Granular hydrogels are an emerging biomaterial platform increasingly used in biomedical applications, including therapeutic delivery and tissue regeneration. Assembled from micron-scale hydrogel particles through physical assembly or chemical cross-linking, granular hydrogels possess micro- and macroscopic pores that facilitate molecular transport and cell migration. However, current granular hydrogels are typically fabricated with defined stiffness, porosity, and compositions that do not recapitulate the dynamic nature of native tissues, including the tumor microenvironment. To address this challenge, we have developed dynamic granular hydrogels formed by gelatin-norbornene-carbohydrazide (GelNB-CH) microgels. GelNB-CH microgels were first prepared from a microfluidic droplet generator coupled with the rapid thiol-norbornene photo-click gelation. The collected microgels were annealed via inverse electron-demand Diels-Alder (iEDDA) click reaction to form granular hydrogels, which were dynamically stiffened via hydrazone bonding. Notably, adjusting the concentration of the stiffening reagent (i.e., oxidized dextran, oDex) enabled dynamic stiffening of the granular hydrogels without affecting the void fraction. Pancreatic cancer-associated fibroblasts (CAFs) seeded in the granular hydrogels spread rapidly throughout the scaffold and induced cancer cell migration. This work enhances the design of granular hydrogels, offering a highly adaptable biomaterial platform for in vitro cancer modeling.

Diffuse pleural mesothelioma (PM) is a rare malignant neoplasm with an extremely poor prognosis. Prognostic assessment remains challenging, highlighting the urgent need for reliable biomarkers to guide precise and effective therapy. Programmed death ligand 1 (PD-L1) has been suggested as a predictive biomarker for PM, but existing data are limited and controversial. Although advances have been made in understanding cancer-associated fibroblasts (CAFs) within the PM tumor microenvironment, their clinical and prognostic significance remains poorly elucidated. A retrospective analysis of 51 pathologically diagnosed PM was performed. We evaluated clinicopathological factors (including tumoral PD-L1, stromal α-SMA, and Ki-67 percentage by immunohistochemistry) and analyzed their correlation with overall survival (OS) using Kaplan-Meier and multivariate Cox regression. A total of 12 potential prognostic factors were evaluated in the univariate analysis, and 6 factors were found to be significantly associated with a poor prognosis in PM patients. Multivariate analysis identified histological classification, TNM stage, and PD-L1 expression as independent prognostic factors in PM patients. Stromal α-SMA positivity, a marker of poor prognosis, was significantly correlated with male, non-epithelioid subtype, and a high Ki-67 index. Moreover, α-SMA positivity tended to show an increased likelihood of PD-L1 expression (p = 0.065). The expression of tumor PD-L1 could serve as an adverse prognostic factor for PM patients. Its potential association with tumor stromal α-SMA expression warrants further investigation, particularly in the context of unmet needs in tumor immunotherapy.

Deconvolution of bulk RNA-expression data unlocks the cellular complexity of cancer, yet traditional pseudobulk benchmarks may not always be reliable in real-world settings where absolute cell proportions are unknown. Here, we introduce a novel real-data framework, leveraging 18 real bulk RNA-expression cohorts (5,891 samples) across nine cancer types to evaluate five deconvolution methods based on differentially proportioned (DP) and prognosis-related (PR) cell types. Across three innovative benchmark scenarios-consistency with scRNA-seq, reproducibility across cohorts, and reproducibility of prognostic relevance-ReCIDE and BayesPrism stand out as two robust deconvolution methods. Application of a pan-cancer analysis based on the deconvolution of TCGA cohorts identifies matrix cancer-associated fibroblasts (mCAF) as a prognostic marker with consistent effects across multiple cancers. Building on this finding,we find a prognostic indicator combining classical monocytes and mCAF cell proportions to be significant in five TCGA cohorts, which we further validate in five independent GEO cohorts. This study broadens deconvolution benchmarking, offering actionable tools for precision oncology and guiding method selection for translational research.

Gastric cancer ranks as the fifth most prevalent malignancy and the fifth leading cause of cancer-related mortality worldwide, with stomach adenocarcinoma (STAD) being the predominant pathological type. Despite a decline in STAD incidence in recent years, factors such as an aging population may contribute to an increase in future cases. Current clinical management of STAD primarily involves surgical resection, radiation, chemotherapy, and emerging immune checkpoint blockade (ICB) therapies. However, the limited efficacy of ICB monotherapy in most patients with STAD highlights the need for novel therapeutic targets. This study investigated the role of versican (VCAN) in STAD. Comprehensive analysis of multiple databases revealed significantly higher VCAN expression in STAD tissues compared to normal tissues, correlating with poor patient prognosis. Single-cell analysis further identified VCAN as predominantly secreted by cancer-associated fibroblasts (CAFs), especially the pan-pCAF subtype. CAFs with elevated VCAN levels promoted the proliferation, migration, and invasion of high-stemness adenocarcinoma cells via the MDK-NCL and MIF-CD74-CD44 signaling pathways, while also enhancing immune evasion and self-renewal. These results position VCAN as a potential new therapeutic target for STAD.

