Antibody-drug conjugates, particularly trastuzumab deruxtecan (T-DXd), have emerged as effective therapies for various solid tumours. Clinical trials show that T-DXd improves survival in both HER2-positive and HER2-low breast cancer patients. Additionally, it improves survival in HER2-positive gastro-oesophageal cancer and elicits objective responses in HER2-low tumours. Responses have also been noted in lung and gynaecological cancers with HER2 expression, although subgroup analyses for HER2-low cases are lacking. This review assesses HER2 protein expression levels and gene amplification across solid tumours where T-DXd shows potential benefits. We focus on the accuracy and limitations of HER2 testing methods, particularly for identifying HER2-low cancer. A semi-systematic approach was employed, searching EMBASE, Medline, Cochrane, and PubMed databases. We calculated median incidences of HER2-positive, HER2-low, and HER2-0 by immunohistochemistry (IHC), and HER2 amplification by in situ hybridisation (ISH). A total of 144 studies were included, covering breast (n=57), gastro-oesophageal (n=33), lung (n=17), gynaecological (n=24), and various other carcinomas (n=13). The median incidences of HER2-low were 52%, 16%, 58%, and 17% in breast, gastro-oesophageal, endometrial, and ovarian cancers, respectively, with unknown incidences in lung and cervical cancers. Factors influencing HER2-low detection include tumour heterogeneity, antibody clones, observer variability, and lack of validated scoring criteria. Given the significant proportion of HER2-low cases, many patients could benefit from T-DXd, but limitations in detection accuracy necessitate further research and standardisation in diagnostic methods and criteria to advance the clinical utility of T-DXd for HER2-low tumours.

Human epidermal growth factor receptor 2 (HER2; encoded by ERBB2) testing has been a cornerstone of patient selection for HER2-targeted therapies, principally in breast cancer but also in several other solid tumours. Since the introduction of HercepTest as the original companion diagnostic for trastuzumab, HER2 assessment methods have evolved substantially, incorporating various testing modalities, from western blots, immunohistochemistry and fluorescence in situ hybridization, to early chromogenic quantitative methods and, probably in the future, fully quantitative methods. The advent of highly effective HER2-targeted antibody-drug conjugates with clinical activity at low levels of HER2 expression, such as trastuzumab deruxtecan, has necessitated the re-evaluation of HER2 testing, particularly for HER2-low tumours. In this Review, we provide an in-depth overview of the evolution of HER2 testing, the current clinical guidelines for HER2 testing across various solid tumours, challenges associated with current testing methodologies and the emerging potential of quantitative techniques. We discuss the importance of accurately defining HER2-low expression for therapeutic decision-making and how newer diagnostic approaches, such as quantitative immunofluorescence and RNA-based assays, might address the limitations of traditional immunohistochemistry-based methods. As the use of HER2-targeted therapies continues to expand to a wider range of tumour types, ensuring the precision and accuracy of HER2 testing will be crucial for guiding treatment strategies and improving patient outcomes.

HER2 is a membrane receptor tyrosine kinase overexpressed in 18-20% of gastric tumors. Trastuzumab emtansine (T-DM1) is an antibody-drug conjugate (ADC) that targets HER2-positive (HER2+) cancer cells with a chemotherapeutic agent, emtansine. T-DM1 has low efficacy in HER2+ gastric cancer. This study explored the efficacy of combining drugs known to modulate HER2 internalization to enhance T-DM1 efficacy in gastric cancer. We used cholesterol-depleting drugs (lovastatin) to enhance HER2 membrane density. The irreversible pan-HER tyrosine kinase inhibitor neratinib was used to enhance the internalization of HER2-bound T-DM1. Therapy, pre-treatment and post-treatment positron emission tomography/computed tomography (PET/CT) were performed in both male and female mice. An enhancement of cell surface and internalized HER2 was observed after lovastatin and neratinib incubations, respectively. The combination of lovastatin with neratinib enhanced T-DM1 internalization in cancer cells. A decrease in HER2 protein levels and HER2 phosphorylation was detected in cells treated with T-DM1/lovastatin/neratinib when compared to control and T-DM1-only groups. PET/CT imaging of mice in the T-DM1/lovastatin/neratinib group showed a decrease in HER2 tumoral expression, which was associated with a decrease in tumor volume and sustained treatment efficacy in the T-DM1/lovastatin/neratinib group. This work demonstrates the therapeutic enhancement of T-DM1 using combination therapy with lovastatin/neratinib in gastric cancer. The treatment can be successfully monitored through PET/CT imaging.

Recently, a new type of antibody-drug conjugate, trastuzumab-deruxtecan (T-DXd), has been approved for the treatment of metastatic breast cancer with low level of human epidermal growth factor receptor 2 (HER2) gene expression. Thereby, eligibility relies on an accurate diagnosis of HER2-low status defined by immunohistochemistry IHC 1+/2+ with no gene amplification.

To assess pathologists' accuracy and training efficacy in the diagnosis of HER2-low.

Agreement rates of HER2-low scoring in breast cancer tissue were assessed between expert consensus and real-world pathologists (n = 77 from 14 countries) before and after a specific 4-hour training program for HER2-low detection. Two assays were evaluated, the Ventana Pathway 4B5 CDx and the Dako HercepTest (polyclonal). Concordance of the pathologists with consensus score and efficacy of training were measured by Cohen κ, overall rater agreement, and receiver operating characteristic (ROC) curve statistics.

In the Ventana 4B5 HER2-low category, baseline agreement rates were >80% but <90%. Negative percentage agreement was improved from 80.6% to 91.1% by training. In the HER2-0 category, positive percentage agreement (74.6%) was the only parameter below the 80% benchmark but was significantly improved to 89.2% after training. Training efficacy was confirmed by ROC curve analysis, which shows improvement for the identification of HER2-0 and HER2-low cases. Finally, in-depth examination of cases with discordant HER2 status disclosed specific issues of HER2-low underscoring and overscoring.

The ability of pathologists to achieve acceptable diagnostic accuracy in identifying patients with HER2-low breast cancer could be enhanced by short-term training. Potential routes to improve the quality of HER2-low scoring in clinical practice have been identified.

