Journal for ImmunoTherapy of Cancer

Interleukin-2 (IL-2) remains an attractive cytokine for enhancing antigen-specific CD8 T cell responses in cancer immunotherapy, but systemic toxicity hinders its broad clinical application. To address this, various IL-2-based therapeutics have been engineered with altered IL-2 receptor bias or targeted delivery to tumors, the tumor microenvironment, or immune cell populations. Ideally, IL-2 signals should be selectively delivered to antigen-specific CD8 T cells, boosting their responses and promoting effector differentiation while sparing non-targeted populations. Immuno-STATTM (Selective Targeting and Alteration of T cells) is a fusion protein platform comprising a bivalent peptide-MHC class I complex and an affinity-attenuated IL-2 mutein that co-stimulates TCR and IL-2 signaling in epitope-specific CD8 T cells. Here, we investigated whether a DbGP33-41-targeted Immuno-STAT enhances DbGP33-specific CD8 T cell responses in a mouse model of chronic lymphocytic choriomeningitis virus (LCMV) infection. Immuno-STAT treatment selectively expanded DbGP33-specific CD8 T cells with an effector-like phenotype. Non-targeted DbGP276-specific CD8 T cells showed little to no expansion in response to DbGP33-41-targeted Immuno-STAT therapy, underscoring the selectivity of this approach. However, minor changes in phenotypic markers, including increased expression of CD25 and CX3CR1, were observed in non-targeted CD8 T cells, likely reflecting bystander IL-2 signaling. Combining Immuno-STAT with PD-1 blockade augmented DbGP33-specific CD8 T cell responses more effectively than PD-1 blockade alone, with minor effects on the non-targeted DbGP276-specific population. These findings inform the clinical development of Immuno-STAT and other IL-2 therapeutics and highlight the value of coordinated TCR and IL-2 stimulation during chronic antigen exposure, alone or in combination with PD-1 blockade. IMPORTANCEInterleukin-2 (IL-2) is a key cytokine for promoting effector differentiation of antigen-specific CD8 T cells and remains an attractive agent in cancer immunotherapy, but systemic toxicity limits its clinical use. This study addresses a central challenge in IL-2-based immunotherapy: delivering IL-2 to cognate antigen-specific CD8 T cells while minimizing activation of non-targeted populations. Using a mouse model of chronic lymphocytic choriomeningitis virus (LCMV) infection, we show that the Immuno-STAT (Selective Targeting and Alteration of T cells) platform selectively expands targeted virus-specific CD8 T cells and enhances their function while limiting effects on non-targeted populations. We also show that combining Immuno-STAT with PD-1 blockade further enhances targeted virus-specific CD8 T cell responses during chronic LCMV infection. These findings provide mechanistic and preclinical support for integrating T cell receptor (TCR) specificity with IL-2 signaling to advance cancer immunotherapy and guide next-generation IL-2 therapeutics for cancer and chronic infection.

PURPOSE: Newly-diagnosed glioblastoma (nGBM) is a devastating tumor with median survival of only 14-18 months despite aggressive standard of care (SOC). Dendritic cell (DC) homologous antigenic double-loading provides a powerful pattern-based signal that initiates cDC1-like skewing of monocytic precursors, inducing downstream development of CD8+ memory effectors. Here we report phase I results for DOC1021 (dubodencel), a novel DC vaccine regimen integrated with SOC. METHODS: In this dose-escalating study, DC prepared from mobilized peripheral blood were doubly loaded with autologous tumor lysate and amplified tumor mRNA and administered bilaterally near the deep cervical node chains in three biweekly courses given with weekly peg-IFN after conclusion of chemoradiation. Four dose levels from 3.5x106 to 3.6x107 total cells were tested. Patients with subtotal resection or tumor progression prior to vaccination were not excluded. RESULTS: Eighteen patients (median age 61 years (range 47-73), 94% MGMT unmethylated, 25% subtotal/partial resected) completed vaccination (16 nGBM, 2 recurrent) with no dose-limiting toxicities. Attributable AE were mostly mild and flu-like or injection-site reactions. Twelve-month OS among the newly-diagnosed cohort was 88% compared to an expected ~60% for SOC alone. Patients who received observation rather than reoperation in response to worsening MRI contrast-enhancement demonstrated gradual lesional resolution and improved OS. Immunophenotyping revealed post-vaccination elevations in CD4 and CD8 memory T-cells in peripheral blood, and spatial transcriptomic analysis revealed foci of activated inflammatory complexes at the primary tumor site. CONCLUSIONS: DOC1021 was safe, feasibly integrated within SOC, and associated with more favorable outcomes in this challenging patient population. Patients who received observation rather than reoperation for worsening MRI contrast-enhancement exhibited superior survival, suggesting an immune-reactive tumor microenvironment manifesting as pseudo-progression. These data supported initiation of a randomized Phase II trial (NCT06805305) for nGBM.

