS were noted in patients with HR+/HER2− mBC post-2015 versus pre-2015, potentially due to the introduction of CDK4/6i post-2015. No significant improvement in BCSS was observed in patients with HR+/HER2+ mBC post-2015 versus pre-2015, likely due to the availability of HER2-directed therapies in both time periods. [ABSTRACT FROM AUTHOR]

Background: This is the first case report describing a patient with non-small cell lung cancer (NSCLC) harboring two rare human epidermal growth factor receptor 2 (HER2) exon 21 insertion mutations, who responded to furmonertinib treatment. Furmonertinib maybe one effective and economical treatment for NSCLC patients harboring HER2 mutations with minor side effects. Case description: We present a case report of a 49-year-old female diagnosed with stage IV lung adenocarcinoma who complained of irritating dry cough symptoms followed by chest tightness. Firstly, we describe the patient's treatment history, including failed third-line combination treatments of systemic chemotherapy with bevacizumab or carrelizumab or anlotinib, primary lung tumor recurrence, bilateral lung metastases progression, and new brain metastatic lesion detection. Next, we detail the patient's fourth-line treatment with radiotherapy for brain metastases and two cycles of bevacizumab plus Abraxane and cisplatin, however, the disease progressed and relapsed. After that, comprehensive genomic profiling revealed two HER2 exon 21 insertion mutations. Subsequently, the patient received targeted therapy with furmonertinib and achieved 11 months of progression-free survival. The patient received pyrrotinib therapy for 2 months after disease progression, but the disease continued to progress. In October 2023, the patient received therapy with furmonertinib again, and a month later, the disease went into partial remission. However, the patient died due to hypoproteinemia combined with severe pneumonia in December 2023. Conclusion: Furmonertinib may be effective for NSCLC patients with HER2 T8962A and L869R mutations and further studies are needed to confirm these results in prospective clinical trials. [ABSTRACT FROM AUTHOR]

Gastric cancer (GC) is a malignancy with poor prognosis and high heterogeneity. For HER2-positive, PD-L1 negative metastatic GC patients, chemotherapy plus trastuzumab is the first-line therapy. However, such patients soon acquired resistance to treatment, especially to trastuzumab during the treatment. Improving the therapeutic resistance of HER2-positive, PD-L1 negative metastatic GC is still a dilemma. We present the case of a metastatic GC patient with HER2-positive and PD-L1-negative expression who suffered progression after a short remission with trastuzumab plus chemotherapy. The patient exhibited strong heterogeneity in the primary and metastatic lesions. His resistance to trastuzumab was overcome after the addition of a PD-1 inhibitor, after which he received a durable response for more than 8 months. In HER2-positive, PD-L1-negative metastatic GC, the addition of PD-1 inhibitors after first-line chemotherapy and trastuzumab treatment resistance may be an option. [ABSTRACT FROM AUTHOR]

Simple Summary: Breast cancer is the most common malignancy in women globally. Genome-wide association studies on breast cancer have found a strong association with fibroblast growth factor receptor 2 (FGFR2). Using publicly available data, we found a higher gene expression of FGFR2 in the less aggressive luminal cancers, and a lower gene expression in HER2-positive breast cancers. The FGFR2 IIIb splice isoform was more common in oestrogen-receptor-positive cancer, while the FGFR2 IIIc splice isoform was more common in HER2-positive carcinomas. Fibroblast growth factor receptor 2 (FGFR2) has been associated with breast cancer. We performed in silico analyses to investigate the FGFR2 mRNA expression and splice variants associated with breast cancer subtypes. Online databases, including cBioPortal and TCGA SpliceSeq, were used to examine the association between the FGFR2 expression and splice variants with breast cancer subtypes. A higher FGFR2 mRNA was significantly associated with luminal, oestrogen receptor (ER)-positive breast cancers, and invasive lobular carcinomas, whereas a lower FGFR2 was associated with human epidermal growth factor receptor 2 (HER2)-positive breast cancer and invasive ductal carcinomas. The epithelial alternatively spliced FGFR2 IIIb isoform was significantly enriched in ER+ breast cancer, while the mesenchymal FGFR2 IIIc isoform was significantly prevalent in HER2+ cancer. Increased levels of FGFR2 and IIIb splice isoforms are associated with less aggressive breast cancer phenotypes, while decreased levels of FGFR2 and increased IIIc splice isoform are associated with more aggressive phenotypes. [ABSTRACT FROM AUTHOR]

Non-immunoglobulin-based scaffold proteins (SPs) represent one of the key therapeutic target-specific and high-affinity binders in modern medicine. Among their cellular targets are signaling receptors, in particular, receptor tyrosine kinases, whose dysfunction leads to the development of cancer and other serious diseases. Successful applications of SPs have been reported for HER receptor type 2 (HER2), a member of the human epidermal growth factor receptor family that regulates cell growth and differentiation. To extend the blood residence of SPs and prevent their high accumulation in the kidneys, these proteins are often fused with serum albumin. Promising results for HER2-binding activity were obtained for SP G3 from the DARPins (Designed Ankyrin Repeat Proteins) family fused with an albumin-binding domain (ABD). Interestingly, the detected HER2–G3 binding strongly depended on the position of the G3 module in the sequence of the constructs. Further improvement of these constructs for biomedical applications requires deciphering the molecular mechanism responsible for this effect. Here, we investigate the structural and dynamic aspects of ABD–G3 and G3–ABD chimeras using NMR spectroscopy and molecular modeling. Based on biophysical data, we come to the conclusion that extensive inter-domain contacts form in both constructs, although their binding interfaces and complex stability are somewhat different. Also, it is shown that the domain linker plays an important role—it limits the accessibility of the detected protein–protein binding sites, depending on the order of the domains in the chimeric molecules. These results create a solid structural basis for the rational design of new effective SP constructs targeting the signaling receptors in cells. [ABSTRACT FROM AUTHOR]

TRPM7 is a divalent cation-permeable channel that is highly active in cancer cells. The pharmacological inhibitors of TRPM7 have been shown to suppress the proliferation of tumor cells, highlighting TRPM7 as a new anticancer drug target. However, the potential benefit of combining TRPM7 inhibitors with conventional anticancer therapies remains unexplored. Here, we used genome-wide transcriptome profiling of human leukemia HAP1 cells to examine cellular responses caused by the application of NS8593, the potent inhibitor of the TRPM7 channel, in comparison with two independent knockout mutations in the TRPM7 gene introduced by the CRISPR/Cas9 approach. This analysis revealed that TRPM7 regulates the expression levels of several transcripts, including HER2 (ERBB2). Consequently, we examined the TRPM7/HER2 axis in several non-hematopoietic cells to show that TRPM7 affects the expression of HER2 protein in a Zn2+-dependent fashion. Moreover, we found that co-administration of pharmacological inhibitors of HER2 and TRPM7 elicited a synergistic antiproliferative effect on HER2-overexpressing SKBR3 cells but not on HER2-deficient MDA-MB-231 breast cancer cells. Hence, our study proposes a new combinatorial strategy for treating HER2-positive breast cancer cells. [ABSTRACT FROM AUTHOR]

