Aggressive Tumor Research Articles

A Rare Case of an Aggressive Mixed Germ Cell Tumor Following Testicular Torsion

A Rare Case of an Aggressive Mixed Germ Cell Tumor Following Testicular Torsion

Abstract C002: CKLF attracts CCR4-expressing CD4+ cells to foster immune repression and tumor aggressiveness in MYCN-driven neuroblastoma

Abstract Neuroblastoma, especially those with aberrant MYCN activation, often harbor an immunosuppressive microenvironment to fuel malignant growth and trigger treatment resistance. Despite this knowledge, there are no effective strategies to tackle this problem. Here we combined analyses of human neuroblastoma with live tracking and functional studies of the tumor microenvironment (TME) in zebrafish. We identified chemokine-like factor (CKLF) as a key driver of MYCN-mediated immunosuppression and neuroblastoma aggression. We showed that human MYCN-activated neuroblastoma upregulates and secretes CKLF, which is a reliable predictor of poor patient survival. Analysis of primary patient samples demonstrates a strong positive association between MYCN and CKLF expression in neuroblastoma cells together with the enrichment of FOXP3+ T cells in the TME. Taking advantage of in vivo zebrafish models of MYCN-driven neuroblastoma that resemble human high-risk disease, we demonstrated that cklf overexpression in zebrafish neural crest cells induces an immunosuppressive TME while promoting rapid tumor onset and progression. We also demonstrated that as early as the premalignant stage, tumor cells secrete CKLF to attract CCR4-expressing Cd4+ cells to induce immunosuppression and tumor aggression. Conversely, genetic depletion of cklf in tumor cells reduces the recruitment of Cd4+ cells to the TME while increasing cytotoxic Cd8+ and natural killer cells infiltration, inhibiting neuroblastoma development in zebrafish. Our work provides the first example that MYCN can activate CKLF to allure CD4+ immune cells to the TME and incite immunosuppression, positioning CKLF as a potential novel immunotherapeutic target for the treatment of MYCN-driven high-risk neuroblastoma. Citation Format: Xiaodan Qin, Hui Feng, Andrew Lam, Xu Zhang, Satyaki Sengupta, Bryan Iorgulescu, Sanjukta Das, Zhenwei Zhou, Tao Zuo, Grace Meara, Madison Rager, Alexander Floru, Hongru Ni, Chinyere Kemet, Divya Veerapaneni, Daniel Kashy, Liang Lin, Kenneth Lloyd, Lauren Kwok, Kaylee Smith, Raghavendar Nagaraju, Rob Meijers, Craig Ceol, Ching-Ti Liu, Sanda Alexandrescu, Catherine J. Wu, Derin Keskin, Rani George. CKLF attracts CCR4-expressing CD4+ cells to foster immune repression and tumor aggressiveness in MYCN-driven neuroblastoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr C002.

Abstract C050: Leveraging ECM deposition by CAF-like Ewing sarcoma tumor cells to target micrometastases with matrix-binding VHHs

Abstract Ewing sarcoma (EwS) is an aggressive bone and soft tissue tumor and EwS patients often succumb to their disease years after initial treatment due to relapses at metastatic sites. Novel therapeutic strategies are needed that can successfully eliminate microscopic residual disease foci that persist at the end of primary therapy. Extracellular matrix (ECM) proteins in the tumor microenvironment (TME) provide critical pro-survival and pro-invasion signals to tumor cells. Our published and unpublished data show that the glycoprotein tenascin-C (TNC) is enriched in EwS metastases and that TNC and other pro-tumorigenic ECM proteins are deposited by subpopulations of CAF-like tumor cells that are activated in response to tumor and TME-derived TGF-beta ligands. TNC is abundantly produced by multiple human tumors of epithelial and non-epithelial lineage but is otherwise rarely expressed outside of development and wound healing. Importantly, TNC is specifically enriched in metastatic lesions where it has been implicated as a mediator of metastatic competence and treatment resistance. In the current work we have tested whether the TNC-rich TME of disseminated EwS tumor foci could be leveraged to direct therapies to sites of residual micrometastatic disease. To achieve this, we generated monovalent and bivalent anti-human TNC VHHs (hTNC-VHH) using a mammalian expression platform. Camelid-derived hTNC-VHH sequences were sourced from published literature. VHHs are single domain heavy chain only antibody fragments with higher stability and tissue penetration than conventional monoclonal antibodies. Using EwS tumor spheroids in collagen-rich 3D culture, hTNC-VHH penetrated dense ECM matrices and bound through multiple cell layers in under 10 minutes. hTNC-VHH accumulated in TNC-positive but not TNC-knockout EwS spheroids and were retained beyond 96 hours. To assess their potential to drive protein and immune therapies to TNC-rich TMEs, we fused hTNC-VHH to immune modulating CD3- and CD28-activating VHHs. These hTNC-VHH-CD3/CD28-conjugates promoted immune cell activation and tumor cell death in PBMC-tumor co-culture assays as determined by CD25 flow cytometry and fluorescence microscopy, respectively. To assess in vivo localization, fluorescently-tagged hTNC-VHH were intravenously injected into mice that had been xenografted with EwS cells. Tissue microscopy confirmed selective binding of hTNC-VHH to small lung and liver EwS micrometastases in less than 4 hours. VHHs were not retained in non-tumor bearing organs including the brain and heart or in tumor-free lung and liver regions. Experiments are ongoing to assess anti-tumor efficacy and pharmacodynamics of hTNC-VHH conjugates in EwS xenografts. Together these findings suggest that the ECM-remodeling properties of CAF-like EwS cells can be exploited to recruit novel ECM-targeting protein therapeutics to micrometastases. If successful, this innovative approach could eradicate microscopic residual disease and prevent metastatic EwS recurrence. Citation Format: Emma D. Wrenn, Jason P. Price, Raymond O. Ruff, Nicolas M. Garcia, James M. Olson, Elizabeth R. Lawlor. Leveraging ECM deposition by CAF-like Ewing sarcoma tumor cells to target micrometastases with matrix-binding VHHs [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr C050.