CAR-T immunotherapy has achieved remarkable efficacy in hematologic malignancies. However, the widespread clinical adoption of autologous CAR-T products remains constrained by high costs, lengthy manufacturing process, and limited accessibility. Universal or off the shelf CAR-T (UCAR-T) cells derived from healthy donors offer a promising alternative, enabling immediate treatment at a lower cost. However, the allogeneic nature of UCAR-T cells triggers immune rejection by the host immune system after infusion, thereby compromising their persistence and therapeutic efficacy. Current strategies to circumvent this rejection focus on disrupting HLA class I expression. Although this modification allows UCAR-T cells to successfully evade T cell mediated elimination, the loss of HLA class I molecules renders them vulnerable to attack by host natural killer (NK) cells. In contrast to previous approaches that attempt to retain certain non-classical HLA molecules (such as HLA-E or HLA-G) to inhibit NK cells, we directly focused on editing the ligands that mediate NK cell rejection. Through transcriptomic and in vitro validation analyses, we found that UL16 binding proteins (ULBP) 2/5/6 were substantially upregulated in UCAR-T cells compared with nontransduced donor T cells. Elevated ULBP expression effectively activates the NKG2D receptor on allogeneic NK cells and leads to killing of UCAR-T cells, thereby impairing UCAR-T function. To test whether abrogating this NK activating signal could improve UCAR-T persistence and antitumor efficacy, we generated ULBP knockout UCAR-T cells using CRISPR-Cas9 editing. Deletion of ULBP2/5/6 significantly reduced NK cell mediated killing in vitro without affecting CAR expression or T cell effector function. Compared with wild type UCAR-T cells, ULBP deficient UCAR-T cells exhibited enhanced tumor killing efficacy in the presence of NK cells. Collectively, our findings identify ULBP upregulation as one of the mechanisms underlying NK cell mediated rejection of HLA deficient UCAR-T cells. Targeted ablation of ULBP molecules provides a novel strategy to confer resistance to host NK cells, thereby improving the therapeutic potential of universal CAR T products.

In recent years, immunotherapy of patients with higher-risk non-muscle invasive bladder cancer (NMIBC) in North America has relied on the use of the TICE strain of BCG. However, limitations in the supply chain have warranted investigation of the therapeutic benefit of other strains of BCG, such as BCG-Russia. Trained immunity, a form of innate immune memory, is now widely believed to be an important component of the therapeutic benefit of BCG. Therefore, in the present study we compared the effects of BCG-TICE and BCG-Russia on the acquisition of trained immunity and related secondary immune responses. C57BL/6 mice received a single intravenous injection of BCG-Russia or BCG-TICE. Four weeks later, bone marrow was collected for flow cytometric analysis of hematopoietic stem and progenitor cell (HSPC) populations, generation of bone marrow-derived macrophages, functional assessment of trained immunity, and transcriptomic profiling. Compared with BCG-Russia, BCG-TICE elicited stronger levels of trained immunity, characterized by higher production of several proinflammatory cytokines upon secondary activation. BCG promoted the expansion of HSPCs independent of strain. BCG-TICE was linked to upregulation of key inflammation-related genes and enrichment of functionally relevant pathways. The results of this study reveal strain-dependent differences in the ability of BCG to induce innate immune memory and inflammatory pathways that could ultimately determine efficacy of immunotherapy of patients with NMIBC.

Cancer remains a major therapeutic challenge despite substantial advances in diagnosis and treatment, including immune checkpoint blockade. Among emerging immunotherapeutic approaches, adoptive cell transfer (ACT) has attracted growing interest. Human peripheral V{gamma}9V{delta}2 T cells are promising candidates for ACT because they combine rapid and potent antitumor functions with major histocompatibility complex (MHC)-independent tumor recognition, enabling allogeneic use with limited risk of graft-versus-host disease. This raises the possibility of generating standardized V{gamma}9V{delta}2 T-cell banks from healthy donors for off-the-shelf immunotherapy. Here, we provide preclinical evidence supporting the suitability of allogeneic human V{gamma}9V{delta}2 T cells for ACT. We characterized peripheral blood V{gamma}9V{delta}2 T cells from healthy donors after successive antigen-specific and non-specific amplification steps, assessing their phenotype, effector functions, and metabolic state. Amplified cells maintained a strong pro-inflammatory Th1-like profile, preserved cytotoxic activity, and did not produce immunoregulatory cytokines. They also displayed high purity, a predominant effector memory phenotype, reduced expression of several inhibitory immune checkpoints, and sustained antitumor reactivity. Altogether, these findings support the development of allogeneic V{gamma}9V{delta}2 T-cell products as a scalable platform for next-generation cancer immunotherapies.