Explore whether the axillary outcomes differ among HER2 positive subgroups receiving standard dual-targeted therapy, aiming to identify subgroups exhibiting enhanced sensitivity to NAT among HER2-positive/node-positive breast cancer patients. HER2 positive female patients with biopsy-proven node-positive disease from April 2020 to May 2023 were included. All patients underwent standard Neoadjuvant HER2-targeted dual therapy and axillary lymph node dissection (ALND) at Breast Surgery Center of Sichuan Cancer Hospital. Univariate and multivariate analyses were used to identify factors associate with axillary pathological complete response (ApCR). Statistical analysis and graphing were performed using SPSS 24.0 and GraphPad Prism 9.0 software. This study enrolled 215 HER2 positive patients with a total ApCR rate of 76.7%, which included 49 HER2 2+/FISH + and 166 HER2 3 + cases with approximate ApCR rates of 63.3% and 80.7% (P = 0.011). Univariate and multivariate analysis indicated that HER2 3 + disease (OR = 2.43, 95% CI 1.21–4.88, P = 0.012), Ki-67 ≥ 20% disease (OR = 3.00, 95% CI 1.26–7.13, P = 0.013) and NAC regimen of TCb (OR = 2.71, 95% CI 1.39–5.38, P = 0.004) were more likely to achieve ApCR. Further subgroup analysis revealed that HER2 3 + patients receiving TCb regimen showed the highest ApCR rate of 88% compared to other subgroups. HER2 3 + breast cancer had a higher ApCR rate than HER2 2+/FISH + breast cancer during Neoadjuvant HER2-targeted dual therapy. HER2 positive patients could benefit from NAC regimen of TCb in axillary response. [ABSTRACT FROM AUTHOR]

Oesophago-gastric cancers (OGCs) are amongst the most commonly diagnosed malignancies worldwide and are associated with high disease-related mortality. Predictive biomarkers are molecules that can be objectively measured and used to indicate a likely response to therapeutic intervention, thus facilitating individualised cancer therapy. However, there remains variation in uptake and implementation of biomarker testing across the UK. We conducted a modified Delphi study to formulate consensus recommendations for best-practice biomarker testing of OGC in the UK. We employed two rounds of online questionnaires followed by a virtual consensus meeting. Biomarkers for discussion included HER2, MSI/MMR, and PD-L1. Topics comprised the overall biomarker pathway, pre-analytical, analytical, and post-analytical considerations, including challenges in current practice. Twenty-six and eighteen participants completed the first and second round Delphi questionnaire, respectively, with an even split of pathologists and oncologists from across the UK. There was consensus (>80% agreement) across several topics, including the requirements for standardisation of the pathway, which must include coordination throughout the tissue journey, requirements for a quality-assured process to ensure accuracy and validity of testing, plus the need for clear, detailed information on the pathology report to support treatment decisions. There was consensus amongst oncologists regarding reflex testing of all biomarkers depending on histology; however, concerns over capacity in relation to workload and availability of pathologists were evident among the pathologists. Overall, participants were in the opinion that reflex testing improves the speed of treatment decisions and improves patient care. The recommendations reflect best-practices and should be implemented to support rapid multidisciplinary team decision-making within oesophago-gastric cancer. Results reflect the need for standardisation and demonstrate the challenges faced in clinical practice by those requesting and testing biomarkers for oesophago-gastric cancer, suggesting significant concerns relating to pathologist capacity. • Recommendations for a biomarker pathway for oesophago-gastric cancer were formulated. • Coordination from biopsy request to communication of results are required. • Sufficient capacity and funding should be in place to accommodate reflex testing. [ABSTRACT FROM AUTHOR]

Biological behaviour of Periampullary cancers (PACS) differs from pancreatic head cancer, and analysis of molecular alteration is needed. BRAF and HER2 are keys members of the RAS/RAF and EGFR pathway, playing roles in prognostic markers and therapeutic targets. A study on 89 PACS patients, undergoing Whipple Pancreaticoduodenectomy, PCR-RFLP, and qPCR methods used for SNP and mRNA expression studies. Clinicopathological and survival data collected. Molecular changes were correlated with Clinicopathological parameters. Survival outcomes were assessed by Kaplan Meir Log rank test. The study revealed that homozygous mutant BRAF V600E was significantly higher in PAC compared to a healthy control (p = 0.0012). Whereas the genotype frequency of HER2 I1655V was similar among PAC and healthy control. The A > G change in HER2 was associated with tumor arising from duodenum (p = 0.004) and showed poor survival outcome (p = 0.001). Upregulation of BRAF and HER2 was found in 43 % of patients with synergistic effect, the median overall survival (OS) being 50.5 ± 13 months. The increased expression of HER2 was higher in early stage (p = 0.04) PAC. The gene expression did not impact the OS, whereas female gender, G3 tumors, T3-T4 depth of tumour, advanced stage, LN metastasis, LVI and PNI were poor predictors of OS. BRAF V600E SNP was associated with disease susceptibility, and had increased mRNA expression while HER2 I1655V SNP was associated with poor survival outcome in PAC. The increased expression of BRAF and HER2 in early tumors and their co-expression in PAC exhibit cross talk between RAS/RAF and EGFR pathway in PAC. [ABSTRACT FROM AUTHOR]

Background/Aim: Exosomes are extracellular vesicles produced by both normal and cancer cells. Previous research has demonstrated that circulating exosomes derived from cancer cells may create a niche for future metastasis, distant from the primary tumor. In the present report, circulating exosomes were captured and quantified based on exosomesurface proteins in pre- and post-operative serum of breast cancer patients, focusing on the exosome markers CD9 and CD63, as well as HER2, a therapeutic target for breast cancer. Materials and Methods: Eight breast cancer patients were recruited, and their pre- and post-operative serum samples were analyzed for CD63 and CD9; or CD9 and human epidermal growth factor receptor-2 (HER2), double-positive exosomes. An ExoCounter with antibody-conjugated beads was used to capture serum-derived exosomes. Sera from patients with tumors larger than 10 mm were used for analysis. The resected breast cancer was also histopathologically analyzed for the presence of HER2. Results: CD63 and CD9 double-positive serum exosomes and CD9 and HER2 double-positive serum exosomes decreased after surgery in breast-cancer patients whose tumors expressed HER2, as determined by histopathological analysis. Conclusion: Serum exosomes expressing CD9, CD63 and HER2 are candidate biomarkers of tumor burden in HER2-positive breast-cancer patients. [ABSTRACT FROM AUTHOR]