Gastric cancer (GC) is a deadly disease worldwide, and trastuzumab in combination with chemotherapy has been the standard first-line treatment for HER2-positive GC following the TOGA trial. Besides adjuvant therapy, HER2-directed therapy is widely used as neoadjuvant or translational therapy, and survival benefit even surgical opportunities is seen in these patients. However, resistance is not rare in recent years, and the second-line treatment for trastuzumab beyond progression has received widespread attention in GC. Moreover, current evidence cannot recommend trastuzumab for patients with IHC1+ HER2 low expression GC yet. Researchers are currently investigating whether GC patients with low HER2 expression could also benefit from HER2-directed therapies. In addition to using HER2 as a target for targeted therapy, HER2-mediated targeted delivery of cytotoxic drugs and targeted immunity have made important contributions to overcoming trastuzumab resistance in recent trials. HER2/neu-derived peptide epitopes vaccination and HER2-specific chimeric antigen receptor (CAR) therapy focus on reestablishing anti-tumor immunity in different ways and show significant anti-tumor activity. Other antibodies that target different regions of the HER2 receptor or block key downstream pathways such as AKT or PI3K also offer potential anti-tumor activity against HER2. HER2 use in GC will not be hampered by resistance or low expression and will play a bigger role. We review the current efforts to enable GC patients with trastuzumab-resistant and HER2 low-expressing accessible to HER2 targeted therapy and present our consideration for future HER2 in GC.

Gastroesophageal carcinomas, including gastroesophageal adenocarcinoma (GEA) and esophageal squamous cell carcinoma (ESCC), pose a global health challenge due to their heterogeneity. The approach to diagnosis and treatment should first differentiate between GEA and ESCC. Over the past decade, therapies for metastatic or advanced GEA/ESCC have expanded, with several new therapeutic targets alongside trastuzumab for metastatic HER2-positive GEA. Four key biomarkers are essential for targeted therapy: HER2 overexpression/amplification, deficient mismatch repair/microsatellite instability (dMMR/MSI), PD-L1, and Claudin18.2 expression. Immunohistochemistry is the recommended method for these biomarkers evaluation. In addition, the assessment of biomarkers like FGFR2b is likely to become routine in the near future. Experts from the Spanish Society of Pathology (SEAP) and the Spanish Society of Medical Oncology (SEOM) have formed a consensus to optimize biomarker detection and usage in clinical practice. Their recommendations aim to improve personalized treatment strategies for GEA and ESCC patients, integrating new diagnostic insights into routine care.

HER2-positive gastric cancer (GC), a unique molecular subtype, has garnered significant interest in recent years. Here, we review clinical trial data on advanced HER2-positive GC from the past 15 years. Trastuzumab plus standard chemotherapy remain the first-line treatment. The initial survival benefits conferred by immune checkpoint inhibitors plus trastuzumab and standard chemotherapy are encouraging. The combination of ramucirumab and mono-chemotherapy, as well as the antibody conjugated drug trastuzumab deruxtecan, is the recommended second-line regimen. Treatment with immune checkpoint inhibitors plus ramucirumab and mono-chemotherapy shows promise. Despite the limited treatment options for third line and beyond, development of novel therapeutic strategies is expected. Although clinical cure of advanced HER2-positive GC is unlikely, current clinical studies offer valuable insight into regimens that prolong survival.

Biliary tract cancers (BTCs) are a wide class of malignancies with dismal prognosis. The therapeutic scenario of metastatic BTCs has profoundly changed during recent years. The combination of cisplatin-gemcitabine plus immunotherapy is currently the gold standard in the first line. The more extensive comprehension of the mechanisms at the basis of BTCs and the identification of several molecular alterations has led to the introduction of target-directed therapies in the second line and beyond that have expanded the therapeutic armamentarium alongside the standard FOLFOX regimen, and for the near future, the results of some trials with targeted therapies in first line are expected. HER2 represents a promising therapeutic target detected in BTCs, being overexpressed in approximately 15-20% of cases, with a strong predilection for gallbladder carcinoma and extrahepatic cholangiocarcinoma, although a small proportion of HER2 overexpression can be detected even in intrahepatic cholangiocarcinoma. The efficacy and safety of different HER2 inhibitors have been investigated in several studies in the second line and beyond with encouraging results. This comprehensive review is intended to provide a summary of existing evidence and future perspectives on HER2 altered BTCs.

Anti-human epidermal growth factor receptor-2 (Her-2/neu) target therapy has substantially improved the disease outcome of patients with breast and gastric/gastroesophageal cancers characterized by Her-2/neu overexpression and/or amplification. Consequently, evaluating Her-2/neu expression in other cancers to predict response to Her-2/neu targeting agents emerges as a crucial approach. We aimed at investigating the positivity rate of this receptor in gallbladder cancer (GBC) and assess the relationship between Her-2/neu status, clinicopathological parameters and survival to identify patients who would benefit most from anti-Her-2/neu-targeted therapy. The Her-2/neu expression was correlated with clinicopathological parameters and survival of GBC cases.

Total 235 surgically resected and histopathologically proven primary GBC cases were collected over a five-year period from January 1, 2017, to December 31, 2020. Her-2/neu expression in these cases was analyzed using immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH).

Employing testing algorithms (IHC scoring based on gastric cancer criteria, followed by FISH in equivocal cases), Her-2/neu positivity was identified in 43 (18.29%) GBC cases and was significantly associated with grade-I tumors, tumor stage > T2, perineural invasion, surgical margin positivity and advanced Tumor-Node-Metastasis (TNM) stage. The mean survival time for Her-2/neu-positive cases was 14 months (SE, 1.1; 95% CI, 11.7-16.06), while it was 20 months (SE, 0.69; 95%CI, 18.1-20.9) for Her-2-negative cases (p < 0.001).

Her-2/neu is expressed in about one-fifth of GBC patients and is significantly associated with tumor behavior and patient survival. Utilizing novel targeted agents may hold the key to improving the prognosis of these patients.

4-1BB (CD137) is a costimulatory immune receptor expressed on activated T cells, activated B cells, NK cells, and tumor-infiltrating lymphocytes, making it a promising target for cancer immunotherapy. Cinrebafusp alfa, a monoclonal antibody-like bispecific protein targeting HER2 and 4-1BB, aims to localize 4-1BB activation to HER2-positive tumors. This study evaluated the safety, tolerability, and preliminary efficacy of cinrebafusp alfa in patients with previously treated HER2-positive malignancies.

