Stromal Tumors Research Articles

Targeting breast tumor extracellular matrix and stroma utilizing nanoparticles.

Breast cancer is a complicated malignancy and is known as the most common cancer in women. Considerable experiments have been devoted to explore the basic impacts of the tumor stroma, particularly the extracellular matrix (ECM) and stromal components, on tumor growth and resistance to treatment. ECM is made up of an intricate system of proteins, glycosaminoglycans, and proteoglycans, and maintains structural support and controls key signaling pathways involved in breast tumors. ECM can block different drugs such as chemotherapy and immunotherapy drugs from entering the tumor stroma. Furthermore, the stromal elements, such as cancer-associated fibroblasts (CAFs), immune cells, and blood vessels, have crucial impacts on tumor development and therapeutic resistance. Recently, promising outcomes have been achieved in using nanotechnology for delivering drugs to tumor stroma and crossing ECM in breast malignancies. Nanoparticles have various benefits for targeting the breast tumor stroma, such as improved permeability and retention, extended circulation time, and the ability to actively target the area. This review covers the latest developments in nanoparticle therapies that focus on breast tumor ECM and stroma. We will explore different approaches using nanoparticles to target the delivery of anticancer drugs like chemotherapy, small molecule drugs, various antitumor products, and other specific synthetic therapeutic agents to the breast tumor stroma. Furthermore, we will investigate the utilization of nanoparticles in altering the stromal elements, such as reprogramming CAFs and immune cells, and also remodeling ECM.

Heterogeneity of the Alpha-Smooth Muscle Actin Tumor Score in Breast Cancer Cells Significantly Affects Tumor Invasiveness, Recurrence, and Patient Survival.

Alpha-smooth muscle actin (αSMA) has been widely investigated in malignancies, primarily concerning its expression in cancer-associated fibroblasts (CAFs) inside the tumor stroma. Microscopic examination indicates that αSMA expression is not confined to the tumor stromal compartment but is also present in a subset of tumor cells, and this expression correlates with an enhanced invasive phenotype of malignant cells from lung, liver, or ovarian malignancies. Information on actin expression in breast cancer (BC) cells is scarce, and its influence on clinicopathological characteristics remains ambiguous due to conflicting findings in the literature. To examine the αSMA tumor score in breast cancer cells utilizing digital image analysis (DIA) methodologies and to critically analyze the varying effects of αSMA tumor score values on clinicopathologic parameters, particularly focusing on tumor cell invasiveness, recurrence, and survival. Double immunostaining for CD34 and αSMA was conducted on 53 breast cancer cases that were thoroughly characterized in relation to clinicopathologic data. Double immunostaining for CD34 and αSMA demonstrated different distribution patterns of both markers in normal and breast cancer tissues. DIAdata about αSMA tumor cell density, intensity, tumor score, and histological score were correlated with clinicopathological factors. We delineated three unique breast cancer subgroups based on αSMA tumor scores: a 9.43% low-expressing subgroup (αSMA_TSlow, score 4), a 35.07% medium-expressing subgroup (αSMA_TSmed, scores 5 and 6), and a 55.5% high-expressing subgroup (αSMA_TShigh, scores 7 and 8). Stromal immature vessels and tertiary lymphoid structures (TLS) exhibited a strong correlation with αSMA_TSlow, whereas recurrence, perineural, and lymphovascular invasion strongly influenced the αSMA_TSmed and αSMA_TShigh subgroups. The αSMA_TSmed subgroup demonstrated the most heterogeneity with the influence of αSMA-expressing breast cancer cells on tumor size, nodal status, perineural and lymphovascular invasion, menopausal status, recurrence, and survival. Most of the cases from the αSMA_TSlow subgroup had Luminal B and Luminal B-HER2 phenotypes, while triple-negative breast cancer (TNBC) represented one-third of all cases in the αSMA_TShigh subgroup. αSMA-expressing breast cancer cells variably affect malignant growth, invasion, and recurrence, highly contingent upon their density and expression intensity. The current investigation identified an αSMA_TSmed BC subgroup that appears to promote invasiveness, recurrence, and survival in breast cancer. Our data indicate that αSMA BC-expressing cells play a dual role in BC progression, contingent upon their percentage and expression intensity; however, further research is required to elucidate the factors and mechanisms responsible for their accumulation and/or transdifferentiation in malignant breast tissue.