BackgroundNeoadjuvant chemoimmunotherapy (nCIT) has become a standard treatment for locally advanced resectable non-small cell lung cancer (NSCLC), yet the spatial biology underlying treatment resistance remains poorly understood. We used spatial transcriptomics to define the microenvironmental architecture of residual cancers in patients who did not achieve major pathologic response (non-MPR) compared with those who did (MPR). MethodsSpatial transcriptomics was performed on 10 formalin-fixed paraffin-embedded (FFPE) tumor blocks (5 MPR, 5 non-MPR) obtained from 8 patients treated with nCIT. A deep learning algorithm was applied to detect viable residual cancer spots from treatment-induced fibrosis and necrosis. Spatial deconvolution, distance modeling, ligand-receptor analysis, and functional pathway scoring were integrated to characterize niche-specific programs. ResultsMPR cancer core displayed an immune-permissive remodeling environment with deep infiltration of cytotoxic CD8+ T cells, mature dendritic cells (LAMP3+, CCR7+), and active efferocytosis signaling (APOE-TREM2), alongside robust MHC class II expression. Non-MPR cancer core, by contrast, exhibited spatial immune exclusion: a dense fibroblast barrier reinforced by TIMP1-CD63 signaling and Treg-enriched boundaries physically restricted effector T cell access to the cancer core. Residual cancer cells in non-MPR samples maintained active cell cycling and independently upregulated cytochrome P450-mediated drug detoxification and DNA damage response pathways without inducing MHC class II expression -- effectively decoupling intrinsic survival from immune recognition. The non-MPR core also showed a hyper-metabolic profile, including elevated glutathione metabolism consistent with antioxidant buffering against chemotherapy-induced oxidative stress. TROP2 was broadly expressed across the non-MPR cancer core and co-localized with DNA damage response and nuclear factor erythroid 2-related factor 2 resistance signatures. ConclusionsResidual cancer cores in non-MPR tumors appear to represent evolved resistant niches sustained by structural immune exclusion, metabolic rewiring, and DNA repair proficiency. These findings highlight the spatial co-localization of epithelial anchors, such as TROP2, with intrinsic resistance pathways, providing a structural rationale for developing novel precision therapeutic strategies to bypass stromal barriers and overcome the cancer cores intrinsic repair capacity.

Junctional adhesion molecule-like (JAML) is an adhesion molecule known to promote T cell activation and T cell-mediated tumor rejection. In the current study, we show that JAML expression is enriched on mouse intratumoral NK cells compared with splenic NK cells. JAML+ NK cells were associated with tissue residency and co-expressed the immune checkpoints PD-1 and LAG3. JAML expression could be induced on splenic NK cells by IL-2 and further enhanced by IL-21. JAML levels were inversely correlated with inhibitory signaling, as NK cells expressing self-recognizing Ly49 receptors had reduced JAML expression, suggesting regulation of JAML expression by MHC class I molecules. Interaction with the JAML ligand CXADR also reduced JAML surface expression, indicating that tumor-mediated membrane stripping may represent a mechanism of immunoediting. Although JAML RNA transcripts were detectable in human NK cells, JAML protein was found only intracellularly. Together, these findings identify the JAML-CXADR interaction as a potential regulatory pathway in NK cell-mediated killing of tumors.