This was a multicenter dose-escalation study involving patients with HER2-positive malignancies who received prior treatment. The study assessed the safety and efficacy of cinrebafusp alfa across various dose levels. Patients were assigned to different cohorts, and antitumor responses were evaluated. The study aimed to determine the MTD and to observe any clinical activity at different dose levels.

Of 40 evaluable patients in the "active dose" efficacy cohorts, five showed an antitumor response, resulting in an overall response rate of 12.5% and a disease-control rate of 52.5%. Clinical activity was observed at the 8 and 18 mg/kg dose levels, with confirmed objective response rates of 28.6% and 25.0%, respectively. Cinrebafusp alfa was safe and tolerable, with grade ≤2 infusion-related reactions being the most frequent treatment-related adverse event. MTD was not reached during the study.

Cinrebafusp alfa demonstrates promising activity in patients with HER2-positive malignancies who have progressed on prior HER2-targeting regimens. Its acceptable safety profile suggests it could be a treatment option for patients not responding to existing HER2-directed therapies. See related commentary by Eguren-Santamaría et al., p. 231.

Cancers of the digestive system are major contributors to global cancer-associated morbidity and mortality, accounting for 35% of annual cases of cancer deaths. The etiologies, molecular features, and therapeutic management of these cancer entities are highly heterogeneous and complex. Over the last decade, genomic and functional studies have provided unprecedented insights into the biology of digestive cancers, identifying genetic drivers of tumor progression and key interaction points of tumor cells with the immune system. This knowledge is continuously translated into novel treatment concepts and targets, which are dynamically reshaping the therapeutic landscape of these tumors. In this review, we provide a concise overview of the etiology and molecular pathology of the six most common cancers of the digestive system, including esophageal, gastric, biliary tract, pancreatic, hepatocellular, and colorectal cancers. We comprehensively describe the current stage-dependent pharmacological management of these malignancies, including chemo-, targeted, and immunotherapy. For each cancer entity, we provide an overview of recent therapeutic advancements and research progress. Finally, we describe how novel insights into tumor heterogeneity and immune evasion deepen our understanding of therapy resistance and provide an outlook on innovative therapeutic strategies that will shape the future management of digestive cancers, including CAR-T cell therapy, novel antibody-drug conjugates and targeted therapies.

Prior work has established hyperthermic intraperitoneal chemotherapy (HIPEC) administration as a safe treatment option for select patients with gastric adenocarcinoma and carcinomatosis. However, identifying patients who will maximally benefit from HIPEC remains unclear. This study assessed a single-institution experience with HIPEC for metastatic gastric cancer to identify variables associated with improved survival.

A database of patients treated for metastatic gastric adenocarcinoma at MD Anderson Cancer Center from 2013 to 2022 was queried for patients undergoing HIPEC as part of their treatment regimen. Patients were stratified by overall survival (OS)≥36 months or <36 months and assessed along demographic and clinicopathologic variables to identify factors associated with OS ≥ 36 months.

Among 104 patients, 1,2, and 3-year OS from diagnosis was 89 %,44 %, and 18 %. Patients with OS ≥ 36 months were more likely to have moderately differentiated tumors, positive cytology only (i.e. no visible carcinomatosis), and lower peritoneal cancer index (PCI) than those with OS < 36 months (p = 0.002, p = 0.01, p = 0.001,respectively). Groups did not otherwise differ with respect to demographic parameters or treatment or pathologic details. Among patients who underwent gastrectomy, those with OS < 36 months had higher pathologic T and N category (p = 0.003 and p = 0.02, respectively). Postoperative mortality was zero in both groups among patients undergoing gastrectomy.

HIPEC may provide more durable survival benefit among patients with metastatic gastric cancer with moderately differentiated disease, low PCI, and positive cytology alone. Additionally, among patients who undergo gastrectomy, higher final pathologic T and N category are associated with worse survival. Trials are needed to compare 3-year OS rates in patients treated with HIPEC versus systemic therapy alone.

Gastric cancer (GC) is a highly heterogeneous disease that varies in both histological presentation and genetic characteristics. Recent advances in the treatment of metastatic and unresectable GC have made several biomarker tests essential for patient management. Predictive biomarkers such as human epidermal growth factor receptor 2 (HER2), programmed death-ligand 1 (PD-L1), mismatch-repair (MMR) proteins, claudin 18.2, and fibroblast growth factor receptor 2b (FGFR2b) are commonly evaluated using immunohistochemistry. However, the expression levels of these biomarkers may vary across different tumor areas, and the accuracy of biomarker diagnosis can be affected by sample quantity, sample location, and collection method. Therefore, tumor heterogeneity presents substantial challenges for accurate biomarker-based diagnosis and prediction of therapeutic responses. Tumor heterogeneity can be categorized into spatial heterogeneity, which refers to variations within the primary tumor (intra-tumoral) or between primary and metastatic sites, and temporal heterogeneity, which encompasses changes over time. This review addresses the tumor heterogeneity in predictive biomarker expression in GC, focusing on HER2, PD-L1, MMR, the Epstein-Barr virus, claudin 18.2, and FGFR2b.

Gastric carcinoma with lymphoid stroma (GCLS) is characterized by dense intra-and peritumoral lymphocytic infiltration and a high rate of Epstein Barr Virus (EBV) infection, suggesting being a promising candidate for immunotherapy. We investigated correlations between PD-L1 expression and clinicopathologic factors, including EBV positivity and microsatellite instability (MSI) status in GCLSs. The study included resected 214 GCLSs and 300 gastric adenocarcinomas (GACs) for control. Epstein Barr Virus encoding region in situ hybridization (EBER ISH), immunohistochemistry for PD-L1 and HER2, dual-colored in situ hybridization for HER2, and MSI analysis were performed. EBV positivity was found in 181 (85%) of 214 GCLSs. MSI analysis demonstrated that 0.6% of EBV + GCLSs and 54.5% of EBV-GCLSs were MSI-high compared to 7% of EBV-GACs. Approximately 3% and 3.9% of HER2 amplifications were found in EBV- and EBV + GCLSs compared to 13% of EBV-GACs. PD-L1 expression with ≥ 1, ≥ 5, and ≥ 10 combined positive scores (CPS) were observed in 81.8%, 70.2%, and 55.3% of EBV + GCLSs. PD-L1 expression with ≥ 10 CPS was observed in 21.2% of EBV-GCLSs, predominantly in MSI-H tumors (85.7%). EBV positivity and MSI are associated with PD-L1 positivity rates in patients with GCLS who may respond better to PD-1/PD-L1 inhibitors but not anti-HER2 inhibitors.