Breast cancer (BC) is a leading global concern for women, with 30% being HER2-positive cases linked to poorer outcomes. Targeted therapies like trastuzumab deruxtecan (T-DXd), trastuzumab, pertuzumab, and T-DM1 have revolutionized HER2-positive metastatic breast cancer (MBC) treatment. Although these therapies have improved MBC management and patient outcomes, resistance can develop, reducing effectiveness. Personalized strategies based on tumor characteristics offer hope for better responses and longer outcomes. This review outlines insights into MBC patients responding well to anti-HER2 treatments, even across multiple treatment regimen. Recent immunotherapy, locoregional therapy, and liquid biopsy breakthroughs are covered, suggesting ways to increase long-term responders. Personalized approaches have boosted HER2-positive MBC outcomes, and ongoing research is crucial to uncover new treatments and biomarkers, potentially elevating long-term response rates and prognoses. This may aid in providing new direction to breast cancer clinics. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to find whether the proliferation and migration of triple negative breast cancer (TNBC) cell lines can be reduced by treatment with bromodomain and extra-terminal domain (BET) inhibitor JQ1 and BET protein targeting chimeras (PROTACs) ARV-771 and MZ1. Methods: Cytotoxicity tests, scratch migration assays and western blot proteome profiler arrays for protein expression of cancer-related proteins were used to evaluate the impact of a BET-inhibitor and two BET-directed PROTACs on cell viability, migration and on protein expression. Results: JQ1 and the PROTACs MZ1 and ARV-771 significantly inhibited the growth and migration of the KRAS G13D-mutated MDA-MB-231 cells. In this cell line, the PROTACs suppressed the residual expression of ERBB2/HER2, 3 and 4 that are essential for the proliferation of breast cancer cells and this cell line proved sensitive to HER2 inhibitors. In contrast, the effects of the PROTACs on the protein expression of MDA-MB-436 cells mostly affected cytokines and their cognate receptors. Conclusion: The degradation of BET-protein by PROTACs demonstrated significant anti-proliferative effects. The KRAS-mutated MDA-MB-231 cells belong to the low-HER2 expressing tumors that have a poorer prognosis compared to HER2-null patients. Since first oral PROTACs against tumor hormone receptors are in clinical trials, this mode of tumor therapy is expected to become an important therapeutic strategy in the future treatment of TNBC. [ABSTRACT FROM AUTHOR]

Objective: This study analyzes the development, benefits, trial evidence, and price of new breast cancer drugs with US Food and Drug Administration (FDA) approval. Methods: We identified 26 drugs with 42 FDA-approved indications for early and metastatic breast cancer (2000–2023). Data were collected from FDA labels, clinicaltrials.gov, and Medicare and Medicaid. Overall survival (OS) and progression-free survival (PFS) hazard ratios (HRs) and tumor response's relative risk (RR) alongside objective response rate (ORR) were meta-analyzed. Results: The median development time for breast cancer drugs was 7.8 years (95% CI 6.2–10.8). 26% of treatments were considered innovative ("first-in-indication") with 88% acting via a targeted mechanism. 64% were small molecules, 19% antibodies, and 18% antibody-drug conjugates. 38% were approved for HR + and 31% for HER2 + breast cancer. 6 indications were for early and 36 for metastatic breast cancer. Indications utilized FDA's special programs: orphan (2%), fast track (24%), accelerated approval (19%), priority review (74%), breakthrough therapy (44%). Approval was predominantly supported by phase 3 trials (88%) of randomized controlled design (66%), enrolling a median of 585 patients (IQR 417–752) at 181 centers (IQR 142–223) across 19 countries (IQR 17–20). New drugs' HR were 0.78 for OS (95% CI 0.74–0.82) and 0.59 for PFS (95% CI 0.54–0.64) with a RR for tumor response of 1.61 (95% CI 1.46–1.76). Median improvements of OS were 2.8 months (IQR 1.8–5.8) and PFS were 4.4 months (IQR 2.2–7.1). In single-arm trials, the average ORR was 31% (95% CI 10–53). In meta-regressions, the correlation between OS/PFS was 0.34 (p = 0.031) and OS/response was 0.01 (p = 0.435). 60% of treatments had a 'high-value' ESMO-MCBS score with 14% demonstrating improvements in quality of life. The median price was $16,013 per month (95% CI 13,097–17,617). There was no association between prices and patient benefit. The median value per life year gained was $62,419 (IQR 25,840–86,062). Conclusions: Over the past two decades, the development of innovative and effective drugs transformed the treatment landscape for breast cancer patients. Yet, investigators and regulators must safeguard that highly-priced new drugs demonstrate improvements in patient-centered clinical endpoints: overall survival and quality of life. [ABSTRACT FROM AUTHOR]

Background: Targeted treatment of different types of cancers through highly expressed cancer cell surface receptors by fusion proteins is an efficient method for cancer therapy. The HER2 receptor is a member of the tyrosine kinase receptors family, which plays a notable role in breast cancer tumor development. About 25–30% of breast cancers overexpress human epidermal growth factor receptor 2 (HER2). Methods: In this study, we evaluated the particulars of a designed recombinant protein formed by HER2-specific Mab Herceptin linked with Arazyme on a HER2-overexpressing breast cancer cell line (SKBR3). Arazyme, a metalloprotease produced by Serratia proteamaculans was fused to the variable area of light and heavy chains of the Herceptin. The cytotoxic assay of the Arazyme-linker-Herceptin in the SKBR3 and MDA-MB-468 cells was evaluated by the MTT and flow cytometry techniques. The Caspase‑3 activity determination and adhesion assay were performed to evaluate the antitumor activity of the Arazyme-linker-Herceptin against SKBR3 cells. Furthermore, RT-PCR was used to measure the expression levels of the Bcl-2, Bax, MMP2, MMP9, and RIP3 genes. Results: The Arazyme-linker-Herceptin showed higher cytotoxicity in SKBR3 cells compared to MDA-MB-468 cells. In addition, flow cytometry results revealed that the Arazyme-linker-Herceptin can significantly induce apoptosis in the HER2-overexpressing breast cancer cell line (SKBR3), which was confirmed by Bax upregulation and the decrease in adhesion of tumor cells and MMP2/MMP9. Conclusion: The findings of this study demonstrated that the Arazyme-linker-Herceptin induced apoptosis and decreased metastatic genes in SKBR3 cells; however, further research is required to confirm the effectiveness of the fusion protein. [ABSTRACT FROM AUTHOR]