BackgroundPancreatic adenocarcinoma (PDAC) is an abysmal disease, with a poor clinical outcome, largely due to limited life-extending treatments for patients. Notoriously, PDAC displays a T cell-suppressive tumor microenvironment where underlying molecular mechanisms that lead to this phenotype remain poorly understood. To unravel specific mechanisms, we utilized bioinformatic analyses with functional studies and revealed the cytolinker protein plectin (PLEC) as a novel player in regulating the T cell-suppressive tumor microenvironment of PDAC. MethodsUtilizing the TCGA-PAAD dataset, tumor samples were separated by PLEC expression to evaluate patient survival, and pathway analyses associated with increased tumorigenesis. Evaluation of immune infiltration and subsequent immune deconvolution was performed using tidyestimate and CIBERSORTx R packages. Single-cell RNA-seq (scRNA-seq) analysis from 229 PDAC patients was analyzed to investigate signaling dynamics and immune cell infiltration in PLECHigh patients. Functional validation was provided using a monoclonal antibody (mAb) against cell surface plectin (CSP) in two murine PDAC models to examine changes in tumor growth and immune cell subset abundance. ResultsOur studies revealed that high plectin expression results in an overall worse survival associated with activation of pro-tumorigenic pathways and decreased anti-tumor immune signature in PDAC patients. Analysis via GSEA indicates PLECHigh patients display an aggressive phenotype and suppressed pro-inflammatory signaling pathways. Immune ESTIMATE scores were significantly decreased in PLECHigh patients, and scRNA-seq analysis revealed that PLECHigh tumors display a decrease in anti-tumor CD8+ T cells. In vivo analyses using an anti-CSP mAb revealed a reduction in tumor growth kinetics compared to IgG control corresponding with a significant increase in proliferating and activated cytotoxic CD8+ T cells. Anti-CSP-mediated tumor suppression was inhibited when CD8+ T cells were depleted, indicating that anti-CSP treatment is contingent on cytotoxic T cell functionality. ConclusionOur findings identify plectin as a biomarker of aggressive disease in PDAC, with high plectin expression associated with decreased T cell infiltration, and that treatment with anti-CSP mAb reinstates anti-tumor immunity and decreases tumor volume in vivo. These findings position plectin as a high-priority therapeutic target, with the potential to fundamentally reshape immune responses in PDAC and improve outcomes for patients with few remaining options.

Chimeric antigen receptor (CAR) T-cell therapy has transformed treatment for relapsed /refractory(r/r) lymphoid malignancies. Yet, these cellular immunotherapies are often associated with immune-related adverse events (irAEs), namely cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), that pose significant risks to patient safety and limit broader clinical implementation of CAR T-cell therapies. In the current study, we used proteomics technology to establish circulating protein signatures that would predict severe CRS and ICANS in r/r lymphoma patients that subsequently received CAR T-cell therapy. Initial discovery was performed using plasma samples collected preceding CAR T-cell infusion from 39 r/r lymphoma patients at MD Anderson Cancer Center. A 5-marker and 8-marker protein panel was developed for predicting Grade [≥] 2 CRS and ICANS respectively, yielding respective AUCs of 0.85 [95% CI: 0.72-0.98] and 0.91 [95% CI: 0.81-1.00]. Independent testing of the CRS and ICANS panel was performed in a cohort of 59 r/r lymphoma patients from the Moffitt Cancer Center, with resultant AUCs of 0.76 [95% CI: 0.63-0.89] and 0.67 [95% CI: 0.51-0.84] for the CRS and ICANS panel, respectively. Patients were further classified into low-, intermediate-, and high-risk groups based on panel score tertiles. In the combined dataset (MDACC + Moffitt), compared to patients in the low-risk group (reference), patients in the intermediate- and high-risk groups were 3.15 [95% CI: 0.92-12.71] and 13.84 [95% CI: 4.21-56.26] more likely to have Grade [≥] 2 CRS, and 1.21 [95% CI: 0.36-4.23] and 8.59 [95% CI: 2.87-29.09] more likely to have Grade [≥]2 ICANS. The protein biomarker panels provide a means to risk stratify patients who are at high risk for developing severe CRS and ICANS, to inform on the need for prophylactic interventions and improve patient outcomes.

BackgroundTreatment optimization in HPV-associated oropharyngeal cancer (OPSCC) remains challenging, as recent de-escalation trials have shown limited success. Current patient selection strategies based on smoking history and TNM classification are insufficient, highlighting the need for robust, standardized prognostic biomarkers. We report the first validation of the Immunoscore (IS) for prognostic stratification in HPV-associated OPSCC. Patients and methodsWe analyzed 191 HPV-associated (p16+ and HPV DNA/RNA+) OPSCC patients from an international multicenter cohort (2015-2024), comprising a French monocentric retrospective training cohort (N = 48) and three validation cohorts: French monocentric retrospective (N = 48), French multicenter prospective (N = 50), and US multicenter retrospective (N = 45). IS is a standardized digital pathology assay quantifying CD3lJ and CD8lJ densities in tumor cores and invasive margins, with cut-offs defined in the training cohort and validated across cohorts. Associations with disease-free survival (DFS), time to recurrence (TTR) and overall survival (OS) were assessed, alongside 3RNA-seq and sequential immunofluorescence profiling of immune composition. ResultsMedian age 65; 80% male; 74% smokers; 66% T1-2; 82% N0-1 (AJCC8th). IS-High patients demonstrated superior 3-year DFS in the training and validation cohorts 1-3 (all log-rank P < 0.05). Multivariable analysis identified IS-Low as the strongest independent risk factor for DFS (HR 9.03; 95% CI: 4.02-20.31; P < 0.001). The model combining IS with clinical factors showed higher predictive accuracy for DFS (C-index 0.82) than clinical variables alone (0.7; P < 0.0001). Similar findings were observed for TTR and OS. IS-High tumors showed markedly higher enrichment of lymphoid and myeloid immune cell populations, contrasting with immune-poor signatures in IS-Low tumors. ConclusionsIS is a robust biomarker that outperforms standard clinical variables in both prognostic and predictive accuracy. The enriched cytotoxic immune infiltrate in IS-High tumors explains favorable outcomes and supports their suitability for treatment de-escalation. Prospective validation is warranted.

