Specific Tumor Types Research Articles

A comprehensive target panel allows to extend the genetic spectrum of neuroendocrine tumors.

Neuroendocrine tumors (NETs) frequently have a genetic basis, and the range of genes implicated in NETs development continues to expand. Application of targeted gene panels (TGP) in next-generation sequencing (NGS) is a central strategy for elucidating novel variants associated with NETs development. In this study, we conducted comprehensive molecular-genetic analyses using TGP on a cohort of 93 patients diagnosed with various NETs subtypes, mainly accompanied by various endocrine syndromes: insulinoma (n=26), pheochromocytoma and paraganglioma (PPGL) (n=38), parathyroid adenoma (n=18, including three with insulinoma), and NETs of other locations (n=14). The TGP encompassed genes linked to diverse NETs and other hereditary endocrine disorders, with subsequent variant classification according to the American College of Medical Genetics and Genomics guidelines. Among the identified variants, 20 were found in genes previously linked to specific tumor types, and 10 were found in genes with a limited likelihood and unclear molecular mechanisms of association with observed NETs. Remarkably, 13 variants were discovered in genes not previously associated with the NETs observed in our patients. These genes, such as ABCC8, KCNJ11, KLF11, HABP2, and APC, were implicated in insulinoma; ZNRF3, GNAS, and KCNJ5 were linked with PPGL; parathyroid adenomas were related to variants in SDHB and TP53; while NETs of other locations displayed variants in APC and ABCC8. Our study demonstrates that utilizing broad TGP in examining patients with various functioning NETs, facilitates the identification of new germinal variants in genes that may contribute to the diseases. The verification of revealed findings requires research in vaster sample.

An Introduction to Tertiary Lymphoid Structures in Cancer.

Immunotherapy has revolutionized therapeutics for cancer patients, which signifies the importance of effective antitumor immunity in combatting cancer. However, the benefit of immunotherapies is limited to specific patient populations and tumor types, suggesting the overt need for new immunotherapeutic targets. Tertiary lymphoid structures (TLS) are ectopic lymph node-like structures that develop at the sites of chronic inflammation such as cancer. TLS are correlated with favorable clinical outcomes across multiple solid tumors and are associated with increased tumor-infiltrating lymphocytes (TILs), particularly effector memory CD8+ T cells. Despite strong clinical data in humans, there are still major knowledge gaps on the function of TLS in cancer. Herein, we highlight the known biology and clinical impact of TLS, which offer further evidence to harness TLS for improved immunotherapeutics.

BIOM-61. CSF CTDNA ANALYSIS OF PATIENTS WITH DIFFUSE GLIOMAS REVEALS DIAGNOSTIC MOLECULAR ALTERATIONS

Abstract There is a critical need for better strategies to diagnose and monitor patients with diffuse gliomas. Liquid biopsies are less invasive than tissue biopsies and are amenable to serial collection at multiple timepoints. However, analysis of circulating tumor DNA (ctDNA) in cerebrospinal fluid (CSF) in patients with diffuse gliomas remains underutilized in clinical practice due to technical challenges and a scarcity of studies demonstrating clinical utility. We evaluated ctDNA in 49 CSF samples from patients with various types of diffuse gliomas with a next generation sequencing (NGS) panel interrogating 613 cancer-related genes. Cell-free DNA concentration obtained from CSF (0.4-5mL) ranged from 0.009 to 60ng/µL. Input DNA concentration ranged from 0.12-30ng. Mutations were detected in 29/49 (59.2%) samples including 22/49 (44.9%) with single nucleotide changes, 14/49 (28.6%) with copy number changes, and 1 fusion (2.0%). The majority of samples without mutations detected (n=20) had suboptimal DNA input (<30ng): 17/20 (85%). We identified diagnostic alterations in CSF including mutations in IDH1 (3/5 IDH-mutant gliomas), TERTp and EGFR amplification (7/34 glioblastomas), H3-3A (4/6 pediatric high-grade gliomas). Some of these mutations, in combination with other clinical parameters, allowed us to identify specific CNS tumor types based on the 2021 WHO classification of CNS tumors, resulting in the reclassification of 2 patients. Matched tumor tissue sequencing results were available for 23/49 (46.9%) patients and the results showed good concordance with CSF ctDNA analysis. In summary, our results suggest that the NGS analysis of CSF-ctDNA can provide clinically relevant information in patients with diffuse gliomas.