Abstract A021: HRI inhibition by hemin as a novel targeted therapy for glioblastoma via the integrated stress response

Abstract The treatment of glioblastoma (GBM), a highly malignant brain tumor, is critically hindered by the ineffectiveness of current modalities such as surgery, radiation, and chemotherapy. These traditional methods fail to completely remove the tumor mass and lack the ability to discriminate between cancerous and normal brain cells, often resulting in damage to healthy tissue and recurrence of the disease. This underscores an urgent necessity to develop novel therapeutic strategies that can target tumor cells with precision, offering hope for improved survival rates and quality of life for GBM patients. This study investigates targeted therapy, focusing on the Integrated Stress Response (ISR) that cancer cells harness to survive hypoxic stress. Specifically, it demonstrates that EIF2AK1, which encodes Heme-regulated eIF2α kinase (HRI), is activated under hypoxia and co-expressed with the glioma stem cell marker SOX2, which specifically happens in glioma cells, increasing the targeted accuracy of the repurposing drug. This correlation, indicating hypoxia-driven stemness, is confirmed at both the genetic level and through Gene Set Enrichment Analysis (GSEA). Furthermore, GSEA in Spatial Transcriptomics shows hypoxia-induced glycolysis, disrupting the tumor microenvironment and causing necrotic cell death. Stemness phenotype is induced in the peripheral cells due to the unfavorable hypoxic environment. Hemin, an HRI inhibitor, has been repurposed to inhibit ISR and mitigate hypoxia. Treatment with Hemin on the U87 cell line resulted in IC50 values of 23.50 µM and 52.46 µM at 24 and 48 hours, respectively, surpassing Temozolomide's efficacy. A decrease in HRI expression after the Hemin treatment suggests the and ISR activity and, potentially, hypoxia. This would reverse the unfavorable microenvironment so that the stemness phenotype doesn’t spread. Potentially, invasiveness and recurrences of GBM in clinic situation would decrease, thus potentially improving patient prognosis. The therapeutic potential of Hemin is enhanced by its ability to kill glioma cells directly and accurately in the glioma cell in original TME when cells are proliferating with adequate oxygen. Therefore, this study demonstrates the therapeutic potential of repurposing Hemin, an HRI inhibitor, to precisely target hypoxia-induced glioma stem cells in glioblastomas, disrupting the aggressive tumor microenvironment to potentially improve patient prognosis. Citation Format: Xingchuan Ma. HRI inhibition by hemin as a novel targeted therapy for glioblastoma via the integrated stress response [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr A021.

Abstract B043: BDNF-TrkB.T1 signaling increases neutrophil recruitment and epithelial-to- mesenchymal transition in gliomas