Malignant peripheral nerve sheath tumours (MPNSTs) are high grade soft-tissue sarcomas with an unmet need for novel therapies. Tumour antigen-based approaches, including neoantigen and tumour-associated antigen (TAA) directed therapies, offer potential opportunities for immunotherapy. Here, we integrated public domain tumour DNA and RNA sequencing data with in-silico prediction to systematically characterise the (neo)antigenic landscape of MPNST. We stratified the predictions across the two known sub-groups of MPNST, those associated without and with Polycomb Repressor Complex 2 (PRC2) loss of function variants (PRC2-Loss). Using computational pipelines including pVACtools, we identified high-confidence neoantigens based on pMHC affinity derived from somatic mutations and gene fusions, as well as recurrently overexpressed cell-surface TAAs. All predicted neoantigens were private to individual MPNST cases, with different neoantigens across both tumour subtypes. PRC2-Loss tumours showed reduced immune infiltration with downregulation of antigen processing and presentation pathways compared to PRC2-WT, confirming intrinsic constraints to effective neoantigen-directed immune priming. Moreover, PRC2-Loss MPNSTs demonstrated recurrent copy number driven overexpression of cell surface TAAs (chromosome 8), providing alternative immunotherapeutic targets that are pMHC independent. These findings confirm a PRC2-independent private immuno-antigenic peptide repertoire with an immune resistant MPNST microenvironment in PRC-Loss. These data provide further impetus for rational development of complementary immune based treatment strategies, including personalised neoantigen vaccines and cell surface protein TAA-directed therapies dependent on PRC2 status.

1.The ABACUS study was a single arm, phase II trial evaluating neoadjuvant atezolizumab in operable urothelial carcinoma (UC). Initial bulk transcriptomic and immunohistochemistry analyses suggested links between immune activation, tissue remodeling, and resistance pathways such as transforming growth factor {beta} (TGF{beta}) that were associated with clinical outcome. To further characterize spatial and phenotypic changes at high resolution, artificial intelligence-assisted digital image analysis of hematoxylin and eosin sections and spatial transcriptomics (10x Genomics Visium) were performed on paired tissue samples. In baseline samples, cells residing in lymphoid aggregates and tertiary lymphoid structures (LAs/TLSs) were more abundant in stable disease than in relapse and exhibited gene expression programs associated with improved survival in UC. Most spatial features reflected shared pharmacodynamic changes between stable disease and relapse; however, carcinoma-endothelial adjacency was reduced significantly following treatment and differed between groups, accompanied by distinct transcriptional programs. Together, these findings indicate that atezolizumab induces localized immune and stromal remodeling within the tumor microenvironment, while non-response despite immune expansion is associated with persistent spatial immune exclusion and carcinoma-endothelial adjacency. Spatial and phenotypic biomarkers identified here may inform rational combination strategies for immune checkpoint inhibitor-refractory urothelial carcinoma.