IMMU-07. THE IMMUNE LANDSCAPE OF PEDIATRIC BRAIN TUMORS: A TRANSCRIPTOMIC ANALYSIS

Abstract Despite standard-of-care therapy, pediatric brain tumors are now the leading cause of cancer-related death in children, highlighting an urgent need for the development of new treatments. Immunotherapy is actively being evaluated as a therapeutic approach to pediatric brain tumors, however, more research is needed to reveal additional antigenic targets that exist in these malignancies. In this study, our team performed a transcriptomic analysis of pediatric brain tumor RNA sequencing data within the Children’s Brain Tumor Network (CBTN) to identify intra and extracellular antigens that are highly expressed across major tumor types. Interestingly, our team observed that most tumors had high gene expression of a group of antigens that were unique to that specific tumor type. Specifically, our analysis revealed that diffuse midline gliomas (DMGs) highly expressed the extracellular antigens CA9, CTCFL, and ST8SIA1, whereas atypical rhabdoid tumors (ATRTs) highly expressed MUC1 and TEK. Other tumors that displayed high gene expression for a variety of antigenic targets included H3-wildtype high-grade gliomas (HGGs), and ependymomas (EPNs). Strikingly, we observed minimal difference in antigen expression in primary tumors when compared to patient-matched recurrences. Beyond antigen expression, we evaluated the expression of antigen processing machinery (APM) which includes major histocompatibility complexes (MHCs). Our findings revealed that DMGs had the lowest level of APM expression, however, these tumors uniquely expressed high levels of the immune checkpoints ADORA2A, CD276, and KLRC1. Contrarily, ATRTs showed a high expression of immune checkpoints CD274 (PD-L1), PVR, and CD80. Other tumors included in our analysis had unique expression patterns of antigen, as well as APM and immune checkpoints. Our findings illustrate that pediatric brain tumors have distinct expression patterns of antigens, APM, and immune checkpoints that are specific to tumor type, emphasizing diverse, rather than general, immunotherapeutic approaches must be considered for childhood brain tumors.

Surgery With or Without Radiotherapy Versus Radiotherapy Alone for Malignant Spinal Cord Compression: An Updated Meta-analysis.

A systematic review and meta-analysis. To conduct a meta-analysis of studies that compared surgery with or without radiotherapy to radiotherapy alone for patients with malignant spinal cord compression, and a subgroup analysis of patients stratified by hematologic and solid malignancies. Two previous meta-analyses showed that surgery with or without radiotherapy was better than radiotherapy alone in patients with malignant spinal cord compression. Nevertheless, there was no stratification by tumor type, leading to uncertainty regarding best approach for patients with hematologic malignancies. We searched PubMed, Scopus, and Web of Science, for studies comparing surgery with or without radiotherapy to radiotherapy alone in patients with malignant spinal cord compression. The primary outcomes were improvement in ambulatory status and survival at 12 months. For neurological outcomes, we included studies involving both locally advanced primary malignancies of the spine and metastatic tumors. We restricted our analysis to studies on metastases for survival outcomes. We included 2536 patients from 18 studies. Surgery was performed in 890 (35%) patients. The pooled analysis of all studies revealed that improvement in ambulatory status (OR 2.65; 95% CI 1.60-4.39) and survival at 12 months (OR 1.66; 95% CI 1.10-2.52) were significantly higher in patients who underwent surgery with or without radiotherapy. Improvement in ambulatory status (OR 1.92; 95% CI 1.19-3.09) and survival at 12 months (OR 4.24; 95% CI 2.35-7.66) were significantly higher in patients with hematologic malignancies in the surgical arm. The primary outcomes were not significantly different between patients with solid malignancies. Surgical intervention demonstrates superior neurological outcomes and increased survival compared with radiotherapy alone. Subgroup analysis revealed that patients with hematologic malignancies on surgery group experienced superior primary outcomes; however, high risk of bias of the included studies preclude definitive changes in standard care based on this data. These findings underscore the need for further research regarding the efficacy of surgical versus radiotherapeutic approaches for specific tumor types. 2.