Pathological features of the differentiation landscape in esophageal squamous cell cancer and their correlations with prognosis

BackgroundFor esophageal squamous cell carcinoma (ESCC), universally accepted pathological criteria for classification by differentiation degree are lacking. Tumor budding, single-cell invasion, and nuclear grade, recognized as prognostic factors in other carcinomas, have rarely been investigated for their correlation with differentiation and prognosis in ESCC. This study aims to determine if pathological findings can predict differentiation degree and prognosis in ESCC.Patients and methodsThis study reviewed tumor slides from 326 patients who underwent surgery for ESCC between 2007 and 2012. Tumors were evaluated for subtypes, tumor nest size, tumor stroma, and nuclear grade (nuclear diameter and mitosis) across different differentiation groups. Overall survival (OS) and disease-free survival (DFS) were estimated using the Kaplan-Meier method, with group differences assessed using the stratified log-rank test and Cox proportional hazards model.ResultsThe mean values of tumor budding invasion margins in well, moderately, and poorly differentiated groups were 25.3%, 30.7%, and 36.3%, respectively. Mean tumor budding/10HPFs were 8.0, 10.3, and 13.0, respectively. Well-differentiated tumors showed more keratinizing subtypes, smaller tumor budding invasion margins, more Grade 1 tumor budding (0-4 cells), absence of single-cell invasion, larger nuclear diameter (≥5 lymphocytes), higher mitotic counts, more submucosal invasion, and less lymphovascular invasion. Conversely, poorly differentiated tumors exhibited opposite characteristics. Multivariate analyses identified the nuclear diameter as independent prognostic factors for OS and DFS.ConclusionsPathological features can stratify the differentiation landscape in ESCC patients. The nuclear diameter (4 lymphocytes) can help predict prognosis in ESCC than other pathological features.Implications for practiceWe first time report the mean values of tumor budding invasion margins and tumor budding/10HPF in well, moderately, and poorly differentiated groups for esophageal squamous cell carcinoma. The landscape of well differentiation was depicted with more keratinizing subtypes, smaller tumor budding invasion margins, more Grade 1 tumor budding (0-4 cells), absence of single-cell invasion, larger nuclear diameter (≥5 lymphocytes), higher mitotic counts, and less lymphovascular invasion. The nuclear diameter as independent prognostic factors for prognosis. The findings indicate that pathological features can stratify the differentiation landscape in ESCC patients and offer novel insight into definition of well or moderately differentiation.

Macropinocytosis controls metabolic stress-driven CAF subtype identity in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) tumors are deficient in glutamine, an amino acid that tumor cells and CAFs use to sustain their fitness. In PDAC, both cell types stimulate macropinocytosis as an adaptive response to glutamine depletion. CAFs play a critical role in sculpting the tumor microenvironment, yet how adaptations to metabolic stress impact the stromal architecture remains elusive. In this study, we find that macropinocytosis functions to control CAF subtype identity when glutamine is limiting. Our data demonstrate that metabolic stress leads to an intrinsic inflammatory CAF (iCAF) program driven by MEK/ERK signaling. Utilizing in vivo models, we find that blocking macropinocytosis alters CAF subtypes and reorganizes the tumor stroma. Importantly, these changes in stromal architecture can be exploited to sensitize PDAC to immunotherapy and chemotherapy. Our findings demonstrate that metabolic stress plays a role in shaping the tumor microenvironment, and that this attribute can be harnessed for therapeutic impact.

MRI analysis of relative tumor enhancement in liver metastases and correlation with immunohistochemical features

ObjectiveInvestigate the association between the relative tumor enhancement (RTE) of gadoxetic acid across various MRI phases and immunohistochemical (IHC) features in patients with liver metastases (LM) from colorectal cancer (CRC), breast cancer (BC), and pancreatic cancer (PC).MethodsA retrospective analysis was conducted on 68 patients with LM who underwent 1.5-T MRI scans. Non-contrast and contrast-enhanced T1-weighted (T1-w) gradient echo (GRE) sequences were acquired before LM biopsy. RTE values among LM groups were compared by cancer type using analysis of variance. The relationships between RTE and IHC features tumor stroma ratio, cell count, Ki67 proliferation index, and CD45 expression were evaluated using Spearman’s rank correlation coefficients.ResultsSignificant differences in RTE were observed across different MRI phases among patients with BCLM, CRCLM, and PCLM: arterial phase (0.75 ± 0.42, 0.37 ± 0.36, and 0.44 ± 0.19), portal venous phase (1.09 ± 0.41, 0.59 ± 0.44, and 0.53 ± 0.24), and venous phase (1.11 ± 0.45, 0.65 ± 0.61, and 0.50 ± 0.20). In CRCLM, RTE inversely correlated with mean Ki67 (r = −0.50, p = 0.01) in the hepatobiliary phase. Negative correlations between RTE and CD45 expression were found in PCLM and CRCLM in the portal venous phase (r = −0.69, p = 0.01 and r = −0.41, p = 0.04) and the venous phase (r = −0.65, p = 0.01 and r = −0.44, p = 0.02).ConclusionSignificant variations in RTE were identified among different types of LM, with correlations between RTE values and IHC markers such as CD45 and Ki67 suggesting that RTE may serve as a non-invasive biomarker for predicting IHC features in LM.Critical relevance statementRTE values serve as a predictive biomarker for IHC features in liver metastasis, potentially enhancing non-invasive patient assessment, disease monitoring, and treatment planning.Key PointsFew studies link gadoxetic acid-enhanced MRI with immunohistochemistry in LM.RTE varies by liver metastasis type and correlates with CD45 and Ki67.RTE reflects IHC features in LM, aiding non-invasive assessment.Graphical