Abstract Gliomas are the most common type of brain tumor in both children and adults. Communication between glioma cells and the brain tumor microenvironment (TME) is a fundamental aspect of brain cancer pathophysiology. Glioma cells secrete factors that act as chemoattractants, influencing the TME. In addition, neuronal activity within the TME drives the proliferation and growth of gliomas through paracrine signaling, with brain-derived neurotrophic factor (BDNF) being a key mediator. BDNF binds with high affinity to the tropomyosin receptor kinase B (TrkB). Recent work from our group has demonstrated that the TrkB.T1 splice variant is upregulated in human gliomas. Furthermore, TrkB.T1 overexpression enhances tumor aggressiveness in vivo and is associated with the downregulation of genes involved in tumor cell recognition and elimination. However, the role of the TrkB.T1 splice variant in the bidirectional communication between glioma cells and the surrounding microenvironment remains unexplored. Our aim was to investigate whether the increased levels of TrkB.T1 observed in gliomas contribute to modulating immune responses. We investigated the immune cell heterogeneity associated with elevated TrkB.T1 levels in vivo using a glioma mouse model engineered with RCAS/tv-a technology. Tumors overexpressing TrkB.T1 exhibited increased neutrophil recruitment, a phenomenon linked to tumor growth, metastasis and therapeutic resistance. To further dissect the signaling mechanisms underlying the BDNF-TrkB.T1 axis, we conducted in vitro studies using glioma stem cells (GSCs) that express high levels of TrkB.T1. GSCs were treated with BDNF, after which the conditioned media was analyzed using a cytokine multiplex assay, and cell lysates were subjected to proteomic analysis. Our findings revealed that TrkB.T1 significantly upregulates key chemokines previously implicated in neutrophil recruitment. Moreover, BDNF signaling increased the expression of N-cadherin, β- catenin, and Snail, markers indicative of the epithelial-to-mesenchymal transition (EMT) phenotype. To further explore the role of TrkB.T1, we used CRISPR/Cas9-based genome editing to knock down TrkB.T1 in GSCs. In conclusion, our findings suggest that the highly expressed TrkB.T1 receptor in gliomas contributes to creating an immunosuppressive microenvironment by recruiting neutrophils and promoting EMT. These insights highlight TrkB.T1 as a potential therapeutic target for modulating glioma-immune cell interactions, which could be crucial in curbing disease progression. Citation Format: Leyre Merino-Galan, Sergio Ortiz-Espinosa, Hawa L. Jagana, John M. Hemenway, Ashmitha Rajendran, Taylor S. Jackson, Daniel A. Kuppers, Sonali Arora, Patrick J. Paddison, Siobhan S. Pattwell. BDNF-TrkB.T1 signaling increases neutrophil recruitment and epithelial-to- mesenchymal transition in gliomas [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr B043.

Abstract A009: PIEZO1 driven tumor aggressiveness in an organ-on-chip model of colorectal cancer

Abstract Mechanical forces have long been known to affect the progression of cancer, however exact study of the specific consequences of these forces has been hampered by currently available model systems. Traditional cell culture models often lack the ability to incorporate physiologically relevant mechanical forces, and animal models offer too much complexity to be able to effectively isolate and study the mechanical forces. Organ-on-chip (OOC) technology allows for the integration of human relevant physiological forces in a setting conducive to their study. Here, we explore how the early metastatic spread of colorectal cancer (CRC) can be influenced by physiological mechanical forces. Specifically, we investigated the ability of peristaltic motions, responsible for natural bowel motility, to enhance the invasive capability of colon tumor cells. Our microfluidic OOC model comprises of an epithelial channel and endothelial channel separated by a porous membrane allowing for biological and chemical crosstalk between them. Vacuum channels spanning the length of the structure allow force to applied in a cyclic manner mimicking peristaltic contraction and relaxation. Our OOC model supports the addition of tumor microenvironment (TME) components in a piece-wise manner to better understand how specific factors influence the behavior of tumor cells. Analyzing gene and protein expression levels, we have found that peristaltic-like motions induce changes in the Hippo signaling and epithelial-to-mesenchymal (EMT) pathways resulting in greater invasion of tumor cells into the endothelial compartment as observed by on-chip confocal imaging. Moreover, knock down studies have demonstrated that the response to peristaltic-like stretch is driven through a PIEZO1-mediated mechanism. Furthermore, to increase the physiological relevance of our model, we administered peripheral blood mononuclear cells (PBMCs) to the endothelial channel to simulate aspects of the immune TME. Preliminary studies revealed that the recruitment of PBMCs can be altered by the presence of peristaltic-like stretch. Our findings demonstrate that mechanical forces in the CRC TME can dramatically alter tumor behavior as shown in our CRC-OOC model. Citation Format: Curran A. Shah, Carly R. Strelez, Aaron Schatz, Hannah Jiang, Rachel Perez, Shannon M. Mumenthaler. PIEZO1 driven tumor aggressiveness in an organ-on-chip model of colorectal cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr A009.

Glioblastoma and its interaction with neurogenesis

Glioblastoma (GBM) is the most frequent and aggressive malignant primary tumor of the central nervous system in adults, with an incidence of 3.23 per 100,000 people. Despite the existence of various therapeutic approaches, the absence of a cure and the unfavorable prognosis persist for this neoplasm, with a median survival of approximately 8-15 months and a 5-year survival rate of 6.9%. In this review, we address the epidemiology, histopathology, molecular characteristics, and treatment of GBM. We highlight the relationship of GBM with the microenvironment in the lateral ventricle wall and the cerebrospinal fluid. The location of GBM in this region results in more aggressive tumors and shorter life expectancy for patients. Understanding the malignancy mechanisms that hinder remission, treatment, and positive prognosis opens the possibility of improving diagnostic and therapeutic interventions against GBM.