Three-Dimensional Model Analysis Revealed Differential Cytotoxic Effects of the NK-92 Cell Line and Primary NK Cells on Breast and Ovarian Carcinoma Cell Lines Mediated by Variations in Receptor-Ligand Interactions and Soluble Factor Profiles.

Background/objectives: The functional activity of a certain tumor determines the effectiveness of primary NK cells and NK-92 cell line-based cancer therapy; their therapeutic effectiveness against different tumors can vary. This work provides a direct simultaneous comparison of the cytotoxic effects of in vitro-activated peripheral NK (pNK) cells and NK-92 cells in spheroid models of BT-474, MCF7 and SKOV-3 carcinomas and uncovers the reasons for the differential effectiveness of NK cells against tumors. Methods: Tumor spheroids of similar size and shape, obtained from agarose molds, were incubated with NK-92 or pNK cells for 24 h. Tumor cell death was detected using flow cytometry or confocal microscopy. Cytokine production, granzyme B levels and NK cell degranulation analyses were performed, along with pNK and target-cell phenotypic characterization. Results: While NK-92 and pNK cells lysed BT-474 spheroids with comparably low efficiency, pNK cells were more capable of eliminating MCF7 and SKOV-3 spheroids than NK-92 cells were. The results of the functional and phenotypic analyses strongly support the participation of the NKG2D-NKG2DL pathway in pNK cell activation induced by the most sensitive cytotoxic attack on SKOV-3 spheroids, whereas the CX3CR1-CX3CL1 axis appears to be involved in the pNK reaction against MCF-7 spheroids. Conclusions: We provide a new approach for the preliminary identification of the most promising NK cell receptors that can alter the effectiveness of cancer therapy depending on the specific tumor type. Using this approach, NK-92 cells or pNK subsets can be selected for further accumulation and/or genetic modification to improve specificity and reactivity.

Formononetin suppresses the malignant progression of papillary thyroid carcinoma depending on downregulation of CBX4.

Papillary thyroid carcinoma (PTC) is the most common malignant tumor of the endocrine system globally. Formononetin (FMNT), an isoflavonoid, exerts anti-tumorigenic effects and chromobox homolog 4 (CBX4) exerts tumor-promoting effect in specific types of tumors. Nevertheless, the predictive values and biological functions of FMNT and CBX4 in the pathological progress of PTC have not been fully understood till now. In the present study, the human PTC cell line TPC-1 was exposed to 0, 10, 30 and 100 µM FMNT for 24 h to elucidate the precise effects of FMNT on the biological behaviors of PTC cells. Moreover, FMNT-treated TPC-1 cells were transfected with oe-CBX4 to evaluate whether CBX4 was implicated in the anticarcinogenic effects of FMNT against PTC. It was demonstrated that FMNT treatment suppressed the proliferation, clone formation, migration, invasion, EMT, angiogenesis and stemness of PTC cells in a dose-dependent manner. Furthermore, it was verified that FMNT targeted CBX4 to downregulate its expression in a dose dependent manner. The suppressive effects of FMNT on the proliferation, clone formation, migration, invasion, EMT, angiogenesis and stemness of PTC cells were partially reversed by CBX4 overexpression. Upregulation of CBX4 abolished the tumor suppression effects of FMNT in the malignant progression of PTC. In conclusion, FMNT might act as a promising anti-tumorigenic agent in PTC, which depends on the downregulation of CBX4.

Surgical Treatment and Clinical Evaluation of Calvarial Metastases.