Objective: To develop a computed tomography (CT) radiomics-based interpretable machine learning (ML) model to preoperatively predict human epidermal growth factor receptor 2 (HER2) status in bladder cancer (BCa) with multicenter validation. Methods: In this retrospective study, 207 patients with pathologically confirmed BCa were enrolled and divided into the training set (n = 154) and test set (n = 53). Least absolute shrinkage and selection operator (LASSO) regression was used to identify the most discriminative features in the training set. Five radiomics-based ML models, namely logistic regression (LR), support vector machine (SVM), k-nearest neighbors (KNN), eXtreme Gradient Boosting (XGBoost) and random forest (RF), were developed. The predictive performance of established ML models was evaluated by the area under the receiver operating characteristic curve (AUC). The Shapley additive explanation (SHAP) was used to analyze the interpretability of ML models. Results: A total of 1218 radiomics features were extracted from the nephrographic phase CT images, and 11 features were filtered for constructing ML models. In the test set, the AUCs of LR, SVM, KNN, XGBoost, and RF were 0.803, 0.709, 0.679, 0.794, and 0.815, with corresponding accuracies of 71.7%, 69.8%, 60.4%, 75.5%, and 75.5%, respectively. RF was identified as the optimal classifier. SHAP analysis showed that texture features (gray level size zone matrix and gray level co-occurrence matrix) were significant predictors of HER2 status. Conclusions: The radiomics-based interpretable ML model provides a noninvasive tool to predict the HER2 status of BCa with satisfactory discriminatory performance. Critical relevance statement: An interpretable radiomics-based machine learning model can preoperatively predict HER2 status in bladder cancer, potentially aiding in the clinical decision-making process. Key Points: The CT radiomics model could identify HER2 status in bladder cancer. The random forest model showed a more robust and accurate performance. The model demonstrated favorable interpretability through SHAP method. [ABSTRACT FROM AUTHOR]

Purpose: To assess whether gray-scale ultrasound (US) based radiomic features can help distinguish HER2 expressions (ie, HER2-overexpressing, HER2-low-expressing, and HER2-zero-expressing) in breast cancer. Materials and Methods: This retrospective study encompassed female breast cancer patients who underwent US examinations at two distinct centers from February 2021 to July 2023. Tumor segmentation and radiomic feature extraction were performed on grayscale US images. Decision Tree analysis was employed to simultaneously evaluate feature importance, and the Least Absolute Shrinkage and Selection Operator technique was utilized for feature selection to construct the radiomic signature. The Area Under the Curve (AUC) of the Receiver Operating Characteristic curve was employed to assess the performance of the radiomic features. Multivariate logistic regression was used to identify independent predictors for distinguishing HER2 expression in the dataset. Results: The training set comprised 292 patients from Center 1 (median, 51 years; interquartile range [IQR]: 45-61), while the external validation set included 131 patients from Center 2 (median, 51 years; IQR: 45-62). In the external validation dataset, the radiomic features achieved AUC of 0.76 for distinguishing between HER2-low and positive tumors versus HER2-zero tumors. The AUC for differentiating HER2-low (1+) from HER2-zero tumors was 0.74, and for distinguishing HER2-low (2+) from HER2-zero tumors, the AUC was 0.77. In the multivariate analysis assessing HER2-low and HER2-positive versus HER2-zero tumors, internal echoes (P =.029) and margins (P <.001) emerged as independent predictive factors. Conclusion: The radiomic signature and tumor descriptors from gray-scale US may predict distinct HER2 expressions of breast cancers with therapeutic implications. [ABSTRACT FROM AUTHOR]

What is this summary about? This is a summary of the publication about the DESTINY-Lung01 study, which was published in the New England Journal of Medicine in September 2021. The DESTINY-Lung01 study includes 181 adults with metastatic non-small-cell lung cancer (NSCLC) that could not be treated with surgery and who have had previous standard anticancer treatment. The publication includes information and results about 91 of the 181 study participants. These 91 participants had HER2-mutant NSCLC. Researchers wanted to learn if the drug trastuzumab deruxtecan (T-DXd) could help treat participants with HER2-mutant NSCLC. At the time of this publication, this study is ongoing. What are the key takeaways? Results from the study showed that 55% of participants responded to treatment with T-DXd. The median length of time participants continued to respond to T-DXd was 9.3 months. After receiving T-DXd, 92% of participants had disease control. After receiving T-DXd, half of the participants lived for at least 17.8 months. After receiving T-DXd, half of the participants lived for 8.2 months before their cancer got worse. During the study, 97% of participants had drug-related adverse events, with nausea being the most common. There were 20% of participants with serious drug-related adverse events. What were the main conclusions reported by the researchers? Based on these results, T-DXd could be a treatment option for people with HER2-mutant NSCLC that has been previously treated. Clinical Trial Registration:NCT03505710 (DESTINY-Lung01) (ClinicalTrials.gov) [ABSTRACT FROM AUTHOR]

Simple Summary: Almost one in five patients with breast cancer have an aggressive subtype that expresses Human Epidermal Growth Factor-2 (HER2) receptor. The introduction of anti-HER2 therapy, like trastuzumab and pertuzumab, has dramatically improved treatment outcomes. However, such therapy is lengthy, costly, and can result in substantial cardiac toxicities. In this review, we discuss ways to de-escalate anti-HER2 therapy by shortening the treatment course to less than the 12-month standard, or minimizing companion chemotherapy. New molecular tools are emerging that should help physicians select which patients with HER2-positive breast cancer benefit most from aggressive and lengthy treatment regimens utilizing single or dual anti-HER2 therapy alone or in combination with chemotherapy. Almost one-fifth of breast cancer cases express Human Epidermal Growth Factor-2 (HER2), and such expression is associated with highly proliferative tumors and poor prognosis. The introduction of anti-HER2 therapies has dramatically changed the natural course of this aggressive subtype of breast cancer. However, anti-HER2 therapy can be associated with substantial toxicities, mostly cardiac, and high cost. Over the past few years, there has been growing interest in de-escalation of anti-HER2 therapies to minimize adverse events and healthcare costs, while maintaining the efficacy of treatment. Data from clinical observations and single-arm studies have eluted to the minimal impact of anti-HER2 therapy in low-risk patients, like those with node-negative and small tumors. Though single-arm, the APT trial, in which patients with node-negative, small tumors received single-agent paclitaxel for 12 cycles plus trastuzumab for 1 year, was a practice-changing study. Several other recently published studies, like the PERSEPHONE trial, have shown more convincing data that 6 months of trastuzumab is not inferior to 12 months, in terms of disease-free survival (DFS), suggesting that de-escalating strategies with shorter treatment may be appropriate for some low-risk patients. Other de-escalating strategies involved an adaptive, response-directed approach, and personalized therapy that depends on tumor genomic profiling. [ABSTRACT FROM AUTHOR]