A novel small molecule Enpp1 inhibitor improves tumor control following radiation therapy by targeting stromal Enpp1 expression

The uniqueness in each person’s cancer cells and variation in immune infiltrates means that each tumor represents a unique problem, but therapeutic targets can be found among their shared features. Radiation therapy alters the interaction between the cancer cells and the stroma through release of innate adjuvants. The extranuclear DNA that can result from radiation damage of cells can result in production of the second messenger cyclic guanosine monophosphate–adenosine monophosphate (cGAMP) by cyclic GMP-AMP synthase (cGAS). In turn, cGAMP can activate the innate sensor stimulator of interferon genes (STING), resulting in innate immune activation. Ectonucleotide pyrophosphatase/phosphodiesterase 1 (Enpp1) is a phosphodiesterase that can be expressed by cancer cells that can degrade cGAMP, thus can decrease or block STING activation following radiation therapy, impairing the innate immunity that is critical to support adaptive immune control of tumors. We observed that many human and murine cancer cells lack Enpp1 expression, but that Enpp1 is expressed in cells of the tumor stroma where it limits tumor control by radiation therapy. We demonstrate in preclinical models the efficacy of a novel Enpp1 inhibitor and show that this inhibitor improves tumor control by radiation even where the cancer cells lack Enpp1. This mechanism requires STING and type I interferon (IFN) receptor expression by non-cancer cells and is dependent on CD8 T cells as a final effector mechanism of tumor control. This suggests that Enpp1 inhibition may be an effective partner for radiation therapy regardless of whether cancer cells express Enpp1. This broadens the potential patient base for whom Enpp1 inhibitors can be applied to improve innate immune responses following radiation therapy.

Multiomics reveals tumor microenvironment remodeling in locally advanced gastric and gastroesophageal junction cancer following neoadjuvant immunotherapy and chemotherapy

BackgroundPerioperative chemotherapy is the standard of care for patients with locally advanced gastric and gastroesophageal junction cancer. Recent evidence demonstrated the addition of programmed cell death protein 1 (PD-1) inhibitors...

Tissue Expression and Plasma Soluble PD-L1 Levels in Patients With Endometrial Cancer.

The prognostic role of tissue PD-L1 expression in endometrial cancer (EC) remains controversial. Moreover, its value in guiding anti-PD1/PD-L1 immunotherapy is questionable. The eventual role of soluble PD-L1 (sPD-L1), released by cancer tissue and circulating immune cells, is largely unexplored. In this pilot study, we investigated the expression of PD-L1 in cancer cells and tumor stroma infiltrating inflammatory cells (TIICs), in parallel with sPD-L1 levels in the plasma of 19 patients with early-stage endometrioid EC, before and after hysterectomy. Cancer cell membrane staining was noted in 5/19 (26.3%) cases (range=1-5%; median 1% of the cancer cell population). IICs showed positive reactivity in 14/19 (73.7%) cases. sPD-L1 plasma levels ranged from 53-408 pg/ml and 113-557 pg/ml, respectively, in the plasma of patients before and after hysterectomy (p=0.01). High PD-L1 expression by IIC was marginally associated with a high histology grade (p=0.08). High sPD-L1 levels before surgery were significantly associated with ICC PD-L1 expression (p=0.0007), high histology grade (p=0.04), and marginally with T2-stage (p=0.08). sPD-L1 is easily detectable in the plasma of EC patients and may be associated with aggressive clinical features and PD-L1-expressing immune cells infiltrating the tumor stroma. sPD-L1 plasma levels in EC patients undergoing immunotherapy can be further tested as a biomarker for therapeutic stratification.