Proportion of Gleason Score ≥8 Prostate Cancer on Biopsy and Tumor Aggressiveness in Matched Cohorts of East Asian and Non-East Asian Men.

Historically, Asia had a lower prostate cancer (PCa) incidence and mortality compared with Western countries, but the gap is narrowing. Paradoxically, Asians have been reported to present with more advanced disease though more favorable outcomes. Despite PCa becoming an emerging health priority in East Asia, our knowledge remains limited. We compared the prevalence of high-grade PCa on biopsy and disease progression after radical prostatectomy (RP) in East Asian men from Asia and non-East Asian men from Western countries. This retrospective cohort study included men who underwent prostate biopsy and RP at academic centers in Shanghai, China, and Toronto, Canada (2014-2019). The expanded RP cohort included East Asian men from Singapore (n=282) and non-East Asians from Paris (n=192). Primary endpoints included the proportion of men with Gleason score (GS) ≥8 on biopsy and metastasis-free survival (MFS) after RP for GS ≥8. Multivariable logistic regression and Cox proportional hazard models were performed. Propensity score matching was used to reduce imbalances between cohorts. PCa was found on biopsy in 2,343 of 4,905 (48%) East Asians and 2,317 of 3,482 (67%) non-East Asians (P<.001). Prostate-specific antigen (PSA) levels at presentation and the proportion of men with GS ≥8 were higher in East Asians than non-East Asians (12.4 vs 6.6 ng/mL and 15.0% vs 8.8%, respectively; both P<.001). On multivariable analysis, there was no difference in the proportion of men with GS ≥8 between matched cohorts with PSA <20 ng/mL (n=3,572; odds ratio, 1.05 [95% CI, 0.77-1.43]; P=.76). No difference in MFS was found after RP between matched cohorts (hazard ratio, 0.97 [95% CI, 0.55-1.70]; P=.92). This contemporary study demonstrates that East Asian men are equally as likely to harbor aggressive PCa on biopsy as non-East Asian men at PSA levels observed in screening programs, with no difference in disease aggressiveness after RP. The assumption that unfavorable PCa at diagnosis is more common but less aggressive in East Asians should be revisited and viewed in the context of the expected increase in the PCa burden worldwide.

Identification of PDLIM1 as a glioblastoma stem cell marker driving tumorigenesis and chemoresistance.

Glioblastoma (GBM) is an aggressive brain tumor with a poor prognosis, largely due to the presence of glioblastoma stem cells (GSCs). These cells drive tumor progression, recurrence, and chemoresistance, making them critical targets for therapy. This study aims to identify novel GSC markers for improved diagnosis and targeted treatment. We utilized single-cell RNA sequencing (scRNA-seq) and bulk RNA-seq data to identify PDLIM1 as a novel GSC marker. PDLIM1 was specifically expressed in GSCs and was associated with poor prognosis and advanced tumor stages. Functional assays demonstrated that PDLIM1 overexpression enhanced GBM cell proliferation, reduced apoptosis, increased GSC proportions, and promoted chemoresistance and tumorigenesis. Conversely, PDLIM1 knockdown inhibited these processes. Mechanistically, PDLIM1 was found to exert its effects likely by promoting the PI3K-AKT pathway. In conclusion, PDLIM1 may serve as a potential marker of GSCs associated with poor prognosis, tumorigenesis, and chemoresistance in GBM, representing a potential therapeutic target for improving GBM patient outcomes.

Innovations in intraoperative therapies in neurosurgical oncology: a narrative review.

High-grade gliomas (HGG) represent the most aggressive primary brain tumors in adults, characterized by high recurrence rates due to incomplete resection. This review explores the effectiveness of emerging intraoperative therapies that may extend survival by targeting residual tumor cells. The main research question addressed is: What recent intraoperative techniques show promise for complementing surgical resection in HGG treatment? A comprehensive literature review was conducted, examining recent studies on intraoperative therapeutic modalities that support surgical resection of HGG. Techniques reviewed include laser interstitial thermal therapy (LITT), intraoperative brachytherapy, photodynamic therapy (PDT), sonodynamic therapy (SDT), and focused ultrasound (FUS). Each modality was evaluated based on clinical application, evidence of effectiveness, and potential for integration into standard HGG treatment protocols. Findings indicate that these therapies offer distinct mechanisms to target residual tumor cells: LITT provides localized thermal ablation; intraoperative brachytherapy delivers sustained radiation; PDT and SDT activate cytotoxic agents in tumor cells; and FUS enables precise energy delivery. Each method has shown varying levels of clinical success, with PDT and LITT currently more widely implemented, while SDT and FUS are promising but under investigation. Intraoperative therapies hold potential to improve surgical outcomes for HGG by reducing residual tumor burden. While further clinical studies are needed to optimize these techniques, early evidence supports their potential to enhance the effectiveness of surgical resection and improve patient survival in HGG management.