The aim of this study is to explore surgical treatment techniques and clinical attributes associated with calvarial metastases, while providing a comprehensive review of the treatment experiences relevant to this particular type of tumor. This study involves a retrospective analysis of clinical data from 12 patients diagnosed with calvarial metastatic tumors who underwent surgical intervention. Among these patients, 5 had a history of previous malignant tumor resections, while 7 presented with calvarial metastatic tumors as their initial symptom. In all cases, the surgical approach consisted of calvarial tumor resection followed by titanium mesh repair. Following the surgical intervention, all patients underwent a comprehensive course of treatment, encompassing both local radiotherapy and systemic chemotherapy. In 1 instance, a patient presented with multiple tumors located in the central area of the frontal bone and the right temporal bone. The larger tumor situated in the middle of the frontal bone was surgically excised, while the tumor in the right temporal bone was treated using radiotherapy. In 2 cases characterized by multiple metastases within the skull, a comprehensive excision of all tumors was accomplished in a single surgical procedure. In the remaining cases featuring a solitary metastatic growth, the respective tumors were surgically removed. There were 10 instances of dura mater invasion and 3 cases involving the invasion of brain tissue. Pathologic examinations revealed 1 case of metastatic lung adenocarcinoma, 1 case of metastatic paraganglioma, 1 case of metastatic hepatocellular carcinoma, 2 cases of metastatic thyroid carcinoma, and 7 cases of metastatic clear cell renal cell carcinoma. Throughout the follow-up period, spanning from 14 to 90 months, various outcomes were noted. These included three occurrences of in situ recurrence. In addition, 1 patient required 3 distinct surgical interventions, while 2 other patients underwent 2 separate surgical procedures each. Notably, 1 of these cases involved the exposure of the titanium mesh on the scalp, necessitating the removal of the titanium mesh. Regrettably, there have been 9 recorded fatalities among the patients, while 3 individuals have survived. Solitary metastasis of calvarium region is rare, and surgical resection is effective. However, it is necessary to extend the resection range and combine with local radiotherapy to avoid local recurrence. Surgical intervention can significantly enhance the quality of life for affected patients. The prognosis of the patients mainly depends on the treatment of the primary disease and the situation of important organ dissemination and treatment.

Health Disparities among Patients with Cancer Who Received Molecular Testing for Biomarker-Directed Therapy.

Health disparities present a barrier to successful oncology treatment. The potential for precision oncology to reduce health disparities has not previously been analyzed. We performed a retrospective analysis of 12,627 patients from six major cancer centers whose tumors underwent molecular testing at Caris Life Sciences between 2010 and 2020. Kaplan-Meier and Cox regression were used to describe and analyze overall survival. The molecular and demographic features of the cohort were analyzed by χ2 and ANOVA tests. Black patients composed 25% of the cohort and White patients 63%. Among this molecularly-tested cohort, there were minimal outcome differences based on race, geographic location, or poverty level. When analyzing the interaction of age, race, and sex, racial-based disparities were noted primarily for young non-White women in the study cohort but were more pronounced for men and women of all ages in the broader patient population within the Surveillance, Epidemiology, and End Results database. Mutations in five genes-APC, EGFR, STK11, TP53, and KRAS-were found to affect overall survival among our cohort, and their prevalence varied by race in specific tumor types. Real-world outcomes data in mutation-defined cohorts also provided additional context to previously reported therapeutic response trends. Our study shows that patients who undergo molecular testing display reduced racial health disparities compared with the general population, whereas persistent racial disparities are influenced by age and sex. Genomic-driven racial disparities should be examined at a tumor lineage-specific level. Increased access to molecular testing for all eligible patients may play a role in improving health equity. Significance: This study is the largest of its kind to analyze health disparities and genomic features among a diverse multiinstitutional cohort of patients who underwent molecular testing. Continuing to increase awareness of and access to molecular testing approaches may help to reduce cancer health disparities and improve outcomes for all patients.

Expert-Guided Large Language Models for Clinical Decision Support in Precision Oncology.

Rapidly expanding medical literature challenges oncologists seeking targeted cancer therapies. General-purpose large language models (LLMs) lack domain-specific knowledge, limiting their clinical utility. This study introduces the LLM system Medical Evidence Retrieval and Data Integration for Tailored Healthcare (MEREDITH), designed to support treatment recommendations in precision oncology. Built on Google's Gemini Pro LLM, MEREDITH uses retrieval-augmented generation and chain of thought. We evaluated MEREDITH on 10 publicly available fictional oncology cases with iterative feedback from a molecular tumor board (MTB) at a major German cancer center. Initially limited to PubMed-indexed literature (draft system), MEREDITH was enhanced to incorporate clinical studies on drug response within the specific tumor type, trial databases, drug approval status, and oncologic guidelines. The MTB provided a benchmark with manually curated treatment recommendations and assessed the clinical relevance of LLM-generated options (qualitative assessment). We measured semantic cosine similarity between LLM suggestions and clinician responses (quantitative assessment). MEREDITH identified a broader range of treatment options (median 4) compared with MTB experts (median 2). These options included therapies on the basis of preclinical data and combination treatments, expanding the treatment possibilities for consideration by the MTB. This broader approach was achieved by incorporating a curated medical data set that contextualized molecular targetability. Mirroring the approach MTB experts use to evaluate MTB cases improved the LLM's ability to generate relevant suggestions. This is supported by high concordance between LLM suggestions and expert recommendations (94.7% for the enhanced system) and a significant increase in semantic similarity from the draft to the enhanced system (from 0.71 to 0.76, P = .01). Expert feedback and domain-specific data augment LLM performance. Future research should investigate responsible LLM integration into real-world clinical workflows.