Challenges and Opportunities in Targeting the Complex Pancreatic Tumor Microenvironment

Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer-related deaths with a 5-year survival rate of 13%. Surgical resection remains the only curative option as systemic therapies offer limited benefit. Poor response to chemotherapy and immunotherapy is due, in part, to the dense stroma and heterogeneous tumor microenvironment (TME). Opportunities to target the PDAC stroma may increase the effectiveness of existing or novel therapies. Current strategies targeting the stromal compartment within the PDAC TME primarily focus on degrading extracellular matrix or inhibiting stromal cell activity, angiogenesis, or hypoxic responses. In addition, extensive work has attempted to use immune targeting strategies to improve clinical outcomes. Preclinically, these strategies show promise, especially with the ability to alter the tumor ecosystem; however, when translated to the clinic, most of these trials have failed to improve overall patient outcomes. In this review, we catalog the heterogenous elements of the TME and discuss the potential of combination therapies that target the heterogeneity observed in the TME between patients and how molecular stratification could improve responses to targeted and combination therapies.

Recent advances in nuclear medicine and their role in inflammatory arthritis: focus on the emerging role of FAPI PET/CT

AbstractImaging molecular processes associated with inflammatory disease has been revolutionized by hybrid imaging using positron emission tomography/computed tomography (PET/CT). PET/CT visualizes metabolic activity as well as protein expression and provides a comprehensive whole-body evaluation. It has the potential to reveal inflammation prior to detection of structural changes in inflammatory joint diseases. FAP is a type II transmembrane glycoprotein overexpressed not only in the stroma of tumors but also in the fibrotic processes of certain immune-mediated disorders. The recent introduction of fibroblast activation protein inhibitors (FAPI) labeled by positron emitters and thus suitable for PET/CT allows to investigate FAP expression in vivo. This review will focus on the use of FAPI-PET/CT for the diagnosis and evaluation of treatment response in inflammatory joint diseases.

Comparative evaluation of collagen modifications in breast cancer in human and canine carcinomas

New diagnostic and therapeutic approaches have been increasingly demanded due to the high morbidity and mortality associated with breast cancer. Recently, changes in the collagen fibres in mammary neoplasms have been shown to provide information that can be helpful for more accurate diagnosis. We aimed to conduct a comparative analysis of the tumour stroma in human and canine mammary neoplasms to assess the relationship between collagen modifications and the behaviour of carcinomas in both species, by multiphoton microscopy. We present a retrospective study of 70 cases of human mammary tumour and 74 cases of canine mammary tumour. We analysed sections stained with haematoxylin and eosin from 1,200 representative areas of normal mammary tissue, fibroadenoma, grade I invasive carcinoma, grade III invasive carcinoma and invasive micropapillary carcinoma in human species and 1,304 representative areas of normal mammary tissue, benign mixed tumour, mixed carcinoma, carcinosarcoma, invasive micropapillary carcinoma and solid carcinoma in canine species. We obtained that both human and canine mammary carcinomas present lower density of collagen fibres, higher density of cells and the collagen fibres are more aligned than in normal tissue. For human mammary carcinomas, the collagen fibres are more linear as compared to normal tissue. In addition, we demonstrated that the carcinomas with unfavourable prognosis present shorter collagen fibres, and these collagen changes correlate with the clinical and pathological data in human and canine species. For dogs, there is a correlation between the mean fibre length with the specific survival times. Thus, we demonstrate that dogs provide an excellent comparative perspective for studying how changes in the tumour stroma affect patient survival.

EGCG-enabled Deep Tumor Penetration of Phosphatase and Acidity Dual-responsive Nanotherapeutics for Combinatory Therapy of Breast Cancer.

The presence of dense collagen fibers is a typical characteristic of triple-negative breast cancer (TNBC). Although these fibers hinder drug penetration and reduce treatment efficacy, the depletion of the collagen matrix is associated with tumor metastasis. To address this issue, epigallocatechin-3-gallate (EGCG) is first exploited for disrupting the dense collagenous stroma and alleviate fibrosis by specifically blocking the TGF-β/Smad pathway in fibroblasts and tumor cells when intraperitoneally administrated in TNBC tumor-bearing mice. A methotrexate (MTX)-loaded dual phosphate- and pH-responsive nanodrug (pHA@MOF-Au/MTX) is next engineered by integrating Fe-based metal-organic frameworks and gold nanoparticles for improved chemo/chemodynamic therapy of TNBC. Surface modification with pH (low)-insertion peptide substantially enhanced the binding of the nanodrug to 4T1 cells owing to tumor stroma remodeling by EGCG. High-concentration EGCG inhibited glutathione peroxidase by regulating mitochondrial glutamine metabolism, thus facilitating tumor cell ferroptosis. Furthermore, sequential EGCG and pHA@MOF-Au/MTX treatment showed remarkable anti-tumor effects in a mouse model of TNBC, with a tumor growth inhibition rate of 79.9%, and a pulmonary metastasis rate of 96.8%. Altogether, the combination strategy developed in this study can improve the efficacy of chemo/chemodynamic therapy in TNBC and represents an innovative application of EGCG.