Anti‐HER2 therapy is indicated for erb‐b2 receptor tyrosine kinase 2 (ERBB2)‐amplified/overexpressing endometrial carcinoma (EC). Mutations constitute another mode of ERBB2 activation, but only rare ERBB2‐mutated ECs have been reported. We sought to characterize the clinicopathologic and genetic features of ERBB2‐mutated EC. From an institutional cohort of 2638 ECs subjected to clinical tumor‐normal panel sequencing, 69 (2.6%) with pathogenic ERBB2 mutation(s) were identified, of which 11 were also ERBB2‐amplified. The most frequent ERBB2 hotspot mutations were V842I (38%) and R678Q (25%). ERBB2 mutations were clonal in 87% of evaluable cases. Immunohistochemistry revealed low HER2 protein expression in most ERBB2‐mutated ECs (0/1+ in 66%, 2+ in 27%); all 3+ tumors (7.3%) were also ERBB2‐amplified. Compared to ERBB2‐wildtype ECs (with or without ERBB2 amplification), ERBB2‐mutated/non‐amplified ECs were enriched for the microsatellite instability‐high (MSI‐H) and, to a lesser extent, DNA polymerase epsilon, catalytic subunit (POLE) molecular subtypes, and associated with high tumor mutational burden and low chromosomal instability. Survival outcomes were similar between patients with ERBB2‐mutated/non‐amplified versus wildtype EC, whereas ERBB2 amplification was associated with worse prognosis on univariate, but not multivariate, analyses. In conclusion, ERBB2 mutation defines a rare subgroup of ECs that is pathogenically distinct from ERBB2‐wildtype and ERBB2‐amplified ECs. [ABSTRACT FROM AUTHOR]

Background: Today, breast cancer is the most diagnosed cancer worldwide. There are many different clinical presentations, radiological characteristics, and histological types of breast cancer. HER2 is overexpressed in a significant number of breast cancer cases reaching 20% of all breast cancers, and its overexpression is seen directly proportionate with a poor outcome and prognosis. Methods: We started this cross-sectional research from January 2022–December 2023 on 202 breast cancer patients who had 220 lesions. The molecular subtypes of the different lesions were determined in all the included cases. Magnetic resonance imaging (MRI) studies were conducted in all included cases. The MRI parameters included conventional MRI, diffusion-weighted analysis, and dynamic post-contrast T1-weighted imaging. Results: The prevalence of irregular margins (P < 0.001), linear and segmental distribution (P = 0.044), heterogeneous pattern (P < 0.001), and type 2 curve was statistically significantly higher in the HER2-positive lesions. Nipple infiltration incidence showed statistically significant elevation in the HER2-positive lesions (P = 0.017). The lesions' ADC and perilesional ADC in the HER2-positive lesions were also statistically significantly elevated. The best cutoff point of ADC to detect lesions with positive HER2 expression was > 0.885 × 10–3 mm2/s, with 65.7% sensitivity and 60% specificity, with a statistically significant value (p = 0.005). Conclusions: Magnetic resonance imaging of breast imaging is a promising noninvasive method for identifying breast tumors with the HER2 molecular subtype. Combining various radiological features by MRI may provide a conclusion for recognizing positive HER2 lesions. [ABSTRACT FROM AUTHOR]

There is limited research on the clinicopathological characteristics of combined hepatocellular-cholangiocarcinoma (cHCC-CCA) currently. The aim of this study is to summerize the clinicopathological factors and prognosis of cHCC-CCA, which could help us understand this disease. 72 cases of cHCC-CCA from West China Hospital of Sichuan University were collected. Tissue components were reviewed by pathologists. Immunohistochemistry was used to detect the status of mismatch repair (MMR) and human epidermal growth factor receptor 2 (HER2) in cHCC-CCA, as well as the quantity and distribution of CD3+ T cells and CD8+ T cells. Fluorescence in situ hybridization was used to detect fibroblast growth factor receptor 2 (FGFR2) gene alteration. COX univariate and multivariate analyses were used to evaluate risk factors, and survival curves were plotted. 49 cases were classified as classic type cHCC-CCA and 23 cases as intermediate cell carcinoma. The cut-off value for diagnosing classic type was determined to be ≥ 30% for the cholangiocarcinoma component based on prognostic calculations. All tumors were MMR proficient. The rate of strong HER2 protein expression (3+) was 8.3%, and the frequency of FGFR2 gene alteration was 26.4%. CD3+ T cells and CD8+ T cells were mainly distributed at the tumor margin, and were protective factors for patients with cHCC-CCA. The overall survival of the 72 patients was 18.9 months, with a median survival of 12 months. Tumor size, TNM stage, and serum AFP level were prognostic factors for cHCC-CCA. The proportion of cholangiocarcinoma component reaching the threshold of 30%, may provide a reference for future pathology diagnosis. FGFR2 gene alteration was 26.4%, providing a clue for anti-FGFR2 therapy. However, more data is needed for further verification. [ABSTRACT FROM AUTHOR]

Purpose: Varlitinib is a pan-human epidermal growth factor receptor (HER) inhibitor targeting epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (HER2), and HER4. We present a phase Ib/II study of a combination of varlitinib and weekly paclitaxel as a second-line treatment for patients with EGFR/HER2 co-expressing advanced gastric cancer (AGC). Materials and Methods: Patients whose tumors with EGFR and HER2 overexpression by immunohistochemistry (≥ 1+) were enrolled. Varlitinib and paclitaxel were investigated every 4 weeks. After determining the recommended phase II dose (RP2D) in phase Ib, a phase II study was conducted to evaluate the antitumor activity. Results: RP2D was treated with a combination of varlitinib (300 mg twice daily) and paclitaxel. Among 27 patients treated with RP2D, the median progression-free survival and overall survival (OS) were 3.3 months (95% confidence interval [CI], 1.7 to 4.9) and 7.9 months (95% CI, 5.0 to 10.8), respectively, with a median follow-up of 15.7 months. Among 16 patients with measurable disease, the objective response rate (ORR) and disease control rate were 31% and 88%, respectively. Patients with strong HER2 expression (n=8) had a higher ORR and longer OS, whereas those with strong EGFR expression (n=3) had poorer outcomes. The most common adverse events (AEs) of any grade were neutropenia (52%), diarrhea (27%), aspartate aminotransferase/alanine transaminase elevation (22%), and nausea (19%). No treatment-related deaths or unexpected AEs resulting from treatment cessation were observed in patients with RP2D. Conclusion: A combination of varlitinib and paclitaxel displayed manageable toxicity and modest antitumor activity in patients with EGFR/HER2 co-expressing AGC who progressed after first-line chemotherapy. [ABSTRACT FROM AUTHOR]