Combination screen in multi-cell type tumor spheroids reveals interaction between aryl hydrocarbon receptor antagonists and E1 ubiquitin-activating enzyme inhibitor

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that regulates genes of drug transporters and metabolic enzymes to detoxify small molecule xenobiotics. It has a complex role in cancer biology, influencing both the progression and suppression of tumors by modulating malignant properties of tumor cells and anti-tumor immunity, depending on the specific tumor type and developmental stage. This has led to the discovery and development of selective AhR modulators, including BAY 2416964 which is currently in clinical trials. To identify small molecule anticancer agents that might be combined with AhR antagonists for cancer therapy, a high-throughput combination screen was performed using multi-cell type tumor spheroids grown from malignant cells, endothelial cells, and mesenchymal stem cells. The AhR selective antagonists BAY 2416964, GNF351, and CH-223191 were tested individually and in combination with twenty-five small molecule anticancer agents. As single agents, BAY 2416964 and CH-223191 showed minimal activity, whereas GNF351 reduced the viability of some spheroid models at concentrations greater than 1 µM. The activity of most combinations aligned well with the single agent activity of the combined agent, without apparent contributions from the AhR antagonist. All three AhR antagonists sensitized tumor spheroids to TAK-243, an E1 ubiquitin-activating enzyme inhibitor. These combinations were active in spheroids containing bladder, breast, ovary, kidney, pancreas, colon, and lung tumor cell lines. The AhR antagonists also potentiated pevonedistat, a selective inhibitor of the NEDD8-activating enzyme E1 regulatory subunit, in several tumor spheroid models. In contrast, the AhR antagonists did not enhance the cytotoxicity of the proteasome inhibitor bortezomib.

Characterization of the Rat Osteosarcoma Cell Line UMR-106 by Long-Read Technologies Identifies a Large Block of Amplified Genes Associated with Human Disease.

The rat osteosarcoma cell line UMR-106 is widely used for the study of bone cancer biology but it has not been well characterized with modern genomic methods. To better understand the biology of UMR-106 cells we used a combination of optical genome mapping (OGM), long-read sequencing nanopore sequencing and RNA sequencing.The UMR-106 genome was compared to a strain-matched Sprague-Dawley rat for variants associated with human osteosarcoma while expression data were contrasted with a public osteoblast dataset. Using the COSMIC database to identify the most affected genes in human osteosarcomas we found somatic mutations in Tp53 and H3f3a. OGM identified a relatively small number of differences between the cell line and a strain-matched control animal but did detect a ~45 Mb block of amplification that included Myc on chromosome 7 which was confirmed by long-read sequencing. The amplified region showed several blocks of non-contiguous rearranged sequence implying complex rearrangements during their formation and included 14 genes reported as biomarkers in human osteosarcoma, many of which also showed increased transcription. A comparison of 5mC methylation from the nanopore reads of tumor and control samples identified genes with distinct differences including the OS marker Cdkn2a. This dataset illustrates the value of long DNA methods for the characterization of cell lines and how inter-species analysis can inform us about the genetic nature underlying mutations that underpin specific tumor types. The data should be a valuable resource for investigators studying osteosarcoma, in general, and specifically the UMR-106 model.

A pan-cancer analysis ofWnt family member 7Bin human cancers.