Positron emission tomography (PET) has potential as a complementary technique to biomarker analysis, especially for human epidermal growth factor receptor 2 (HER2)-expressing tumors characterized by high heterogeneity. In this study, zirconium-89 (89Zr) and copper-64 (64Cu) labeled trastuzumab were employed to monitor varying levels of tumoral HER2 expression. Additionally, we studied the use of the cholesterol-depleting lovastatin as a pharmacological approach to enhance cell-surface HER2 expression in tumors with moderate to low HER2 levels, aiming to increase antibody accumulation in these tumor types. Both 89Zr- and 64Cu-labeled trastuzumab effectively monitor HER2 expression levels in xenografts exhibiting varying HER2 expression. No significant difference in tumor uptake was observed between 89Zr- or 64Cu-labeled trastuzumab, and tumor uptake for both radioimmunoconjugates positively correlated with HER2 protein levels. These findings underscore the potential of PET to monitor HER2 protein levels across heterogeneous tumors. Furthermore, our results suggest that further optimization of statin dosing and timing could offer a promising strategy to enhance trastuzumab accumulation in HER2-high, HER2-moderate, and HER2-low tumors.

Background Gallbladder carcinoma (GBC) is a rare but highly aggressive malignancy, often discovered incidentally during cholecystectomy for symptomatic cholelithiasis. Despite significant geographic variation, the association between gallstones and GBC is well-documented, with chronic inflammation from gallstones potentially contributing to carcinogenesis. Objective This study aims to determine the prevalence of incidental GBC in patients undergoing cholecystectomy for symptomatic cholelithiasis at a tertiary care hospital in Peshawar, Pakistan. Materials and methods This retrospective cohort study was conducted at the General Surgery Department, Hayatabad Medical Complex, Peshawar, from February 2, 2021, to July 1, 2024. A total of 230 patients, aged 18-55 years and diagnosed with symptomatic cholelithiasis, were included. Cholecystectomy was performed, and all excised gallbladders were histopathologically examined for carcinoma. Statistical analysis was conducted using IBM SPSS (version 26), with a significance threshold of p ≤ 0.05. Results Out of 230 patients, 7 (3.04%) were found to have incidental GBC upon histopathological examination. Among these, five had adenocarcinoma, and two had papillary carcinoma. The carcinoma was confined to the mucosa (T1a) in four cases, while three cases had deeper invasion (T1b). Patients with incidental carcinoma had a significantly longer symptom duration (mean: 14.2 ± 3.1 months) and were older on average (mean age: 49.2 ± 4.3 years) compared to non-carcinoma patients (p = 0.001 and p = 0.002, respectively). No malignancy was suspected intraoperatively in any case. Conclusion Incidental GBC was present in 3.04% of patients undergoing cholecystectomy for symptomatic cholelithiasis, with longer symptom duration and older age as significant risk factors. The findings underscore the importance of histopathological examination of cholecystectomy specimens in regions with high gallstone prevalence, as early detection of incidental carcinoma can facilitate timely oncological intervention.

Colorectal cancer (CRC) represents a global health threat, standing as the second leading cause of cancer-related death worldwide. Targeted therapies brought new hope for the metastatic stage, which historically bore a very poor prognosis. Human epidermal growth receptor 2 (HER2) overexpression concerns about 5 % of the metastatic CRC (mCRC) patients, including both gene amplifications and point mutations. Albeit its controversial prognostic role, preclinical and clinical data indicate HER2 as a negative predictive biomarker of response to anti-EGFR therapies. Tissue and plasma-based NGS testing, could permit a precise identification of this resistance mechanism both at baseline and during treatment, thus guiding decision-making. Furthermore, promising results come from completed and ongoing randomized trials, testing HER2 as an actionable target. In this review, we discuss the available evidence on HER2 targeting in advanced CRC, analyzing its possible future role in the treatment algorithm.

Claudin-18.2 (CLDN18.2) expression evaluated by immunohistochemistry is a new biomarker for gastric and gastroesophageal junction adenocarcinomas that will soon have market authorization for implementation into routine clinical practice. Despite successful testing in the setting of clinical trials, no specific practical testing guidelines have been proposed. Several preanalytical and analytical variables may interfere with adequate CLDN18.2 staining interpretation; thus, this article provides practical guidance on CLDN18.2 testing and scoring in gastric and gastroesophageal junction adenocarcinomas to identify patients who may respond to targeted therapy with monoclonal antibodies directed against CLDN18.2. Based on available data, moderate to strong (2+/3+) membrane staining in ≥75% of adenocarcinoma cells is the proposed cutoff for clinical use of monoclonal antibody anti-CLDN18.2 (zolbetuximab).

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.

The prognostic significance of T-cell densities in gastric cancer (GC) was previously demonstrated in surgical resection specimens. For prognosis or response prediction, it is preferable to identify biomarkers in pre-treatment biopsies; yet, its representativeness of the tumor immune microenvironment is unclear.

This study aimed to evaluate the concordance and prognostic value of T-cell densities in paired biopsies and resections.

Paired diagnostic biopsies and surgical resections were available for 131 patients with resectable GC who were treated with surgery alone in the D1/D2 trial. T-cell markers such as CD3, CD45RO, CD8, FOXP3, and Granzyme B were assessed by immunohistochemistry and digitally quantified. Tumors were categorized into high and low subgroups for each marker. The concordance between biopsies and resections was determined for each marker with Cohen's κ. To determine the prognostic value of T cells in biopsies, Cox regression was performed.