Single-cell transcriptomics link gene expression signatures to clinicopathological features of gonadotroph and lactotroph PitNET.

Pituitary neuroendocrine tumors (PitNET) are among the most common intracranial tumors. Despite a frequent benign course, aggressive behavior can occur. Tumor behavior is known to be under the influence of the tumor microenvironment (TME). However, the relationship between TME cells and aggressive tumor behavior has not been adequately explored in PitNET. We performed differential expression analysis as well as gene expression program identification based on single-cell RNA sequencing to comparatively characterize the transcriptome of seven gonadotroph and three lactotroph PitNET and correlate it with clinical features using bulk RNA-seq data from an independent cohort of 134 PitNET. Tumor immune infiltration was quantified via immunostaining on tissue sections of gonadotroph and lactotroph PitNET. In lactotroph PitNET, we detect a highly proliferative gene profile with significantly increased expression levels in aggressively growing tumors within bulk RNA-seq data of an independent cohort of 134 PitNET samples. We also report high intratumoral heterogeneity in gonadotroph PitNET (GoPN) and lactotroph PitNET (LaPN) and identify signatures of epithelial, endocrine, and immunological gene networks in both subtypes. A comparison of their TME composition shows enrichment of SPP1+ macrophages and CD4+ T cells in GoPN, as well as enrichment of CD4/CD8 double-negative T cells (DN) and natural killer cells (NK) in LaPN. Also notable is the presence of proliferative lymphocytes, the occurrence of which positively correlates with more aggressive tumor behavior in the bulk RNA-seq cohort. However, increased CD8+ T and NK cell abundances correlate significantly with reduced aggressiveness indicating potential anti-tumoral effects. Our study expands the knowledge of the differences in cellular composition of gonadotroph and lactotroph PitNET subtypes. It lays the foundation for further studies on the influence of lymphoid cells on the variable aggressive behavior of PitNET. Regarding the treatment of drug-resistant lactotroph PitNET, proliferative lymphocytes, CD8+ T, and NK cells could represent potentially valuable targets for developing new cancer immunotherapies.

A Systemic Review on Phytochemicals and Novel Approaches for the Management of Hepatic Cancer

Introduction: Hepatic cancer, an aggressive tumour that often develops along with cirrhosis and chronic liver disease like infections with the hepatitis B and hepatitis C viruses, while nonalcoholic steatohepatitis, is linked to metabolic syndrome or diabetes mellitus. It is the third most prevalent cause of cancer-related mortality globally and ranks fifth in cancer incidence. According to GLOBOCON, the prevalence is expected to rise by 55.0% and the fatalities by 56.4% in the near future. Objective: The present review offered natural plant-based substances and compounds having curative effects on liver cancer, along with novel drug delivery systems and nanocarrier-based therapies. Methods: The literature has been taken from PubMed, Google Scholar, SciFinder, Springer Nature, Bentham Science, PLOS one, or other internet sites. Result: Treatment for heterogeneous malignancy is multidimensional, and care guidelines differ depending on the specialty and location. Several nutritional herbal remedies and their active phytoconstituents may have an abundance of impacts on the management of liver cancer, including preventing the growth and spread of tumor cells, shielding the body from liver carcinogens, boosting the effects of chemotherapy and immunomodulating the body. Conclusion: The treatment of liver cancer involves multidisciplinary and multimodel therapy. The literature is a compilation of extract, compounds, and novel approaches like nanoparticles, microsphere, liposomes, niosomes, phytosomes and microparticles. These approaches not only manage cancer but also boost the immunity of the individuals.

A novel mouse model recapitulating the MMR-defective SCLC subtype uncovers an actionable sensitivity to immune checkpoint blockade.

Small cell lung cancer (SCLC) has an extremely poor prognosis. Despite high initial response rates to chemotherapy and modest survival improvements with the addition of immune checkpoint inhibitors (ICI), almost all patients experience relapse and fatal outcomes. Recent genomic insights uncovered extensive molecular heterogeneity in addition to the almost uniform loss of RB1 and TRP53. Additionally, defective DNA mismatch repair (MMR) has recently been described in some SCLC cases. Here, we generated a novel SCLC mouse model capturing MMR deficiency and assessed immunotherapy responses. We developed an MMR-deficient genetically engineered mouse model (GEMM) of SCLC by introducing a conditional Msh2 gene, crucial for maintaining MMR integrity, into the standard Rb1fl/fl;Trp53fl/fl (RP) model. Genomic characteristics and preclinical therapy responses were evaluated by focusing on overall survival and whole exome sequencing (WES) analyses. MMR-defective SCLC tumors (Rb1fl/fl;Trp53fl/fl;Msh2fl/fl (RPM)) developed later than tumors in MMR-proficient mice. However, the time from tumor manifestation to death of the affected animals was substantially shortened (median survival 55 days in RP vs. 46.5 days in RPM), indicating increased aggressiveness of MMR-defective tumors. RPM tumors exhibited MMR deficiency, high tumor mutational burden (TMB), and an elevated load of candidate neoantigens, compared to RP lesions (p = 0.0106), suggesting increased immunogenicity. Importantly, the overall survival of RPM animals was significantly improved when exposed to ICI. We propose a novel RPM mouse model as a suitable system to mimic MMR-defective SCLC and tumors with high TMB. We provide in vivo evidence that Msh2 deficiency enhances ICI sensitivity. These findings could contribute to stratifying SCLC patients to immunotherapy, thereby improving treatment outcomes.