Previous studies have highlighted the crucial role of Wnt7B in the development of various cancers, including breast, pancreatic, and gastric cancers. However, research into the involvement of Wnt7B is often confined to specific tumor types, with a noticeable lack of comprehensive studies spanning multiple cancer forms. The potential of Wnt7B as a diagnostic or prognostic cancer biomarker has not been fully explored. In this study, we combined bioinformatics and immunohistochemistry analyses to examine the expression patterns and functions of Wnt7B in cancerous and adjacent noncancerous tissues across a range of tumors. Our data indicate that Wnt7B may serve as a novel prognostic biomarker and therapeutic target in certain cancers. We found significant upregulation of Wnt7B expression levels in the majority of cancer cases examined. Furthermore, Wnt7B can influence cancer prognosis by modulating the tumor microenvironment, immune cell infiltration, and tumor stemness, among other factors. Additionally, we examined the associations between anticancer drug sensitivity and Wnt7B expression, which could aid in the development of more precise clinical therapies.

Aneuploidy in neoplasia: Single-cell data on 83,862 tumors.

Chromosomal aneuploidy, that is, numerical chromosome aberrations, is one of the molecular hallmarks of cancer. However, when neoplasms are studied with sequencing- and array-based approaches, chromosome numbers and ploidy states are typically inferred from bulk DNA data. Furthermore, published molecular estimates of neoplasia-associated aneuploidy often also include genomic imbalances resulting from various types of structural rearrangement, which likely result from other mechanisms than numerical chromosome aberrations. We thus analyzed chromosome numbers using single-cell cytogenetic data from 83,862 tumors, and show that both benign and malignant tumors are highly heterogeneous with regard to deviations from the normal, diploid state. Focusing on the chromosome numbers in 112 specific tumor types, defined by both exact morphologic diagnosis and organ location and from which data from ≥50 cases were available, we found two major clusters: one predominated by near-diploid neoplasms and one by neoplasms with extensive aneuploidy and one or more whole genome doublings. The former cluster included most benign solid tumors, myeloid neoplasms, and malignant gene fusion-associated solid tumors, whereas the latter was predominated by malignant solid tumors and lymphomas. For 16 malignant tumor types, the distribution of chromosome numbers could be compared to TCGA ploidy level data. Cytogenetic and molecular data correlated well, but the former indicates a higher level of clonal heterogeneity. The results presented here suggest shared pathogenetic mechanisms in certain tumor types and provide a reference for molecular analyses.

Racial distribution of molecularly classified brain tumors.

In many cancers, specific subtypes are more prevalent in specific racial backgrounds. However, little is known about the racial distribution of specific molecular types of brain tumors. Public data repositories lack data on many brain tumor subtypes as well as diagnostic annotation using the current World Health Organization classification. A better understanding of the prevalence of brain tumors in different racial backgrounds may provide insight into tumor predisposition and development, and improve prevention. We retrospectively analyzed the racial distribution of 1709 primary brain tumors classified by their methylation profiles using clinically validated whole genome DNA methylation. Self-reported race was obtained from medical records. Our cohort included 82% White, 10% Black, and 8% Asian patients with 74% of patients reporting their race. There was a significant difference in the racial distribution of specific types of brain tumors. Blacks were overrepresented in pituitary adenomas (35%, P < .001), with the largest proportion of FSH/LH subtype. Whites were underrepresented at 47% of all pituitary adenoma patients (P < .001). Glioblastoma (GBM) IDH wild-type showed an enrichment of Whites, at 90% (P < .001), and a significantly smaller percentage of Blacks, at 3% (P < .001). Molecularly classified brain tumor groups and subgroups show different distributions among the three main racial backgrounds suggesting the contribution of race to brain tumor development.

Endoscopic ultrasound-guided bite-on-bite biopsy and endoscopic ultrasound-guided fine-needle aspiration in the diagnosis of gastric tumors with negative malignant endoscopy biopsies: a retrospective cohort study