The 25th Annual Western Canadian Gastrointestinal Cancer Consensus Conference (WCGCCC) was held in Winnipeg, Manitoba, on 26–27 October 2023. The WCGCCC is an interactive multidisciplinary conference that was attended by healthcare professionals from across Western Canada (British Columbia, Alberta, and Manitoba) who are involved in the care of patients with gastrointestinal cancer. Surgical, medical, and radiation oncologists; pathologists; oncology nurses; pharmacists; and a family physician in oncology (FPO) participated in presentation and discussion sessions for the purpose of developing the recommendations presented here. This consensus statement addresses current issues in the management of gastroesophageal cancers. [ABSTRACT FROM AUTHOR]

Leptomeningeal carcinomatosis (LMC) is a devastating complication of advanced cancers, such as lung cancer and breast cancer, which is usually indicative of a poor prognosis. The current treatments for LMC include palliative care, with others aiming to prolong survival and relieve neurological symptoms. Traditional treatments for LMC include radiotherapy, systemic chemotherapy, and intrathecal injection. Furthermore, the application of molecularly targeted agents, such as antiepidermal growth factor receptor (anti‐EGFR), antihuman epidermal growth factor receptor 2 (anti‐HER2), and anti‐PD‐1 monoclonal antibody, have prolonged the survival of LMC patients. Targeted therapy with tyrosine kinase inhibitors has also been proven to be an effective treatment. Tyrosine kinases can be overactive or expressed at high levels in some cancer cells; therefore, the use of tyrosine kinase inhibitors may prevent the activation of tumor‐related pathways, preventing cancer cell growth. The EGFR family are cell surface receptors directly related to tumor occurrence with tyrosine kinase activity; it is the most widely used target for tyrosine kinase inhibitors in the treatment of LMC. In this review, we introduced the clinical manifestation and diagnostic criteria of LMC, clarified the treatment mechanism of tyrosine kinase inhibitors for LMC with mutations in EGFR, HER2, or anaplastic lymphoma kinase, reviewed the current application of various generation tyrosine kinase inhibitors in patients with LMC, and discussed new clinical trials and the future directions of tyrosine kinase inhibitor therapy. [ABSTRACT FROM AUTHOR]

Simple Summary: Male breast cancer (MBC) is a rare condition, and the role of low HER2 expression (HER2 low) is not well understood. In this prospective study, 870 MBC patients treated between May 2009 and June 2023 were evaluated to investigate the prognostic significance of HER2 low status. After a median follow-up of 43 months, 659 patients were classified into three groups: 76% were HER2 low, 12.3% were HER2 zero, and 11.7% were HER2 positive. HER2 positivity was linked to younger age, higher tumor proliferation, and more aggressive cancer characteristics, but no differences were found between HER2 zero and HER2 low groups. Furthermore, HER2 low status did not influence disease-free or overall survival. However, HER2 low has a potential clinical impact on MBC as a treatment target. Background: Male breast cancer (MBC) is a rare disease, and the potential influence of low expression of human epidermal growth factor receptor 2 (HER2 low) remains unexplored. Methods: In this prospective cohort study, we evaluated 870 patients treated for MBC between May 2009 and June 2023 to assess HER2 low status and its prognostic implications. Results: With a median follow-up of 43 months (range 1–175 months), 659 eligible patients were categorized into three groups based on HER2 status: 501 (76%) HER2 low, 81 (12.3%) HER2 zero, and 77 (11.7%) HER2 positive. HER2 positivity correlated with younger age, higher proliferation index, non-specific type histology, lymphovascular invasion (LVSI), and low differentiation grade. Notably, all these parameters were equally distributed between the HER2 zero and HER2 low groups. Additionally, HER2 positivity was significantly associated with increased occurrences of regional and distant lymph nodes and pulmonary metastases. However, no statistically significant difference was observed between HER2 zero and HER2 low. Disease-free and overall survival showed no significant disparities between the groups. Conclusions: Our findings suggest that HER2 low status is frequently detected in MBC. Despite this, HER2 low did not correlate with clinical and pathological parameters, nor did it impact patients' survival. [ABSTRACT FROM AUTHOR]

Simple Summary: A review of the latest research at PubMed and major cancer conferences was conducted to find out the current treatments for advanced stomach and esophagogastric junction cancers. In the West, neoadjuvant and perioperative chemotherapy is preferred for localized tumors. In East Asia, adjuvant chemotherapy is preferred. Studies are looking at how well immunotherapy and other drugs work in the perioperative setting. To choose the best treatment for advanced gastric cancer, including adenocarcinoma of the esophago-gastric junction, it is important to know biomarkers like HER2 expression, PD-L1 combined positive score (CPS), Claudin 18.2, and microsatellite instability (MSI). The standard first-line therapy is a combination of fluoropyrimidine and a platinum derivative. The choice of chemotherapy with antibodies depends on the biomarker. This article reviews recent clinical trial results and looks at the future of systemic therapy. 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. [ABSTRACT FROM AUTHOR]

Simple Summary: HER2 is a well-known driver of worse outcomes for many types of cancer, including prostate cancer. While HER2 has been previously evaluated in prostate cancer bench studies and clinical trials, there has been a lack of diversity in the experimental designs and protocols. For this reason, it has only recently been reported that Black men with prostate cancer may have a higher prevalence of HER2 overexpression. To thoroughly address health inequities that exist for Black men with prostate cancer, it is critical to utilize diverse biospecimens and enroll diverse study participants into studies that evaluate genetic and molecular contributors to worse prognosis for high-risk populations. In this review, we reconsider the role of HER2 in prostate cancer with an approach that incorporates the effects of race and genetic ancestry. Human epidermal growth factor receptor 2 (HER2) is a major driver of disease progression, treatment resistance, and worse survival for patients with various types of cancers, including prostate cancer. However, key bench studies and clinical trials have failed to evaluate the role of HER2 in prostate cancer using racially diverse experimental designs and protocols. This lack of diversity represents what has been the status quo of cancer research in the United States for decades. In the case of prostate cancer, homogenic study designs are problematic as Black men are much more likely to be diagnosed and die from aggressive and incurable forms of the disease. Therefore, the strategic inclusion of biospecimens collected from Black patients as well as the recruitment and enrollment of Black men into prostate cancer clinical trials is necessary to comprehensively evaluate genetic and molecular factors that contribute to variable outcomes in this high-risk population. Additionally, a higher prevalence of HER2 expression in Black men was recently reported in a small cohort of prostate cancer patients and may contribute to worsened prognosis. In this review, we carefully consider the role of HER2 in prostate cancer while, for the first time, taking into account the influences of race and genetic ancestry. [ABSTRACT FROM AUTHOR]