BackgroundImmune checkpoint inhibitors (ICIs) have improved outcomes across multiple cancer types, yet reliable predictors of survival remain limited. While genomic features such as tumor mutational burden (TMB) are widely used, their contribution to predictive modeling in heterogeneous real-world cohorts remains unclear. We evaluated the relative contributions of clinical and whole-genome sequencing (WGS) features in pan-cancer survival modeling. MethodsWe analyzed 658 patients treated with ICIs with matched WGS data from the Genomics England. Using a leakage-controlled machine learning framework with strict train-test separation, we compared four models: TMB-only, clinical-only, clinical+TMB, and an integrated 11-feature clinico-genomic XGBoost survival model. Model performance was assessed using Harrells concordance index (C-index) with bootstrap confidence intervals. ResultsTMB alone demonstrated near-random discrimination (C-index 0.50; 95% CI 0.44-0.56). Clinical variables substantially improved predictive performance (0.59; 95% CI 0.53-0.64), with marginal gain from adding TMB (0.59). The integrated model achieved a C-index of 0.60 (95% CI 0.55-0.65). While improvement over TMB alone was significant, incremental gain beyond optimized clinical models was modest. Feature attribution analysis showed that model performance was dominated by clinical variables, with genomic features contributing limited additional signal. ConclusionsThese findings suggest that, in heterogeneous pan-cancer cohorts, predictive performance is constrained by the underlying data structure, in which dominant clinical signals overshadow genome-scale features. This study highlights fundamental limitations in integrating genomic data into survival models across diverse cancer types and provides a benchmark for future computational approaches.

Given the critical role of CD4 T cells in anti-tumor immunity, strategies to harness these cells for cancer immunotherapy are gaining increasing interest. Historically overshadowed by CD8 T cells, cytotoxic CD4 T cells can directly kill MHC class II-expressing tumor cells. However, the defining molecular signature and the mechanisms underlying their cytolytic activity remain poorly understood, particularly in cancer patients. Here, using ex vivo single-cell transcriptomic and spatial analyses of CD4 T cells from paired blood and tumor samples of melanoma patients, we identified Killer Cell Lectin-Like Receptor G1 (KLRG1) as a defining surface marker of cytotoxic CD4 T cells. The CD4+ KLRG1+ T cell subset was notably enriched among circulating cells compared with tumor-infiltrating populations, which were instead enriched in T follicular helper (Tfh) states. Functionally, KLRG1+ CD4 T cells expressed elevated levels of cytotoxic genes and exhibited superior tumor-killing capacity compared with their KLRG1- counterparts. We demonstrated that their cytotoxicity is granulysin-dependent, as confirmed by CRISPR/Cas9-mediated gene deletion. Mechanistically, CD4 T cells spared MHC class II+ cells lacking the KLRG1 ligands CD324 and CD325, such as professional antigen-presenting cells (APCs), indicating that cytotoxicity was selectively directed towards tumor cells while preserving immune cells. Finally, by investigating how the tumor microenvironment may impair CD4 T cell cytotoxicity, we showed that tumor-derived factors, including interleukin-6 (IL-6), are key drivers promoting the transition of cytotoxic CD4 T cells toward a Tfh phenotype. In summary, our findings define KLRG1 as a defining cell surface marker of cytotoxic CD4 T cells in cancer patients, as well as a key regulator that protects MHC class II+ APCs. Moreover, targeting the IL-6 signalling pathway may enhance CD4 T cell anti-tumor cytotoxicity, offering new avenues for cancer immunotherapy.

Abstract / SummarySurvival outcomes for pediatric Burkitt lymphoma (BL) substantially vary depending on geography (50-90%), which also serves as a proxy for the prevalence of Epstein-Barr virus (EBV) within the tumors. Although BL is considered an immunologically "cold" tumor with few tumor-infiltrating lymphocytes (TILs), their functional status has not been fully evaluated, especially for EBV-positive disease. Here, we characterize the exhaustion and activation profiles of T cells in the tumor microenvironment (TME) of EBV-positive BL using orthogonal methods, single-cell gene expression analysis, spectral flow cytometry, and immuno-histochemistry staining (IHC). We found that CD8+ TILs displayed a mosaic of immune inhibitory gene expression encoding, PD1, TIGIT, LAG3 and HAVCR2/TIM3. IHC validated the expression of PD1 and TIGIT on CD8+ TILs, as well as their respective ligands, PDL-1, PVR, and Nectin-2 on malignant B cells. Despite exhaustion-associated signatures, CD8+ TILs retain cytotoxic potential, expressing granules (i.e. Granzyme A, Perforin) and cytokines (i.e. IFN{gamma}) and demonstrate an increased uptake of metabolites such as glucose, arginine, and methionine. In peripheral blood, pediatric BL patients exhibited a significantly higher abundance of PD1+TIGIT+ CD8+ T cells compared to healthy children. Notably, these circulating T cells from BL patients express significantly lower levels of TOX, suggesting they are not irreversibly dysfunctional. Together, our results indicate that CD8+ T cells both in the TME and in circulation of children with BL are not terminally exhausted but remain poised for functional re-invigoration. These findings support the potential integration of immune checkpoint inhibitors into combination chemotherapeutic regimens to improve outcomes for these children. SignificanceEBV-positive BL tumors contain functional, metabolically active CD8+ T cells. Circulating PD1+TIGIT+CD8+ T cells found in BL patients blood are a biomarker for those in the tumor microenvironment.