Postoperative NEOadjuvant TEMozolomide followed by chemoradiotherapy vs. upfront chemoradiotherapy for Glioblastoma multiforme (NEOTEM) trial: interim results

Abstract Background Glioblastoma (GBM) is an aggressive brain tumor with poor survival rates despite current treatments. The standard of care (SOC) includes surgery, followed by radiotherapy plus concurrent and adjuvant chemotherapy with temozolomide (TMZ). This phase II trial assessed the safety and efficacy of neoadjuvant TMZ (nTMZ) before and during chemoradiotherapy in newly diagnosed GBM patients. Methods Newly diagnosed GBM patients who underwent maximal safe resection were randomized into two groups. One received nTMZ before standard chemoradiotherapy and adjuvant TMZ (intervention). The other received standard chemoradiotherapy followed by adjuvant TMZ (control). Primary endpoints were progression-free survival (PFS) at 6 and 12 months. Secondary endpoints included overall survival, radiological and clinical responses, and adverse events. Results Of 35 patients, 16 were in the intervention group and 19 in the control group. Median PFS was 3 months [95%CI:1.98-4.01] and 9 months [95%CI: 3.93-14.06] in the intervention and control group, with a high progression rate (73.4%) during nTMZ treatment. The 6-month PFS rates were 58% vs. 25% (P=0.042), and 12-month PFS rates were 26% vs. 25% (P=0.039) in the control and intervention groups. Patients with unmethylated MGMT, poor performance status (PS), or those undergoing biopsy or subtotal resection had worse PFS with nTMZ. Adverse events were similar between groups. Conclusions Neoadjuvant TMZ before SOC chemoradiotherapy did not improve outcomes for newly diagnosed GBM patients and is unsuitable for those with unmethylated MGMT or poor PS. It may benefit patients with near or gross total resection. Further research is needed to refine GBM treatment strategies.

Serum lactate dehydrogenase as a prognostic marker for treatment response in IDH wild-type glioblastoma patients undergoing stupp protocol.

Elevated lactate dehydrogenase (LDH), a marker of tumor aggressiveness and metabolic alterations, may predict treatment response and overall survival across various tumors. This study investigates the correlation between serum LDH levels and clinical outcomes in glioblastoma patients treated with radiotherapy (RT) and temozolomide (TMZ). This retrospective study analysed patients with IDH wild-type glioblastoma (IDH-wt GB) treated at the Radiotherapy Department of Azienda Ospedaliero-Universitaria Senese from 2018 to 2023. Clinical data, including hematologic parameters (e.g., LDH), imaging (MRI), and MGMT promoter methylation status, were collected. All patients received RT and TMZ following the Stupp protocol. Serum LDH levels were measured one week before RT, and Radiological Response (RR) was assessed using RANO criteria. Overall survival (OS), progression-free survival (PFS), and RR were primary endpoints. Statistical analyses included Kaplan-Meier, Cox regression, and decision tree analysis for LDH cut-off determination. In a cohort of 147 IDH wild-type glioblastoma patients treated with the Stupp protocol, the median OS was 14 months and median PFS was 8 months. Elevated baseline LDH levels were associated with significantly poorer outcomes, showing a median OS of 9 months versus 20 months and a median PFS of 6 months versus 13 months for lower LDH levels (p < 0.001 and p = 0.0001, respectively). LDH levels also correlated with RR (p = 0,001), Multivariate analysis confirmed high LDH as an independent predictor of worse OS (HR = 2.31) and PFS (HR = 2.60), suggesting its utility as a prognostic biomarker. Elevated LDH levels before starting the Stupp protocol are clinically significant as they predict poorer overall survival and progression-free survival in glioblastoma patients and worse RR. Incorporating LDH measurements into treatment planning can help identify patients at higher risk of poor outcomes, allowing for more tailored and potentially aggressive treatment strategies to improve management and therapeutic responses in glioblastoma.