Quantitative distribution of essential elements and non-essential metals in breast cancer tissues by LA-ICP-TOF-MS.

Breast cancer (BC) is the leading cause of cancer death among women worldwide, making the discovery and quantification of new biomarkers essential for improving diagnostic and preventive strategies to limit dissemination and improve prognosis. Essential trace metals such as Fe, Cu, and Zn may play critical roles in the pathophysiology of both benign and malignant breast tumors. However, due to the high metabolic activity and reduced element selectivity of cancer cells, also non-essential elements may be taken up and may even be implicated with disease progression. This study investigates the spatial distribution and concentrations of both essential and non-essential elements in breast tissues, assessing their potential for diagnostic applications. Laser ablation (LA)-inductively coupled plasma-mass spectrometry (ICP-MS) with a time-of-flight (ToF) mass analyzer (LA-ICP-ToF-MS) was used to inquire the distribution of almost all elements across the periodic table and their abundance in metastatic (n = 11), non-metastatic (n = 7), and healthy (n = 4) breast tissues. Quantification was achieved using gelatine-based standards for external calibration to quantitatively map various elements. Overall, the Fe, Cu, Zn, Sr, and Ba levels were significantly increased in tumor samples with Sr and Ba showing strong correlation, likely due to their similar chemistry. Comparison of calibrated LA-ICP-ToF-MS data with a histologic staining demonstrated the possibility to clearly differentiate between varioustissue types and structures in breast tissues such as tumor niche and stroma. The levels of thestudied elements were significantly higher inthe tumor niche areas compared to the stroma, and for Fe, a significant accumulation was observed in the tumor niche areas from the metastatic patient group relative to the levels found in the same areas of the non-metastatic group.

Abstract A041: Deciphering the crosstalk between cancer cells and stroma that drives EMT- coupled fibrosis

Abstract In the tumor microenvironment (TME) cancer cells engage dynamically with the stromal component in promoting tumor progression and metastasis formation that are accompanied by intratumor fibrosis. Extensive extracellular matrix (ECM) remodeling and stiffness boost fibrosis which co-occurs with poor immune infiltration. Very little is known about the cross-interactions between tumor cells and stroma. A better understanding of this dynamic relationship may advance the development of new therapies. Transforming growth factor (TGF)-β signaling in both cancer epithelial cells and stroma is crucial for the establishment of intratumor fibrosis that enhances tumor progression. We previously discovered that in cancer cells, TGF-β signaling synergizes with RAS signal to regulate classical EMT transcription factors (Snail, Zeb1) and fibrogenic factors (Il11, Pdgf, Ctgfb, Wisp and others). This synergistic program is required for metastasis formation in pancreatic and lung adenocarcinoma (LUAD) models. However, how this dual program is affecting the stromal population in vivo remains unknown. Additionally, the role of each TGF-β dependent fibrogenic factor in regulating the stroma is still unclear. Using metastasis in vivo assays, we tested the metastatic ability of LUAD cells wild-type in comparison to Knock-Out cells targeting each one of the TGF-β dependent fibrogenic factors. We found that these factors are drivers of metastasis. More interestingly, these fibrogenic factors have a preferential effect depending on the metastatic site, suggesting that survival of the cancer cells in a certain tissue is dependent on the stromal niche within the site, which will act in favor or not of their growth. We also deeply characterize the stroma of micro-metastatic lesions by using high-throughput multiplex immunofluorescence to analyze the whole tissue TME at single cell resolution and found that lack of any of these fibrogenic factors compromise the establishment of a robust ECM at the very beginning of the metastatic colonization, to favor immune infiltration and consequently lead to cancer cell clearance. Together, these findings shed light on the potential role of these specific fibrogenic factors in metastasis, how their absence impacts the TME and how targeting these factors could be beneficial in metastatic disease. Citation Format: Elena Spina, Liangji Li, Junho Lee, Joan Massaguè. Deciphering the crosstalk between cancer cells and stroma that drives EMT- coupled fibrosis [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 A041.