B7-H3 (CD276) is an immune checkpoint molecule frequently overexpressed in hepatocellular carcinoma (HCC) and represents a promising therapeutic target. However, its roles in tumor cell adhesion, metastatic behavior and immune evasion--particularly in interactions with natural killer (NK) cells--remain incompletely understood. In the present study, B7-H3 was depleted using small interfering RNA and CRISPR/Cas9 in epithelial (Huh7 and HepG2) and mesenchymal (SNU449) HCC cell lines. Tumor cell survival, apoptosis, adhesion, migration and invasion were evaluated using functional assays. Expression of adhesion molecules and immune checkpoint proteins was assessed by flow cytometry and western blotting. Oncogenic signaling pathways were analyzed by examining phosphorylation of Akt, ERK, FAK and STAT3. NK cell-mediated cytotoxicity was assessed using primary human NK cells. B7-H3 depletion reduced clonogenic survival and increased apoptosis in mesenchymal HCC cells under anchorage-independent conditions. Loss of B7-H3 impaired cell adhesion, migration and invasion, accompanied by downregulation of PTGFRN, E-cadherin, integrin 3 and integrin V, and reduced cell-to-cell aggregation under anchorage-independent conditions. B7-H3 depletion also decreased surface expression of PD-L1, PD-L2 and CD47. Notably, B7-H3-deficient cells exhibited enhanced susceptibility to primary NK cell-mediated cytotoxicity. Mechanistically, B7-H3 promoted tumorigenic signaling through Akt/S6, MVP/ERK and FAK/Src pathways in epithelial cells, and through FAK/Src and JAK2/STAT3 pathways in mesenchymal cells. Together, these findings reveal previously unrecognized roles for B7-H3 in coordinating adhesion and NK immune evasion in HCC, and support its therapeutic targeting for next-generation immunotherapies.

We studied the effect of stimulating innate immune function in tumor-associated myeloid cells (TAMs) in medulloblastoma (MB) and diffuse midline glioma (DMG), using a polyoxazoline nanoparticle formulation of the TLR7/8 agonist resiquimod (ResiPOx). Children with MB and DMG need novel therapeutic strategies to improve outcomes and reduce recurrence. We investigated the effect of systemically administered ResiPOx on TAMs in MB and DMG using endogenous MB and DMG models in immune-competent mice and identified multiple mechanisms of anti-tumor effect. We packaged resiquimod into polyoxazoline micelles to generate ResiPOx. We studied ResiPOx efficacy as a single agent or paired with radiation therapy (RT). We determined ResiPOx pharmacokinetics (PK) using tritium-labeled resiquimod and mass spectroscopy imaging (MSI). We determined ResiPOx pharmacodynamics (PD) using flow cytometry immunohistochemistry, bulk and single-cell RNA-seq and immunoblotting. We then studied ResiPOx safety and PD in a non-human primate model using rhesus macaques. ResiPOx formulation improved the blood-brain barrier penetration and anti-tumor efficacy of resiquimod. ResiPOx treatment extended progression-free survival (PFS) in mice with MB and DMG. In both tumor types, ResiPOx expanded TAM populations and reprogrammed TAMs toward anti-tumoral states, characterized by activation of IFN{beta} and extrinsic apoptosis pathway signaling, antigen presentation, and T cell activation signatures. In rhesus macaques, systemic ResiPOx administration was well tolerated and induced brain transcriptional responses that resembled ResiPOx responses in DMG and MB mouse models, indicating common effects across species from mice to non-human primates, and highlighting potential for similar effects in patients. ResiPOx is a brain-penetrant immunomodulatory therapeutic that reshapes the immune-privileged brain tumor microenvironment. Systemic administration activates myeloid-driven anti-tumoral immunity mediated by microglial and macrophage TAMs, and improves survival in preclinical models of DMG and MB.