Human epidermal growth factor receptor 2 (HER2) is known for its oncogenic activities in diverse cancers, including non-small cell lung cancer (NSCLC). However, the prevalence of HER2 alterations in Malaysian NSCLC patients remains unreported. This study examined the prevalence and characteristics of HER2 mutations and amplification in a Malaysian cohort. Additionally, a systematic review was conducted to evaluate the global prevalence of HER2 alterations in NSCLC, as well as the efficacy of HER2-targeted therapies observed in clinical trials. NSCLC tumour samples received from October 2019 to December 2022 for next-generation sequencing diagnostics were included in the retrospective analysis. In this patient cohort, HER2 alteration was present in 5.8% of patients; 3.9% had HER2 mutations, 1.5% had HER2 amplifications and 0.4% were both HER2-mutated and amplified. HER2 exon 20 insertions were the most common HER2 variants, detected in 47/59 (79.7%) of HER2-mutated patients. Among cases with HER2 exon 20 insertions, the Y772&lowbar;A775dup variant was found in 34 patient samples. HER2-mutated patients were significantly younger than non-HER2-mutants (61 versus 64 years old; p = 0.046) and were inclined to be female and never-smokers, albeit not statistically significant. Patients with HER2 amplification were more likely to have progressed post-tyrosine kinase inhibitor therapy (p = 0.015). The systematic review highlighted a global variation in the prevalence of HER2 alterations in NSCLC, ranging from 0.3% to 9.1% for mutations and 0.2% to 19% for amplification. Finally, phase II clinical trials involving HER2-altered NSCLC patients demonstrated promising treatment outcomes with trastuzumab deruxtecan, trastuzumab emtansine, pyrotinib, pyrotinib + apatinib and trastuzumab + pertuzumab + docetaxel. In conclusion, the prevalence of HER2 alteration among Malaysian NSCLC patients falls within the global range. A systematic review of clinical trials revealed promising treatment outcomes and Malaysian NSCLC patients with HER2 alterations are anticipated to similarly benefit from HER2-targeted therapies. [ABSTRACT FROM AUTHOR]

A next generation multiscale quantitative systems pharmacology (QSP) model for antibody drug conjugates (ADCs) is presented, for preclinical to clinical translation of ADC efficacy. Two HER2 ADCs (trastuzumab-DM1 and trastuzumab-DXd) were used for model development, calibration, and validation. The model integrates drug specific experimental data including in vitro cellular disposition data, pharmacokinetic (PK) and tumor growth inhibition (TGI) data for T-DM1 and T-DXd, as well as system specific data such as properties of HER2, tumor growth rates, and volumes. The model incorporates mechanistic detail at the intracellular level, to account for different mechanisms of ADC processing and payload release. It describes the disposition of the ADC, antibody, and payload inside and outside of the tumor, including binding to off-tumor, on-target sinks. The resulting multiscale PK model predicts plasma and tumor concentrations of ADC and payload. Tumor payload concentrations predicted by the model were linked to a TGI model and used to describe responses following ADC administration to xenograft mice. The model was translated to humans and virtual clinical trial simulations were performed that successfully predicted progression free survival response for T-DM1 and T-DXd for the treatment of HER2+ metastatic breast cancer, including differential efficacy based upon HER2 expression status. In conclusion, the presented model is a step toward a platform QSP model and strategy for ADCs, integrating multiple types of data and knowledge to predict ADC efficacy. The model has potential application to facilitate ADC design, lead candidate selection, and clinical dosing schedule optimization. [ABSTRACT FROM AUTHOR]

High-grade serous ovarian cancer (HGSOC) and ovarian clear cell carcinoma (CC), are biologically aggressive tumors endowed with the ability to rapidly metastasize to the abdominal cavity and distant organs. About 10% of HGSOC and 30% of CC demonstrate HER2 IHC 3 + receptor over-expression. We evaluated the efficacy of trastuzumab deruxtecan (T-DXd; DS-8201a), a novel HER2-targeting antibody-drug conjugate (ADC) to an ADC isotype control (CTL ADC) against multiple HGSOC and CC tumor models. Eleven ovarian cancer cell lines including a matched primary and metastatic cell line established from the same patient, were evaluated for HER2 expression by immunohistochemistry and flow cytometry, and gene amplification by fluorescence in situ hybridization assays. In vitro experiments demonstrated T-DXd to be significantly more effective against HER2 3 + HGSOC and CC cell lines when compared to CTL ADC (p < 0.0001). T-DXd induced efficient bystander killing of HER2 non-expressing tumor cells when admixed with HER2 3 + cells. In vivo activity of T-DXd was studied in HER2 IHC 3 + HGSOC and CC mouse xenograft models. We found T-DXd to be significantly more effective than CTL ADC against HER2 3 + HGSOC (KR(CH)31) and CC (OVA10) xenografts with a significant difference in tumor growth starting at day 8 (p = 0.0003 for KR(CH)31, p < 0.0001 for OVA10). T-DXd also conferred a survival advantage in both xenograft models. T-DXd may represent an effective ADC against primary and metastatic HER2-overexpressing HGSOC and CC. [ABSTRACT FROM AUTHOR]