The concordance of T-cell high and low tumors was moderate for CD8 (κ = 0.58) and weak for other markers (κ < 0.3). CD8 and FOXP3 densities in biopsies were significantly associated with cancer-specific survival. Multivariable analysis showed that an Immunoscore incorporating CD8 and FOXP3 served as an independent prognostic marker (low vs high: hazard ratio 3.40, 95% confidence interval: 1.27-9.10; p = 0.015).

Although the concordance in T-cell densities between biopsy and resection specimens is modest, a biopsy-based Immunoscore identified distinct biological subgroups with prognostic potential. To fully evaluate the prognostic performance of this biopsy Immunoscore, additional studies are warranted.

Therapeutic developments in the targeting of human epidermal growth factor receptor 2 (HER2)-expressing gastric cancer have followed the dramatic success of HER2-expressing breast cancer treatment, which has facilitated the expansion of indications for anti-HER2 agents to include not only conventional HER2-positive breast cancer, but also HER2-low and HER2-ultralow subgroups. The targetability of HER2-low gastric cancer, however, has yet to be established. Hence, further studies are needed to comprehensively understand the clinicopathological features, specific gene alterations, and distinct tumor immune microenvironment of HER2-low gastric cancer and compare them with those for HER2-positive or -negative gastric cancer. Antibody-drug conjugates for HER2 play an important role in making HER2-low gastric cancer targetable. In this context, a deeper understanding of the novel anti-HER2 agents, including antibody-drug conjugates, bispecific T-cell engager antibodies, and a combination of these agents, as well as new forms of immunomodulatory agents are also required. Redefining and re-categorizing HER2 status through not only immunohistochemistry/fluorescence in situ hybridization but also evaluating ERRB2 copy number gain or protein overexpression levels measured using DNA or RNA sequencing might be helpful for identifying populations with HER2-expressing tumors who would ideally benefit from anti-HER2 treatment. The current paper reviewed recent clinical trials, focusing particularly on HER2-low gastric cancer together with basic/translational findings, and discuss perspectives on further therapeutic development in the treatment of this distinct subgroup.

Gastric cancer remains a challenging malignancy with a high global mortality rate. Recent advances in targeted therapy and immunotherapy have shown promise in improving patient outcomes. This paper reviews the impact of incorporating targeted agents such as trastuzumab and immunotherapeutic agents like pembrolizumab into standard chemotherapy regimens for gastric cancer treatment.

A comprehensive analysis was conducted on pivotal clinical trials, including KEYNOTE-590, KEYNOTE-811, and ToGA, focusing on their methodologies, patient populations, treatment regimens, and outcome measures. The review also explored emerging research avenues in precision medicine, particularly genomic sequencing and biomarker identification.

To assess the efficacy and survival benefits of adding trastuzumab and pembrolizumab to standard chemotherapy in the treatment of gastric cancer and to outline future directions in gastric cancer research.

Including trastuzumab and pembrolizumab in treatment regimens for human epidermal growth factor receptor 2 (HER2)-positive and PD-L1-expressing gastric cancers significantly improved progression-free and overall survival rates compared to chemotherapy alone. These findings highlight the potential of personalized therapy in enhancing treatment outcomes. Furthermore, ongoing research into the gastric cancer microenvironment and the role of the microbiome suggests novel targets for future therapeutic interventions.

The integration of targeted and immunotherapeutic agents with traditional chemotherapy represents a pivotal shift in gastric cancer treatment, moving towards more personalized and effective regimens.

A dose-escalation and expansion, phase 1/2 study (ClinicalTrials.gov, NCT04818333) was conducted to assess the novel antibody-drug conjugate SHR-A1811 in pretreated HER2-altered advanced non-small cell lung cancer (NSCLC). Here, we report results from the phase 1 portion. Patients who had previously failed or were intolerant to platinum-based chemotherapy were enrolled and received SHR-A1811 intravenously at doses of 3.2 to 8.0 mg/kg every 3 weeks. Dose escalation followed a Bayesian logistic regression model that included overdose control, with subsequent selection of tolerable levels for dose expansion. Overall, 63 patients were enrolled, including 43 receiving a recommended dose for expansion of 4.8 mg/kg. All patients had HER2-mutant disease. Dose-limiting toxicity occurred in one patient in the 8.0 mg/kg dose cohort. Grade ≥ 3 treatment-related adverse events occurred in 29 (46.0%) patients. One patient in the 6.4 mg/kg cohort died due to interstitial lung disease. As of April 11, 2023, the 4.8 mg/kg cohort showed an objective response rate of 41.9% (95% CI 27.0-57.9), and a disease control rate of 95.3% (95% CI 84.2-99.4). The median duration of response was 13.7 months, with 13 of 18 responses ongoing. The median progression-free survival was 8.4 months (95% CI 7.1-15.0). SHR-A1811 demonstrated favourable safety and clinically meaningful efficacy in pretreated advanced HER2-mutant NSCLC.

This review critically evaluates the evolution and current status of human epidermal growth factor receptor 2 (HER2)-directed therapies in upper gastrointestinal (GI) malignancies, a timely and relevant inquiry given the dynamic shifts in therapeutic strategies over the past decade. Initial enthusiasm following the Trastuzumab for Gastric Cancer (ToGA) study's demonstration of trastuzumab's efficacy, however, encountered hurdles due to subsequent trials showing limited progress, underscoring the necessity for a reevaluation of therapeutic approaches and the exploration of novel agents.

The review highlights significant breakthroughs in the form of immune checkpoint inhibitors and innovative therapeutic technologies, which have redefined treatment paradigms and shown promising efficacy in HER2-positive cases. Emerging treatments such as trastuzumab deruxtecan (T-DXd), zanidatamab and evorpacept further illustrate the ongoing efforts to leverage unique mechanisms of action for improved HER2-positive antitumor activity.

The advancements in HER2-directed therapies underscore a pivotal era in the management of upper GI malignancies. These developments not only reflect the profound impact of integrating novel therapeutic combinations but also highlight the critical role of ongoing research in overcoming resistance mechanisms and tailoring treatment to individual disease profiles.