OGC SO04 - Impact of COVID-19 on Decision-making and Survival in Esophago-Gastric Cancer Treatment: Insights from a Multidisciplinary Approach

Abstract Background The COVID-19 pandemic necessitated rapid adaptation in healthcare delivery, affecting cancer care pathways. This study assesses the impact of these changes on multidisciplinary team (MDT) decision-making and survival outcomes in esophago-gastric cancer patients across pre-pandemic, peak pandemic, and post-pandemic periods. Method A retrospective cohort study involving patients referred to a UK tertiary EG cancer center during distinct six-month intervals mirroring the pandemic's evolution. Analysis focused on MDT recommendations, treatment pathways, and two-year survival rates, comparing deviations from standard care across periods. Results The study revealed a significant reduction in patient referrals and expedited treatment decisions during the pandemic peak, with a shift towards palliative care in post-pandemic cases. Although no statistically significant difference in two-year survival rates was observed, the post-pandemic period showed an increase in tumor aggressiveness and positive resection margins, suggesting potential long-term impacts of delayed diagnosis and treatment. Conclusion COVID-19 has significantly influenced MDT decision-making and patient pathways in esophago-gastric cancer care, underlining the necessity of resilient healthcare systems. Despite maintaining survival rates, the observed increase in tumor aggressiveness post-pandemic highlights the critical need for uninterrupted cancer diagnosis and treatment services during global health emergencies.

Abstract A052: Circulating tumor DNA (ctDNA) in plasma and urine of renal cell carcinoma patients with localized disease

Abstract Introduction: Circulating tumor DNA (ctDNA) is increasingly valuable in cancer care. Early diagnosis of renal cell carcinoma (RCC) significantly improves prognosis. Clear cell RCC (ccRCC), the most prevalent and aggressive subtype, often leads to recurrence in over 20% of localized cases post-nephrectomy. Thus, risk-stratifying tools are crucial for tailored treatment strategies. In this study, we tracked tumor mutations in DNA from plasma (ctDNA) and urine (utDNA) in patients with localized ccRCC to explore their potential as risk-stratifying biomarkers for recurrence. We evaluated ctDNA/utDNA pre-surgery in all RCC patients and conducted longitudinal assessments post-surgery in ccRCC patients. Additionally, for one ccRCC patient with aggressive disease, we analyzed tumor mutations in the plasma of patient- derived xenograft (PDX) replicates. Methodology: RCC patients were recruited from A.C.Camargo Cancer Center. Urine and plasma samples were taken pre-surgery (BL-baseline), and for ccRCC patients, samples were collected at 6-8 weeks and 6, 18 and 30 months post- surgery (M1, M2, M3 and M4, respectively). Patients were monitored for recurrence for up to 6,3 years. We used a customized 28-gene RCC panel and a commercial 409-gene solid tumor panel to identify tumor somatic mutations using Illumina NextSeq 500 and Ion S5 platforms, respectively. Tumor specific mutations were tracked in DNA from patient plasma and urine, and PDX plasma, using the PATS (Personalized amplicon target sequencing) method on Ion S5 Plus platform. Results: Out of 79 RCC patients (58% ccRCC), 57 (72%) had tumor somatic mutations, including 39 (68%) in ccRCC. VHL and PBRM1 were the most frequently mutated genes. Baseline ctDNA/utDNA were analyzed in 51 RCC patients, with 18% (13% plasma, 12% urine) positivity in RCC and 19% (12% plasma, 12% urine) in ccRCC. During ccRCC monitoring, ctDNA/utDNA was positive only in M1 and M3, with 9% (9% plasma, 0% urine) and 18% (12% plasma, 6% urine), respectively. ctDNA-positive baseline plasma was associated to disease progression (p=0.0155) and tumor staging ≥pT3 (p=0.002); these patients also experienced reduced progression-free (p=0.004) and overall (p98%, resembling the patient’s tumor aggressiveness. Conclusions: ccRCC tumors release low levels of tumor DNA in urine and plasma. Pre-surgery plasma positivity for ctDNA appears to indicate a higher risk of recurrence in ccRCC patients. The ctDNA release of PDX tumors replicated that observed in one ccRCC patient with aggressive disease. Citation Format: Ana Carolina Kerekes Miguez, Isabella Tanus Job e Meira, Stephania Martins Bezerra, Adriano de Oliveira Beserra, Walter Henriques da Costa, Tiago Goss dos Santos, Stenio de Cassio Zequi, Giovana Tardin Torrezan, Dirce Maria Carraro. Circulating tumor DNA (ctDNA) in plasma and urine of renal cell carcinoma patients with localized disease [abstract]. In: Proceedings of the AACR Special Conference: Liquid Biopsy: From Discovery to Clinical Implementation; 2024 Nov 13-16; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(21_Suppl):Abstract nr A052.