Abstract A035: Infection of primary mammary fibroblasts with cytomegalovirus coordinately increases autotaxin-lysophosphatidate-inflammatory signaling, which could increase breast cancer metastasis

Abstract Background: Metastatic breast cancer is the most prevalent cause of mortality by cancer-related deaths in women. Our group showed that the 63% of Canadian breast cancer patients who were infected with CMV were 5.6-times more likely to develop Stage IV cancers with reduced relapse-free survival. Also, the metastatic phenotype of breast tumors and the number and sizes of lung metastases were increased in mice with latent infections. Fibroblasts are important sites of CMV infection. Cancer-associated fibroblasts (CAFs) are also major sites of autotaxin (ATX) secretion in breast tumors, whereas ATX production and CMV infection in breast cancer cells is negligible. ATX produces lysophosphatidate (LPA), which increases inflammatory cytokine production that stimulates further ATX secretion in a feedforward cycle. LPA promotes breast tumor growth and metastasis by signaling through six G protein-coupled receptors. Signaling is terminated by lipid phosphate phosphatases (LPPs)-1 and -3, which degrade LPA and are decreased in breast tumors. Hypothesis: Breast cancer metastasis could be increased by active CMV infection of CAFs through increased inflammation and LPA signaling. Results: Quiescent fibroblasts isolated and cultured from mammary tissue of non-tumor bearing mice (n>3) produced negligible quantities of ATX. LPA signaling was coordinately promoted in these primary fibroblasts infected for 48 h with 1 MOI of mouse CMV (n=3) with a 5-fold increase in mRNA for ATX (p=0.008), increased mRNAs for LPA2,3,4 receptors (p<0.05) and decreased mRNA expressions for LPP1 and LPP3 (p<0.05). An increase in the secretion of granulocyte monocyte-colony stimulating factor of 548 pg/ml (p=0.01) and Interleukin-6 by 8307 pg/ml (p=0.03) was observed post infection (n=5), thus creating a pro-inflammatory environment. Increased mRNA expression of fibroblast markers, including alpha-smooth muscle actin (p=0.005), fibroblast-associated protein (p=0.007), epidermal growth factor receptor (EGFR) (p=0.001) and transforming growth factor- ß receptor 1 (TGF-ßR1) (p=0.03) was also observed post-infection (n=3). The results were analyzed by student’s t-test. Assessment of these factors in breast cancer patients (n=1100) using the Tumor Immune Estimation Resource Analysis showed a positive correlation in the expression of EGFR and TGF-ßR1 with the LPA3,4 receptors (p<0.05). Conclusion: The changes in expression of ATX, LPA receptors and LPPs in CMV- infected fibroblasts are consistent with increased metastasis. Our results show that mCMV infection of primary mammary fibroblasts dramatically reprograms them to express CAF-like properties and promotes ATX-LPA-inflammatory signaling. CAFs are a major constituent of the tumor stroma. They promote tumor progression by secreting factors such as ATX, which increases metastasis, fibrosis and favors immunosuppression. Our results support the use of pharmacological agents to block signaling by the ATX-LPA-inflammatory cycle to treat breast and other cancers, especially for the majority of patients who are infected with CMV. Citation Format: Humayara Khan, Xiaoyun Tang, Frank Wuest, David N. Brindley, Denise G. Hemmings. Infection of primary mammary fibroblasts with cytomegalovirus coordinately increases autotaxin-lysophosphatidate-inflammatory signaling, which could increase breast cancer metastasis [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 A035.

The diagnostic value of endoscopic ultrasound for esophageal subepithelial lesions: A review.

Esophageal subepithelial lesions (ESELs) encompass a variety of diseases, including leiomyoma, granular cell tumors, hemangioma, lipoma, stromal tumors, leiomyosarcoma, schwannoma, neuroendocrine tumors and more. These lesions often present asymptomatically, leading to a generally low clinical diagnosis rate. Common imaging techniques for diagnosing ESELs include conventional endoscopy, spiral computed tomography, and endoscopic ultrasound (EUS). Among these, EUS is currently regarded as one of the most accurate methods for diagnosing ESELs. In recent years, EUS has increasingly been combined with advanced technologies such as artificial intelligence, submucosal saline injection, high-frequency impedance measurement, and enhanced imaging to improve diagnostic accuracy and reduce missed diagnoses. This article reviews the application and recent advancements of EUS in diagnosing esophageal submucosal lesions.