With one of the highest mortality rates of all malignancies, the 5-year survival rate for esophageal cancer is under 20%. Depending on the stage and extent of the disease, the current standard of care treatment paradigm includes chemotherapy or chemoradiotherapy followed by surgical esophagogastrectomy, with consideration for adjuvant immunotherapy for residual disease. This regimen has high morbidity, due to anatomic changes inherent in surgery, the acuity of surgical complications, and off-target effects of systemic chemotherapy and immunotherapy. We begin with a review of current treatments, then discuss new and emerging targets for therapies and advanced drug delivery systems. Recent and ongoing preclinical and early clinical studies are evaluating traditional tumor targets (e.g., human epidermal growth factor receptor 2), as well as promising new targets such as Yes-associated protein 1 or mammalian target of rapamycin to develop new treatments for this disease. Due the function and location of the esophagus, opportunities also exist to pair these treatments with a drug delivery strategy to increase tumor targeting, bioavailability, and intratumor concentrations, with the two most common delivery platforms being stents and nanoparticles. Finally, early results with antibody drug conjugates and chimeric antigenic receptor T cells show promise as upcoming therapies. This review discusses these innovations in therapeutics and drug delivery in the context of their successes and failures, with the goal of identifying those solutions that demonstrate the most promise to shift the paradigm in treating this deadly disease.

The significant clinical benefits of human epidermal growth factor receptor 2 (HER2)-targeted therapeutic agents have revolutionized the clinical treatment landscape in a variety of human solid tumours. Accordingly, accurate evaluation of HER2 status in these different tumour types is critical for clinical decision making to select appropriate patients who may benefit from life-saving HER2-targeted therapies. HER2 biomarker scoring criteria is different in different organ systems, and close adherence to the corresponding HER2 biomarker testing guidelines and their updates, if available, is essential for accurate evaluation. In addition, knowing the unusual patterns of HER2 expression is also important to avoid inaccurate evaluation. In this review, we discuss the key considerations when evaluating HER2 status in solid tumours for clinical decision making, including tissue handling and preparation for HER2 biomarker testing, as well as pathologist's readout of HER2 testing results in breast carcinomas, gastroesophageal adenocarcinomas, colorectal adenocarcinomas, gynaecologic carcinomas, and non-small cell lung carcinomas.

The influence of Helicobacter-pylori (H. pylori) infection and the characteristics of gastric cancer (GC) on tumor-infiltrating lymphocyte (TIL) levels has not been extensively studied. Analysis of infiltrating-immune-cell subtypes as well as survival is necessary to obtain comprehensive information.

To determine the rates of deficient mismatch-repair (dMMR), HER2-status and H. pylori infection and their association with TIL levels in GC.

Samples from 503 resected GC tumors were included and TIL levels were evaluated following the international-TILs-working-group recommendations with assessment of the intratumoral (IT), stromal (ST) and invasive-border (IB) compartments. The density of CD3, CD8 and CD163 immune cells, and dMMR and HER2-status were determined by immunohistochemistry (IHC). H. pylori infection was evaluated by routine histology and quantitative PCR (qPCR) in a subset of samples.

dMMR was found in 34.4%, HER2+ in 5% and H. pylori-positive in 55.7% of samples. High IT-TIL was associated with grade-3 (P = 0.038), while ST-TIL with grade-1 (P < 0.001), intestinal-histology (P < 0.001) and no-recurrence (P = 0.003). dMMR was associated with high TIL levels in the ST (P = 0.019) and IB (P = 0.01) compartments, and ST-CD3 (P = 0.049) and ST-CD8 (P = 0.05) densities. HER2- was associated with high IT-CD8 (P = 0.009). H. pylori-negative was associated with high IT-TIL levels (P = 0.009) when assessed by routine-histology, and with high TIL levels in the 3 compartments (P = 0.002-0.047) and CD8 density in the IT and ST compartments (P = 0.001) when assessed by qPCR. A longer overall survival was associated with low IT-CD163 (P = 0.003) and CD8/CD3 (P = 0.001 in IT and P = 0.002 in ST) and high IT-CD3 (P = 0.021), ST-CD3 (P = 0.003) and CD3/CD163 (P = 0.002).

TIL levels were related to dMMR and H. pylori-negativity. Low CD8/CD3 and high CD163/CD3 were associated with lower recurrence and longer survival.

Gastric cancer and gastroesophageal junction cancer represent the leading cause of tumor-related death worldwide. Although advances in immunotherapy and molecular targeted therapy have expanded treatment options, they have not significantly altered the prognosis for patients with unresectable or metastatic gastric cancer. A minority of patients, particularly those with PD-L1-positive, HER-2-positive, or MSI-high tumors, may benefit more from immune checkpoint inhibitors and/or HER-2-directed therapies in advanced stages. However, for those lacking specific targets and unique molecular features, conventional chemotherapy remains the only recommended effective and durable regimen. In this review, we summarize the roles of various signaling pathways and further investigate the available targets. Then, the current results of phase II/III clinical trials in advanced gastric cancer, along with the superiorities and limitations of the existing biomarkers, are specifically discussed. Finally, we will offer our insights in precision treatment pattern when encountering the substantial challenges.

In tumor treatment, the deposition of nanoenzymes in normal tissues and cause potential side effects are unavoidable. Here, we designed an intelligent biomimetic nanoenzymes carrier platform (MSCintelligent) that endows the carrier platform with "wisdom" by introducing Affibody-Notch(core)-VP64-GAL4/UAS-HSV-TK artificial signal pathways to mesenchymal stem cells (MSCs). This intelligent nanoenzymes carrier platform is distinguished from the traditional targeting tumor microenvironment or enhancing affinity with tumor, which endue MSCintelligent with tumor signal recognition capacity, so that MSCintelligent can autonomously distinguish tumor from normal tissue cells and feedback edited instructions. In this study, MSCintelligent can convert tumor signals into HSV-TK instructions through artificial signal pathway after recognizing Her2 (+) tumor. Subsequently, the synthesized HSV-TK can rupture MSCintelligent under the mediation of ganciclovir, and release the preloaded Cu/Fe nanocrystal clusters to kill the tumor accurately. Meanwhile, MSCintelligent without recognizing tumors will not initiate the HSV-TK instructions, thus being unresponsive to GCV and blocking the release of nanoenzymes in normal tissues. Consequently, MSCintelligent is the first intelligent biomimetic nanoenzymes carrier platform, which represents a new biomimetic nanoenzymes targeting mode.