Abstract A028: Precise monitoring of osteosarcoma patients by noninvasive assessment of matrix metalloproteinases activities in plasma extracellular vesicles

Abstract Osteosarcoma (OS) is the most prevalent bone cancer in children, characterized by aggressive primary tumors and high metastatic potential. Current treatment protocols involve a combination of neoadjuvant chemotherapy, surgery, and adjuvant chemotherapy, tailored based on histological grade and metastatic risk. Identifying metastatic lesions through routine imaging significantly impacts treatment outcomes, highlighting the need for innovative diagnostic tools for timely monitoring. Noninvasive in vitro diagnostics, analyzing circulating tumor components like tumor-derived extracellular vesicles (EVs), would offer promise for monitoring treatment responses in pediatric sarcomas. Matrix metalloproteinases (MMPs) play a crucial role in tumor progression by degradation of the extracellular matrix; thus, recent research has focused on understanding their functional roles by profiling their proteolytic activities. Tumor EVs are crucial in transporting MMPs to facilitate invasion and metastasis, making them suitable surrogate for noninvasive profiling of MMP activities. Herein, we introduce an innovative OS EV MMP Activity Assay to assess MMP activities in OS patients noninvasively. This assay evaluates six different combinations of surface markers on OS EVs and OS-associated MMPs, generating a unique profile for each patient. Using a logistic regression model, an OS EV MMP Activity Score is generated from the most effective combinations. This Score has shown excellent performance in distinguishing between metastatic and localized OS. In a longitudinal study of six OS patients undergoing treatment, the Score strongly correlated with treatment response as measured by routine imaging. The assay represents a significant advancement in harnessing tumor EVs for diagnostics, providing a noninvasive, quantitative, and reliable approach to assess MMP activities in solid tumors. Citation Format: Junseok Lee, You-Ren Ji, Hyoyong Kim, Zhao Chen, Ryan Zhang, Diego Banuet, Yusef Mathkour, Kenny Vo, Steven Jonas, Yazhen Zhu, Hsian-Rong Tseng. Precise monitoring of osteosarcoma patients by noninvasive assessment of matrix metalloproteinases activities in plasma extracellular vesicles [abstract]. In: Proceedings of the AACR Special Conference: Liquid Biopsy: From Discovery to Clinical Implementation; 2024 Nov 13-16; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(21_Suppl):Abstract nr A028.

Brachyury Expression in Atypical Teratoid/Rhabdoid Tumor.

Atypical teratoid/rhabdoid tumor (AT/RT) is a rare, highly aggressive central nervous system tumor of childhood with variable morphologic features, which is characterized by alterations in SWI/SNF complex, such as SMARCB1/INI1 or SMARCA4/BRG1 loss. Poorly differentiated chordoma is the differential diagnosis, particularly in the infratentorial region of older children and the use of brachyury in such conditions is under debate. We investigated the brachyury expression in 44 samples of AT/RT from 40 patients. All AT/RTs except 2 infratentorial tumors were negative for brachyury (2 clones: A-4 and EPR18113). Both brachyury-positive tumors (one diffuse and one patchy expression) involved the clivus of children younger than 2 years old. The DNA methylation profile of one of these tumors showed epigenetic similarity to reference examples of chordoma in 2 public unsupervised and one supervised analysis systems. The second tumor exhibited a classical epigenetic microarray pattern found in samples with degraded DNA. We revised 2 initial AT/RT diagnoses as poorly differentiated chordoma based on the morphology, brachyury expression, topographical features, and methylation profile. Differentiating poorly differentiated chordoma from AT/RT could be challenging; brachyury expression can be useful in diagnosing poorly differentiated chordoma over AT/RT in suitable clinical and radiological settings.

CAR-engineered NK cells versus CAR T cells in treatment of glioblastoma; strength and flaws.

Glioblastoma (GBM) is a highly aggressive primary brain tumor that carries a grim prognosis. Because of the dearth of treatment options available for treatment of GBM, Chimeric Antigen Receptor (CAR)-engineered T cell and Natural Killer (NK) therapy could provide alternative strategies to address the challenges in GBM treatment. In these approaches, CAR T and NK cells are engineered for cancer-specific immunotherapy by recognizing surface antigens independently of major histocompatibility complex (MHC) molecules. However, the efficacy of CAR T cells is hindered by GBM's downregulation of its targeted antigens. CAR NK cells face similar challenges, but, in contrast, they offer advantages as off-the-shelf allogeneic products, devoid of graft-versus-host disease (GVHD) risk as well as anti-cancer activity beyond CAR specificity, potentially reducing the risk of relapse or resistance. Despite CAR T cell therapies being extensively studied in clinical settings, the use of CAR-modified NK cells in GBM treatment remains largely in the preclinical stage. This review aims to discuss recent advancements in NK cell and CAR T cell therapies for GBM, including methods for introducing CARs into both NK cells and T cells, addressing manufacturing challenges, and providing evidence supporting the efficacy of these approaches from preclinical and early-phase clinical studies. The comprehensive evaluation of CAR-engineered NK cells and CAR T cells seeks to identify the optimal therapeutic approach for GBM, contributing to the development of effective immunotherapies for this devastating disease.