Aberrant expression of collagen type X in solid tumor stroma is associated with EMT, immunosuppressive and pro-metastatic pathways, bone marrow stromal cell signatures, and poor survival prognosis.

Collagen type X (ColXα1, encoded by COL10A1 ) is expressed specifically in the cartilage-to-bone transition, in bone marrow cells, and in osteoarthritic (OA) cartilage. We have previously shown that ColXα1 is expressed in breast tumor stroma, correlates with tumor-infiltrating lymphocytes, and predicts poor adjuvant therapy outcomes in ER + /HER2 + breast cancer. However, the underlying molecular mechanisms for these effects are unknown. In this study, we performed bioinformatic analysis of COL10A1 -associated gene modules in breast and pancreatic cancer as well as in cells from bone marrow and OA cartilage. These findings provide important insights into the mechanisms of transcriptional and extracellular matrix changes which impact the local stromal microenvironment and tumor progression. Immunohistochemistry was performed to examine collagen type X expression in solid tumors. WGCNA was used to generate COL10A1 -associated gene networks in breast and pancreatic tumor cohorts using RNA-Seq data from The Cancer Genome Atlas. Computational analysis was employed to assess the impact of these gene networks on development and progression of cancer and OA. Data processing and statistical analysis was performed using R and various publicly-available computational tools. Expression of COL10A1 and its associated gene networks highlights inflammatory and immunosuppressive microenvironments, which identify aggressive breast and pancreatic tumors and contribute to metastatic potential in a sex-dependent manner. Both cancer types are enriched in stroma, and COL10A1 implicates bone marrow-derived fibroblasts as drivers of the epithelial-to-mesenchymal transition (EMT) in these tumors. Heightened expression of COL10A1 and its associated gene networks is correlated with poorer patient outcomes in both breast and pancreatic cancer. Common transcriptional changes and chondrogenic activity are shared between cancer and OA cartilage, suggesting that similar microenvironmental alterations may underlie both diseases. COL10A1 -associated gene networks may hold substantial value as regulators and biomarkers of aggressive tumor phenotypes with implications for therapy development and clinical outcomes. Identification of tumors which exhibit high expression of COL10A1 and its associated genes may reveal the presence of bone marrow-derived stromal microenvironments with heightened EMT capacity and metastatic potential. Our analysis may enable more effective risk assessment and more precise treatment of patients with breast and pancreatic cancer. ColX highlights features of EMT in breast and pancreatic cancerColX gene modules are immunosuppressive and pro-metastaticColX-associated gene networks contribute to sex differences in pancreatic cancerColX-positive fibroblasts define more aggressive tumors with poorer survivalColX is emerging as a biomarker for bone marrow-derived cells in cancer.

Gastric glomus tumor with uncertain malignant potential: case report of a rare cause of upper gastrointestinal bleeding

BackgroundGlomus tumors (GTs) are mesenchymal neoplasms that are typically benign. Gastric GTs are uncommon and occur mainly in the upper gastrointestinal tract. Malignant gastric GTs are extremely rare, constituting less than 1% of gastric tumors. Because their features are similar to those of other tumors found in the same gastrointestinal region, such as stromal tumors, leiomyomas, lymphomas, and lipomas, the diagnosis is challenging.Case PresentationA 52-year-old male patient presented with fatigue and melena. The initial endoscopic examination did not locate any source of bleeding. Six months later, pan-gastroscopy, performed due to progressive microcytic anemia, revealed a 40 × 30 mm polypoid lesion with deep ulcerations; histopathological analysis confirmed that it was a gastric GT with expression of alpha-actin and cadherin 17 and a Ki-67 index of 20%. The patient delayed surgical therapy until his symptoms worsened. Laparoscopic sleeve resection revealed a 65 × 45 × 25 mm tumor, and secondary immunohistochemical analysis revealed extensive spread into the mucosa and subserosa. Focally, the tumor bulged into some large veins. Genetic examination with RNA isolation further supported the histopathological diagnosis of gastric GT with uncertain malignant potential.ConclusionsThis case underscores the diagnostic challenges posed by gastric GTs because they are rare and their clinical features are similar to those of other gastric tumors. Thorough histopathological and molecular analysis is essential for an accurate diagnosis. Surgical intervention remains the primary therapeutic approach. This case also emphasizes the need for long-term follow-up due to the potential for recurrence and malignancy.