Gastric cancers frequently harbor striking histological complexity and diversity between lesions as well as within single lesions, known as inter- and intratumoral heterogeneity, respectively. The latest World Health Organization Classification of Tumors designated more than 30 histological subtypes for gastric epithelial tumors, assigning 12 subtypes for gastric adenocarcinoma (GAD). Meanwhile, recent advances in genome-wide analyses have provided molecular aspects to the histological classification of GAD, and consequently revealed different molecular traits underlying these histological subtypes. Moreover, accumulating knowledge of comprehensive molecular profiles has led to establishing molecular classifications of GAD, which are often associated with clinical biomarkers for therapeutics and prognosis. However, most of our knowledge of GAD molecular profiles is based on inter-tumoral heterogeneity, and the molecular profiles underlying intratumoral heterogeneity are yet to be determined. In this review, recently established molecular classifications of GAD are introduced in the aspect of pathological diagnosis and are discussed in the context of intratumoral heterogeneity.

The Trastuzumab for Gastric Cancer (ToGA) trial marked a pivotal moment in the adoption of trastuzumab for treating advanced human epidermal growth factor receptor 2 (HER2)-positive esophagogastric (EG) cancer. The KEYNOTE-811 trial brought to light the synergistic effect of immune modulation and HER2 targeting. Additionally, the emergence of trastuzumab deruxtecan (T-DXd) highlighted the potential of new pharmaceutical technologies to extend response, particularly for patients who have advanced beyond initial HER2-targeted therapies. This review aims to navigate through both the successes and challenges encountered historically, as well as promising current trials on innovative and transformative therapeutic strategies, including promising first-in-class and novel first-in-human agents.

Epitope binning, an approach for grouping antibodies based on epitope similarities, is a critical step in antibody drug discovery. However, conventional methods are complex, involving individual antibody production. Here, we established Epitope Binning-seq, an epitope binning platform for simultaneously analyzing multiple antibodies. In this system, epitope similarity between the query antibodies (qAbs) displayed on antigen-expressing cells and a fluorescently labeled reference antibody (rAb) targeting a desired epitope is analyzed by flow cytometry. The qAbs with epitope similar to the rAb can be identified by next-generation sequencing analysis of fluorescence-negative cells. Sensitivity and reliability of this system are confirmed using rAbs, pertuzumab and trastuzumab, which target human epidermal growth factor receptor 2. Epitope Binning-seq enables simultaneous epitope evaluation of 14 qAbs at various abundances in libraries, grouping them into respective epitope bins. This versatile platform is applicable to diverse antibodies and antigens, potentially expediting the identification of clinically useful antibodies.

HER2 amplification-associated molecular alterations and clinicopathologic features in colorectal cancers (CRCs) have not been well established. In this study, we assessed the prevalence of HER2 amplification and microsatellite instability (MSI) status of 992 patients with primary CRC. In addition, molecular alterations of HER2 amplified and unamplified CRCs were examined and compared by next-generation sequencing. HER2 amplifications were found in 41 (4.1%) of 992 primary CRCs. HER2 amplification was identified in 1.0% of the right colonic tumors, 5.1% of the left colonic tumors, and 4.8% of the rectal tumors. Approximately 95% of HER2 amplification was observed in the left colon and rectum. Seven (87.5%) of eight metastatic tumors showed HER2 amplification. Most clinicopathologic features were unrelated to HER2 amplification except tumor size and MSI status. All 41 HER2 amplified CRCs were microsatellite stable. In a molecular analysis of frequently identified somatic mutations in CRCs, HER2 amplified CRCs showed a lower rate of KRAS mutations (24.4%) but a higher rate of TP53 mutations (83%) than unamplified CRCs. No BRAF and NRAS mutations were identified in HER2 amplified CRCs. Our study suggests that HER2 amplified CRCs are mutually exclusive of MSI and harbor less frequent KRAS/NRAS/BRAF mutations but frequent T53 mutations.

Colorectal cancer (CRC) is one of the most common causes of tumor-related deaths globally. Despite recent improvements in the comprehensive therapy of malignancy, metastatic CRC continues to have a poor prognosis. Human epidermal growth factor receptor 2 (HER2) is an established oncogenic driver, which is successfully targeted for breast and gastric cancers. Approximately 5% of CRC patients carry somatic HER2 mutations or gene amplification. In 2019, the U.S. Food and Drug Administration have approved trastuzumab and pertuzumab in combination with chemotherapy for the treatment of HER2-positive metastatic CRC. This approval marked a significant milestone in the treatment of CRC, as HER2-positive patients now have access to targeted therapies that can improve their outcomes. Yet, assessment for HER2 overexpression/ amplification in CRC has not been standardized. The resistance mechanisms to anti-HER2 therapy have been not clearly investigated in CRC. Although many unknowns remain, an improved understanding of these anti-HER2 agents will be essential for advanced CRC. In this review, we provide an overview of the role of HER2 in CRC as an oncogenic driver, a prognostic and predictive biomarker, and a clinically actionable target, as well as the current progress and challenges in the field.

Evaluation of PD-L1 tumor proportion score (TPS) by pathologists has been very impactful but is limited by factors such as intraobserver/interobserver bias and intratumor heterogeneity. We developed an artificial intelligence (AI)-powered analyzer to assess TPS for the prediction of immune checkpoint inhibitor (ICI) response in advanced non-small cell lung cancer (NSCLC).

The AI analyzer was trained with 393,565 tumor cells annotated by board-certified pathologists for PD-L1 expression in 802 whole-slide images (WSIs) stained by 22C3 pharmDx immunohistochemistry. The clinical performance of the analyzer was validated in an external cohort of 430 WSIs from patients with NSCLC. Three pathologists performed annotations of this external cohort, and their consensus TPS was compared with AI-based TPS.