Metastatic disease results from the dissemination of tumor cells beyond their organ of origin to grow in distant organs and is the primary cause of death in patients with advanced breast cancer. Preclinical murine models in which primary tumors spontaneously metastasize are valuable tools for studying metastatic progression and novel cancer treatment combinations. Here, we characterize a novel syngeneic murine breast tumor cell line that provides a model of spontaneously metastatic neu-expressing breast cancer with quicker onset of widespread metastases after orthotopic mammary implantation in immune-competent NeuN mice. The NT2.5-lung metastasis (-LM) cell line was derived from serial passaging of tumor cells that were macro-dissected from spontaneous lung metastases after orthotopic mammary implantation of parental NT2.5 cells. Within one week of NT2.5-LM implantation, metastases are observed in the lungs. Within four weeks, metastases are also observed in the bones, spleen, colon, and liver. We demonstrate that NT2.5-LM metastases are positive for NeuN—the murine equivalent of human epidermal growth factor 2 (HER2). We further demonstrate altered expression of markers of epithelial-to-mesenchymal transition (EMT), suggestive of their enhanced metastatic potential. Genomic analyses support these findings and reveal enrichment in EMT-regulating pathways. In addition, the metastases are rapidly growing, proliferative, and responsive to HER2-directed therapy. The new NT2.5-LM model provides certain advantages over the parental NT2/NT2.5 model, given its more rapid and spontaneous development of metastases. Besides investigating mechanisms of metastatic progression, this new model may be used for the rationalized development of novel therapeutic interventions and assessment of therapeutic responses. [ABSTRACT FROM AUTHOR]

Abstract Human epidermal growth factor receptor 2 (HER2) overexpression emerges as an attractive therapeutic target in gynecological malignancies. Recently, Trastuzumab-Deruxtecan (T-DXd) has shown substantial efficacy in HER2 overexpressing carcinomas, most prominently in ovarian, endometrial and cervical patients. We have examined the efficacy of T-DXd in patients with metastatic endometrial, ovarian and cervical malignancies that were treated in the Department of Clinical Therapeutics, Alexandra Hospital, School of Medicine, National and Kapodistrian University of Athens. Methods Patients with gynecological malignancies with HER2 expression 2 + /3 + as assessed by immunohistochemistry (IHC) that were treated with T-DXd were retrospectively identified. Patients received T-DXd intravenously at a dose of 5.4 mg/kg every 3 weeks until disease progression or unacceptable toxicity. Results In total, 10 patients treated with T-DXd for recurrent/metastatic disease were identified. Regarding histology, there were 5 patients with uterine neoplasms (serous carcinoma (n = 3), uterine carcinosarcoma (n = 1), uterine leiomyosarcoma (n = 1)), 1 patient with squamous cervical carcinoma and 4 patients with ovarian cancer (ovarian carcinosarcoma (n = 2), high-grade serous carcinoma (n = 1) and mucinous ovarian carcinoma (n = 1)). Median age was 65.4 years (25th-75th percentile, 58.1–75.2 years). 5 patients had HER2 expression 3 + by IHC and 5 patients had HER2 expression 2 + . Median number of previous lines of therapy was 4 (range 2–6), 2 patients with uterine serous carcinoma were pretreated with trastuzumab and 4 patients had already received immunotherapy. In the entire cohort median progression-free survival (PFS) was 5.4 months (95%CI 0.8–9.8 months). Regarding responses, 5 patients had partial response (including 2 patients that were pretreated with trastuzumab), 1 patient had stable disease at 12 weeks and 4 patients had disease progression at initial assessment. All patients but one that derived clinical benefit had HER2 3 + expression. Discussion In the real-world setting, T-DXd showed activity in a cohort of heavily pre-treated patients with HER2-expressing gynecological malignancies.

Abstract Background Human epidermal growth factor receptor 2-targeted (HER2) therapy with antibody-drug conjugates has proven effective for patients with HER2-low breast cancer. However, intratumoral heterogeneity (ITH) poses a great challenge in identifying HER2-low tumors. ITH signatures were developed by quantifying ITH to differentiate HER2-positive, -low and -zero breast cancers. Methods This retrospective study included 614 patients from two institutions. The study was structured into two primary tasks: task 1 was to differentiate between HER2-positive and -negative tumors, followed by task 2 to differentiate HER2-low and -zero tumors. Whole-tumor radiomics features and habitat radiomics features were extracted from MRI to construct the radiomics and ITH signatures. Multivariable logistic regression analysis was used to determine significant independent predictors. A combined model integrating significant clinicopathologic variables, radiomics signature, and ITH signature was developed for task (1) Subsequently, the better-performing model was established using the same approach for task (2) The area under the receiver operating characteristic curve (AUC) was used to assess the performance of each model. Results Task 1 comprised 614 patients (training, n = 348; validation, n = 149; and test cohorts, n = 117). Task 2 encompassed 501 patients (training, n = 283; validation, n = 122; and test cohorts, n = 96). For task1, the ITH signature showed outstanding performance, achieving AUCs of 0.81, 0.81, and 0.81 in the training, validation and test cohorts, respectively. The combined model achieved improved performance, with AUCs of 0.83, 0.84 and 0.83 across the three cohorts, respectively. For task2, the ITH signature maintained superior performance, with AUCs of 0.94, 0.93 and 0.84 across the training, validation and test cohorts, respectively. Multivariable logistic regression analysis indicated that none of the clinicopathologic characteristics were retained as predictors associated with odds of HER2-low tumors. Conclusions Our study developed ITH signatures that quantified ITH using habitat-based MRI radiomics, achieving outstanding performance in differentiating HER2-postive and -negative tumors, and further differentiating HER2-low and -zero breast cancers.

Abstract Background Colorectal cancer (CRC) is a leading cause of cancer-related mortality, highlighting the necessity for multifaceted treatment strategies, including preoperative treatment (PT), which can enhance surgical outcomes and provide prognostic insights. This study aims to clarify the impact of PT-induced changes in mismatch repair (MMR) and human epidermal growth factor receptor 2 (HER2) expression, potentially informing tailored treatment strategies and improving clinical outcomes for CRC patients. Methods This retrospective study analyzed 120 paired samples from CRC patients who underwent preoperative treatment, comparing pre- and post-treatment specimens. A control group of 60 untreated surgical specimens was also included. Immunohistochemistry assessed MMR proteins (MSH6, MSH2, MLH1, PMS2) and HER2 expression. MSI status was determined in samples with low MMR expression. Results Compared to pre-treatment samples, post-treatment samples exhibited lower levels of MSH6, MSH2, and total MMR expression, along with higher levels of HER2 expression. However, when compared to the untreated control group, there were no significant differences in the expression of MSH6, total MMR, and HER2. All samples that exhibited weak MMR expression and those that shifted to deficient mismatch repair (dMMR) status following treatment had stable microsatellite status. No clear clinicopathological characteristics or prognostic factors were found to be associated with changes in MMR and HER2 expression, except for the use of fluorouracil or capecitabine, which was related to changes in total MMR scores. ypTNM stage and TRG scores were identified as independent factors affecting disease progression in our study. Conclusions PT is associated with a reduction in MMR expression, notably for the MSH2 protein, while it does not appear to influence HER2 expression.