Background Specific types of gastric tumors, including gastric linitis plastica and lymphoma, may cause extensive deep-layer infiltration, impeding an accurate diagnosis with endoscopic biopsy. This study aims to evaluate the efficacy of endoscopic ultrasound (EUS)-guided bite-on-bite biopsy and EUS-guided fine-needle aspiration (EUS-FNA) in diagnosing gastric malignancies with negative endoscopic biopsies. Methods We retrospectively analyzed suspicious malignant gastric lesion cases in our hospital from October 2017 to August 2023. Clinical manifestations, radiographical examinations, endoscopic examinations, histopathological results, and therapeutic strategies were recorded and analyzed. Results Forty malignant gastric tumor cases with negative endoscopic biopsies were incorporated into our study. EUS-guided bite-on-bite biopsy was performed in 16 cases exclusively, whereas 17 patients received EUS-FNA exclusively, and seven patients underwent both simultaneously. Among the 23 patients who received the EUS-guided bite-on-bite biopsy, 22 (95.7%) were diagnosed with malignancies. Among the 24 patients who received EUS-FNA, a total of 19 cases with malignancies (79.2%) were confirmed by EUS-FNA (p = 0.11): 13 gastric adenocarcinomas, five metastatic malignancies, and one malignant stromal tumor. No adverse events were observed in any of the cases. Conclusions EUS-guided bite-on-bite biopsy and EUS-FNA possess their advantages and disadvantages. EUS-guided bite-on-bite biopsy could serve as a reliable diagnostic method for shallow lesions with negative malignant endoscopic biopsies.

Approaches to supratentorial brain tumours in children.

The differential diagnosis of supratentorial brain tumours in children can be challenging, especially considering the recent changes to the WHO classification of CNS tumours published in 2021. Many new tumour types have been proposed which frequently present in children and young adults and their imaging features are currently being described by the neuroradiology community.The purpose of this article is to provide guidance to residents and fellows new to the field of paediatric neuroradiology on how to evaluate an MRI of a patient with a newly diagnosed supratentorial tumour. Six different approaches are discussed including: 1. Tumour types, briefly discussing the main changes to the recent WHO classification of CNS tumours, 2. Patient age and its influence on incidence rates of specific tumour types, 3. Growth patterns, 4. Tumour location and how defining the correct location helps in narrowing down the differential diagnoses and 5. Imaging features of the tumour on DWI, SWI, FLAIR and post contrast sequences.

MDB-50. CAR-T CELL-DERIVED EXOSOMES LOADED WITH THERAPEUTIC SIRNA IS A PROMISING TECHNIQUE IN THE TREATMENT OF SUBGROUP 3 MEDULLOBLASTOMA

Abstract Medulloblastoma (MB) is a childhood life-threatening tumor that occurs in the cerebellum. This tumor showed resistance against several types of immunotherapies like anti-PD1, cancer vaccines, monoclonal antibodies (mAbs), and even CAR-T cells. Subgroup 3 MB is the worst threatening subtype that poorly responds to treatment. Interestingly, our data showed that the HLX gene a transcription factor that regulates cell growth is highly expressed in G3-MB and associated with poor prognosis. The siRNA-HLX inhibited tumor growth in vitro and in vivo and promisingly showed long survival in the immunocompetent mouse model. We developed CAR-T-Exosomes that can pass brain-blood barriers (BBB) and deliver therapeutic siRNA to the brain tumor. Further analysis revealed that CAR-T-Exosomes contain T cell cytotoxicity materials that can destroy tumor cells and induce anti-tumor immune response. Promisingly, the expression of HLX was significantly inhibited in the tumor cells and the anti-tumor immune response was enhanced. CAR-T-Exosomes have high safety and can induce anti-tumor response without stimulation of immunotoxicity side effects like cytokine release syndrome (CRS). In this study, we are highlighting anti-EPHA2-CAR-Exosomes as a highly specific type of tumor CAR-T-Exos immunotherapy due to a very low expression of EPHA2 in normal cells and overexpression in medulloblastoma, particularly G3-MB. Therefore, we speculate significant inhibition of tumor growth and activation of CTL effector cells in the tumor microenvironment. This study provides a new biological technique for delivering tumor suppressor RNAs and developing specific anti-tumor immune responses. Indeed, the promising safety of anti-EPHA2-CAR-T cell exosomes compared to cell-based immunotherapy.