Background: Sezary syndrome (SS) is an aggressive leukemic variant of cutaneous T-cell lymphoma (CTCL) with distinct clinical and biological features compared to rarer entities such as primary cutaneous CD8+ aggressive epidermotropic cytotoxic T-cell lymphoma (PCAECTCL). Although recurrent genomic alterations in CTCL have been described, comparative analyses at the pathway level across biologically divergent subtypes remain limited. Here, we leveraged a conversational artificial intelligence (AI) platform for precision oncology to enable rapid, integrative, and hypothesis-driven interrogation of publicly available genomic datasets. Methods: We conducted a secondary analysis of somatic mutation and clinical data from the Columbia University CTCL cohort accessed via cBioPortal. Cases were stratified into SS (n=26) and PCAECTCL (n=13). High-confidence coding variants were curated and mapped to biologically relevant signaling pathways and functional gene categories implicated in CTCL pathogenesis. Pathway-level mutation frequencies were compared using Chi-square or Fisher's exact tests, with effect sizes quantified as odds ratios. Tumor mutational burden (TMB) was compared using the Wilcoxon rank-sum test. Subtype-specific co-mutation patterns were evaluated using pairwise association analyses and visualized through oncoplots and network heatmaps. Conversational AI agents, AI-HOPE, were used to iteratively refine cohort definitions, prioritize pathway-level signals, and contextualize findings. Results: TMB was comparable between SS and PCAECTCL (p = 0.96), indicating no significant difference in global mutational load. In contrast, pathway-centric analyses revealed marked qualitative differences. SS demonstrated enrichment of alterations in epigenetic regulators, tumor suppressor and cell-cycle control pathways, NFAT signaling, and DNA damage response mechanisms, consistent with transcriptional dysregulation and immune modulation. PCAECTCL exhibited relatively higher frequencies of alterations involving epigenetic regulators and MAPK pathway signaling, suggesting distinct oncogenic dependencies. Co-mutation analysis revealed a more constrained and focused interaction landscape in SS, whereas PCAECTCL displayed broader and more heterogeneous co-mutation networks, indicative of divergent evolutionary trajectories. Notably, ERBB2 mutations were significantly enriched between subtypes (p = 0.031), highlighting a potential subtype-specific therapeutic vulnerability. Conclusions: This study demonstrates that SS is distinguished from PCAECTCL not by increased mutational burden but by distinct pathway-level architectures, particularly involving epigenetic regulation, immune signaling, and transcriptional control. These findings generate biologically grounded, testable hypotheses for subtype-specific therapeutic targeting and underscore the value of conversational AI as a scalable framework for accelerating discovery in translational cancer genomics.

Chimeric antigen receptor (CAR) T cell therapy utilizes genetically engineered patient-derived T cells to target cancer cells. Despite its clinical successes in multiple cancer types, the underlying molecular mechanisms by which molecules on CAR-T cells and surrounding cells interact with other proteins and collectively determine treatment efficacy remain elusive. Most previous studies have relied on transcriptome profiling, which does not fully reflect protein-level organization and interactions. In this study, we developed an antibody-oligonucleotide conjugate targeting the FMC63 region of CAR and integrated it into molecular pixelation (MPX). This approach enabled profiling of the dynamics of CAR molecules on cell surfaces as well as their colocalization with other proteins at the single-cell level. By applying MPX to longitudinal samples from three patients undergoing CAR-T cell therapy, we characterized the dynamic changes in CAR-associated protein organization in both pre-infusion CAR products and post-infusion peripheral blood. While CAR protein abundance and polarization showed limited variation across clinical courses, remodeling of a CAR-centered co-localization network was observed over time, including different retentions of specific molecular associations between patients with different clinical outcomes. Although derived from a limited cohort, our study identifies insights from this methodological framework beyond those gained by conventional omics analyses and offers results of a systematic investigation to predict and enhance CAR therapeutic outcomes. Key pointsO_LIMolecular pixelation was applied for chimeric antigen receptor (CAR) profiling at single-molecule and single-cell resolutions. C_LIO_LIProtein and transcriptome analyses of the CAR molecule showed dynamic remodeling during CAR-T therapy in patients with non-Hodgkin lymphoma. C_LI

T cell lymphomas (TCL) are a heterogeneous collection of malignancies whose origins and pathogenesis are poorly understood and for which few efficacious therapeutic options exist. Here, we conduct single-cell transcriptomic profiling spanning eight TCL entities and describe entity-associated programmes. We predict the cell of origin for these tumours through an integrative analysis of transcriptome and T cell receptor (TCR) maturation states. By identifying tumours with TCR states ranging from the pre-TCR through non-productive and productive TCR alpha and beta chain rearrangements we shed new light on their developmental origins. Furthermore, we apply our drug2cell computational drug target predictions with drug screens using patient-derived cell models, systematically benchmarking the performance of drug2cell and validating compounds and targets. This process identifies SYK inhibitors as a therapeutic opportunity and prioritises TIM3 for immunotherapy based on combined spatial transcriptomics analysis. Overall, our data provide a resource for diagnostics and therapies for tumours of critical unmet need.