In comparing PD-L1 TPS assessed by AI analyzer and by pathologists, a significant positive correlation was observed (Spearman coefficient = 0.925; P < .001). The concordance of TPS between AI analyzer and pathologists according to TPS ≥50%, 1%-49%, and <1% was 85.7%, 89.3%, and 52.4%, respectively. In median progression-free survival (PFS), AI-based TPS predicted prognosis in the TPS 1%-49% or TPS <1% group better than the pathologist's reading, with the TPS ≥50% group as a reference (hazard ratio [HR], 1.49 [95% CI, 1.19 to 1.86] v HR, 1.36 [95% CI, 1.08 to 1.71] for TPS 1%-49% group, and HR, 2.38 [95% CI, 1.69 to 3.35] v HR, 1.62 [95% CI, 1.23 to 2.13] for TPS <1% group).

PD-L1 TPS assessed by AI analyzer correlates with that of pathologists, with clinical performance also being comparable when referenced to PFS. The AI model can accurately predict tumor response and PFS of ICI in advanced NSCLC via assessment of PD-L1 TPS.

Gastric cancer has a high incidence and fatality rate, and surgery is the preferred course of treatment. Nonetheless, patient survival rates are still low, and the incidence of major postoperative complications cannot be disregarded. The systemic inflammatory response, nutritional level, and coagulation status are key factors affecting the postoperative recovery and prognosis of gastric cancer patients. The systemic inflammatory response index (SIRI) and the albumin fibrinogen ratio (AFR) are two valuable comprehensive indicators of the severity and prognosis of systemic inflammation in various medical conditions.

To assess the clinical importance and prognostic significance of the SIRI scores and the AFR on early postoperative outcomes in patients undergoing radical gastric cancer surgery.

We conducted a retrospective analysis of the clinicopathological characteristics and relevant laboratory indices of 568 gastric cancer patients from January 2018 to December 2019. We calculated and compared two indicators of inflammation and then examined the diagnostic ability of combined SIRI and AFR values for serious early postoperative complications. We scored the patients and categorized them into three groups based on their SIRI and AFR levels. COX analysis was used to compare the three groups of patients the prognostic value of various preoperative SIRI-AFR scores for 5-year overall survival (OS) and disease-free survival (DFS).

SIRI-AFR scores were an independent risk factor for prognosis [OS: P = 0.004; hazards ratio (HR) = 3.134; DFS: P < 0.001; HR = 3.543] and had the highest diagnostic power (area under the curve: 0.779; 95% confidence interval: 0.737-0.820) for early serious complications in patients with gastric cancer. The tumor-node-metastasis stage (P = 0.001), perioperative transfusion (P = 0.044), positive carcinoembryonic antigen (P = 0.014) findings, and major postoperative complications (P = 0.011) were factors associated with prognosis.

Preoperative SIRI and AFR values were significantly associated with early postoperative survival and the occurrence of severe complications in gastric cancer patients.

Primary mucinous ovarian carcinoma (MOC) is a rare ovarian epithelial cancer, which is often refractory to chemotherapy. HER2-targeting therapy is being increasingly considered in gynecologic malignancies. Although there have been limited studies examining the HER2 status of such tumors, the criteria for HER2 expression scoring have not been standardized for MOC as it has for other sites. This study aimed to survey immunohistochemical HER2 expression patterns in MOC and its precursor, mucinous borderline tumor in correlation with fluorescence in situ hybridization (FISH). Immunohistochemistry (IHC) for HER2 was performed on 12 cases of MOC and 15 mucinous borderline tumors, including 7 with intraepithelial carcinoma. HER2 expression was quantified using the gastric/gastroesophageal carcinoma protocol. Cases were considered 3+ if the tumor cells displayed strong complete or basolateral/lateral membranous staining in ≥10% of tumor cells. Cases (2+) had weak to moderate staining in ≥10% of tumor cells. Cases (1+) had faint staining in ≥10% of tumor cells. Cases considered 0 had no staining or faint staining in <10% of tumor cells. HER2 expression was also quantified with the endometrial serous carcinoma protocol, which uses a 30% tumor cell positivity cutoff. FISH for HER2 was performed on all 3+ and 2+ and a subset of 1+ cases. Of the MOC cases, 25% were 3+ and 1 mucinous borderline tumor with intraepithelial carcinoma had 3+ staining. All 3+ IHC MOC cases had >30% basolateral membranous staining. HER2 amplification was confirmed by FISH on all 3+ IHC cases and in one 2+ IHC case of MOC. Up to 25% of mucinous ovarian tumors showed HER2 IHC overexpression with an excellent correlation between IHC and FISH using the HER2 scoring protocol for either gastric/gastroesophageal carcinoma or uterine serous carcinoma.

Gastric cancer (GC) is a heterogeneous disease, often diagnosed at advanced stages, with a 5-year survival rate of approximately 20%. Despite notable technological advancements in cancer research over the past decades, their impact on GC management and outcomes has been limited. Numerous molecular alterations have been identified in GC, leading to various molecular classifications, such as those developed by The Cancer Genome Atlas (TCGA) and the Asian Cancer Research Group (ACRG). Other authors have proposed alternative perspectives, including immune, proteomic, or epigenetic-based classifications. However, molecular stratification has not yet transitioned into clinical practice for GC, and little attention has been paid to alternative molecular classifications. In this review, we explore diverse molecular classifications in GC from a practical point of view, emphasizing their relationships with clinicopathological factors, prognosis, and therapeutic approaches. We have focused on classifications beyond those of TCGA and the ACRG, which have been less extensively reviewed previously. Additionally, we discuss the challenges that must be overcome to ensure their impact on patient treatment and prognosis. This review aims to serve as a practical framework to understand the molecular landscape of GC, facilitate the development of consensus molecular categories, and guide the design of innovative molecular studies in the field.

About 20% of breast and gastric cancers and 3% of colorectal carcinomas overexpress the human epidermal growth factor receptor 2 (HER2) and are sensitive to HER2-directed agents. The expression of HER2 may differ within the same tumoral lesion (spatial intralesional heterogeneity), from different tumor locations (spatial interlesional heterogeneity), and throughout treatments (temporal heterogeneity). Spatial and temporal heterogeneity may impact on response and resistance to HER2-targeting agents and its prevalence and predictive role changes across HER2-overexpressing solid tumors. Therefore, the definition and the characterization of HER2 heterogeneity pose many challenges and its implementation as a reproducible predictive biomarker would help in guiding treatment modulation.