EXTH-48. ADENO-ASSOCIATED VIRUS TARGETING OF THE TUMOR MICROENVIRONMENT TO IMPROVE LYMPHOCYTE RECRUITMENT IN GLIOBLASTOMA

Abstract BACKGROUND Glioblastoma (GBM) is notoriously devoid of lymphocytes driven in part by a paucity of lymphocyte trafficking factors necessary to prompt their recruitment, infiltration, and activation. We have developed a novel recombinant adeno-associated virus (AAV) gene therapy strategy that enables focal and stable reconstitution of the GBM tumor microenvironment (TME) with C-X-C motif ligand 9 (CXCL9), a powerful call-and-receive chemokine for cytotoxic T lymphocytes (CTLs). By increasing lymphocyte recruitment in GBM, we HYPOTHESIZE that these tumors will be more responsive to immunotherapy. METHODS 3D fluorescence microscopy was used to characterize the distribution, tropism, and durability of AAV6 transgene expression in preclinical GBM. Flow cytometry and 3D fluorescence microscopy was used to quantify T cell infiltration and visualize their biodistribution in preclinical GBM treated with AAV-CXCL9 in combination with anti-PD-1 immune checkpoint blockade (ICB). Single-cell RNA sequencing was used to characterize intratumor lymphocyte subsets following treatment. Survival studies with and without lymphocyte depletion were done to evaluate immunogenic responsiveness of therapy. RESULTS Focal delivery of CXCL9 with AAV6 results in stable transduction of peri-tumoral astrocytes. When combined with anti-PD-1 ICB, lymphocyte infiltration was improved, with cells found disseminated across the tumor stroma and within the tumor parenchyma. CXCR3, the chemokine receptor for CXCL9, was expressed across lymphocyte subsets and NKT cells, validating treatment selectivity of AAV6-CXCL9 for lymphocytes. Combination treatment considerably improved overall survival in two distinct GBM models, with durable responses dependent on CD8 T-lymphocyte infiltration. CONCLUSIONS By manipulating local chemokine directional guidance, AAV-CXCL9 increases tumor infiltration by CD8-postive cytotoxic lymphocytes, sensitizing GBM to anti-PD-1 ICB. These effects are accompanied by immunologic signatures evocative of an inflamed and responsive TME. These findings support targeted AAV gene therapy as a promising adjuvant strategy for reconditioning GBM immunogenicity given its excellent safety profile, TME-tropism, modularity, and off-the-shelf capability.

TMIC-37. GEMISTOCYTIC TUMOR CELLS AND IMMUNE REACTIVE MICROGLIA PROGRAMMED FOR GLIAL SCARRING CHARACTERIZE T CELL CONTAINMENT IN IDH-MUTANT ASTROCYTOMA

Abstract Isocitrate dehydrogenase 1/2 mutant (IDHmt) astrocytoma is considered a T cell-deprived tumor, yet little is known regarding the phenotype that relates to T cell exclusion. To aid better understanding of this mechanism, we systematically characterized the IDHmt astrocytoma immune microenvironment in a large cohort by multiplex immunofluorescence (IF) (n=75), bulk RNA sequencing (n=158), single nucleus RNA sequencing (n=7) and spatial RNA and protein profiling (n=12). We integrated and analyzed all datasets to acquire a robust characterization of the microenvironment organization and validated our results using IF stainings. We demonstrated that in IDHmt astrocytomas, T cells were contained in the perivascular space (i.e., T cell cuffs). In the tumor stroma surrounding T cell cuffs, we found a dense accumulation of gemistocytic tumor cells (GTCs), a histologically distinct tumor cell subtype. GTC-high tumors demonstrated enhanced expression of immune cell migration and activation pathways that were reliably expressed by TAMs and T cells. Notably, we found that GTCs formed a unique transcriptional cell sub-cluster that expressed markers including CD44, TNC and CRYAB, which are specific for glial scarring, a central nervous system specific mechanism for immune exclusion. Surrounding T cell cuffs, GTCs co-localized with immune-reactive microglia that expressed the chemoattractants CCL3 and CCL4. Together, co-localizing GTCs and reactive microglia expressed receptor-ligand pairs that take part in reactive astrogliosis and glial scarring, including Osteopontin – CD44 and IL-1β – IL1R1. Validation whole-slide multiplex IF stainings for this spatial relationship showed specific local accumulation of CD44 positive GTCs and TAMs around T cell cuffs in GTC-high tumors, which was absent in GTC-low tumors. Together, we show that IDHmt astrocytomas organize a network of tumor cells and leukocytes that mimics glial scarring and can aid T cell exclusion. Elucidating such specific immune exclusion mechanisms is vital for more appropriate target selection in novel immune therapies.