Ubiquitin ligase subunit FBXO9 inhibits V-ATPase assembly and lung cancer metastasis.

e20520 Background: The evolutionarily conserved protein FBXO9 acts as a substrate receptor for the SKP1-cullin-1-RBX1 ubiquitin ligase and is implicated in cancer, exhibiting either tumor-suppressive or oncogenic effects depending on the specific tumor type. However, their role in lung cancer metastasis remains unclear. Methods: Lentiviral vectors carrying miRNA-based shRNA sequences for gene-specific knockdown were generated, and Lenti-CRISPR-Cas9 vectors containing gene-specific sgRNA sequences were designed. Gene overexpression was achieved using doxycycline-inducible lentiviral constructs, while gene knockdown or knockout cells were generated using shRNA and CRISPR-Cas9, respectively. Functional assays included migration, clonogenic survival assays, tumor sphere assays, and protein interaction studies using mass spectrometry, immunoprecipitation, and immunoblot analysis. Results: This study identified FBXO9 as a crucial regulator that suppresses lung cancer cell migration, tumor sphere growth and restricts metastasis. We showed that FBXO9 facilitates the ubiquitination of the catalytic subunit A (ATP6V1A) of the Vacuolar-type H+-ATPase (V-ATPase), resulting in its interaction with the cytoplasmic chaperone HSPA8 and subsequent sequestration within the cytoplasm. This process hinders the assembly of functional V-ATPase, resulting in reduced vesicular acidification. In contrast, depletion of FBXO9 reduced ATP6V1A ubiquitination, resulting in increased V-ATPase assembly and vesicular acidification, thus promoting pro-metastatic Wnt signaling and metastasis of lung cancer cells. Furthermore, we demonstrated the effectiveness of inhibitors targeting V-ATPase in inhibiting lung cancer metastasis in a mouse model. Finally, we established a correlation between lower FBXO9 levels and poorer survival outcomes in patients with lung cancer. Conclusions: These findings collectively elucidate the critical role of FBXO9 in regulating V-ATPase assembly and provide a molecular basis for FBXO9's function in inhibiting lung cancer metastasis. This highlights the potential therapeutic opportunities of FBXO9 supplementation.

A first-in-human phase I study of ATG-031, anti-CD24 antibody, in patients with advanced solid tumors or B-cell non-Hodgkin lymphomas (PERFORM).

TPS2691 Background: ATG-031 is a first-in-class humanized cluster of differentiation 24 (CD24) antibody. By disrupting the interaction between CD24, a ‘do not eat me’ signal on cancer cells, and the inhibitory receptor Siglec-10 on tumor-associated macrophages (TAMs), it enhances macrophage-mediated phagocytosis of cancer cells and promotes cytotoxic T cell function in the tumor microenvironment. ATG-031 also triggers antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) towards target tumor cells through its immunoglobulin gamma 1 (IgG1) Fc-dependent effects. Preclinical studies indicated that ATG-031-induced phagocytosis transforms macrophages from a tumor-tolerant M2 phenotype to an antitumor M1 phenotype, significantly inhibiting tumor growth both as monotherapy and synergistically with immune checkpoint inhibitors (ICI) and/or chemotherapies in mouse models. Methods: ATG-031 is undergoing evaluation for safety and preliminary antitumor efficacy in a Phase I, multi-center, open-label clinical study, PERFORM (NCT04986865), in patients with advanced solid tumors or B-cell non-Hodgkin’s lymphoma. The study includes a dose escalation phase and a dose expansion phase. The dose escalation phase enrolls patients with advanced solid tumors (preferred tumor types: lung cancer, breast cancer, ovarian cancer, urothelial cancer, and liver cancer) using a Bayesian Optimal Interval (BOIN) design with 3 to 9 patients at each dose level. A priming dose, defined as an initial lower dose followed by escalation to the full treatment dose, will be applied if Grade ≥2 cytokine release syndrome (CRS) is observed during the dose-limiting toxicity (DLT) period. The dose expansion phase will enroll patients with specific tumor types and will randomize patients into two or more dose levels to determine the recommended Phase II dose (RP2D). The PERFORM study explores an intravenous dose of ATG-031 once every 21 days (1 cycle) to assess DLT during the first two treatment cycles in dose escalation. Key inclusion criteria include histological or cytological confirmation of a solid tumor that has relapsed or has been refractory to standard therapy, at least one measurable lesion per RECIST, and an ECOG performance status of 0 to 1. The study excludes patients with CNS malignancies and those who have experienced Grade ≥3 immune-related adverse events (irAEs) or irAEs leading to prior immunotherapy discontinuation. As of January 2024, 2 sites in the United States have initiated the study, and 4 patients have received ATG-031 treatment at 0.03mg/kg (dose level 1). Clinical trial information: NCT04986865 .