Background: Fibroblast activation protein inhibitor (FAPI) positron emission tomography (PET) has emerged as a promising modality for imaging the tumor microenvironment, specifically targeting cancer-associated fibroblasts (CAFs). While 18F-FDG targets glucose metabolism, 68Ga-FAPI targets stromal activation. Discrepancies between these modalities can offer unique insights into early pathogenesis. We report a rare case of incidental focal pancreatic uptake on 68Ga-FAPI PET/CT in a patient with prostate cancer, occurring in the absence of metabolic activity on 18F-FDG PET/CT or anatomical abnormalities on contrast-enhanced CT. Case presentation: A 75-year-old male with a history of acinar adenocarcinoma of the prostate (Gleason 7, post-TURP) underwent multimodal staging to evaluate for metastasis. 68Ga-PSMA PET/CT showed intermediate uptake in the prostate but no distant metastasis. Subsequent 68Ga-FAPI-04 PET/CT revealed a striking, intense focal uptake in the pancreatic body. Conversely, follow-up 18F-FDG PET/CT demonstrated physiological background uptake in the pancreas, and abdominal CT showed no pancreatic mass. Laboratory results indicated a slightly elevated CA 19-9 (45.6 U/mL). The findings present a diagnostic dilemma between early stromal-rich malignancy and focal inflammatory processes. Conclusion: This case highlights the FAPI-FDG Mismatch, suggesting that stromal remodeling may precede metabolic reprogramming and morphological changes in pancreatic lesions. 68Ga-FAPI PET/CT demonstrates superior sensitivity for detecting occult stromal activity, necessitating new diagnostic algorithms for incidentalomas in the era of stromal imaging.

Ovarian cancer is the deadliest gynecologic cancer, mainly because it is often diagnosed late and resists standard treatments. The tumor microenvironment (TME) plays a major role in disease progression and therapy failure. Two key components of the TME, cancer-associated fibroblasts (CAFs) and tumor-associated macrophages (TAMs), create conditions that facilitate tumor growth and immune evasion. CAFs are highly diverse and originate from sources like fibroblasts and stem cells. They support cancer by remodeling the extracellular matrix, promoting angiogenesis, and releasing cytokines and growth factors that aid tumor survival. TAMs, which are usually in an M2 state, also promote metastasis and suppress immune responses by secreting immunosuppressive molecules. Together, CAFs and TAMs interact with cancer cells to activate pathways such as the TGF-β, IL-6, and PI3K/AKT pathways, which drive resistance to therapy. New treatments aim to block these interactions by targeting CAFs and TAMs through depletion, reprogramming, or pathway inhibition, often combined with immunotherapy. Advances such as single-cell sequencing and spatial transcriptomics now enable more precise identification of CAF and TAM subtypes, enabling more targeted therapies. This review summarizes their roles in epithelial ovarian cancer and explores how targeting these cells could improve outcomes.

Chimeric antigen receptor T (CAR-T) cell therapy has revolutionised the treatment of hematologic malignancies, achieving durable and robust responses. However, the application of CAR-T cells in solid tumours remains limited by a complex network of barriers, most notably poor tumour infiltration. The key obstacles include mismatch between chemokines and receptors, abnormal tumour vasculature, immunosuppressive cellular populations (such as myeloid-derived suppressor cells, tumour-associated macrophages and regulatory T cells), dense network of cancer-associated fibroblasts and extracellular matrix, T cell dysfunction and exhaustion, metabolic limitations within the tumour microenvironment, tumour heterogeneity and transport limitations related to tumour location. By integrating mechanistic insights with innovative bioengineering and combination approaches, this review systematically elaborates on the factors that limit the infiltration of CAR-T cells and emphasises transformation strategies for improving the efficacy, durability and invasiveness of treating solid tumours.

Background: Cancer-associated fibroblasts (CAFs) are key mediators of metastatic progression in non-small cell lung cancer (NSCLC). Fibroblast activation protein (FAP) serves as the hallmark of CAF activation. However, the upstream regulation of FAP remains elusive, limiting stroma-targeted therapy development. Methods: 68Ga-FAP inhibitor (FAPI)-04 PET/CT imaging was performed on 61 NSCLC patients to evaluate the clinical significance of FAP. CAFs and normal fibroblasts (NFs) were isolated from patient tissues. Bioinformatic analysis and qRT-PCR were employed to screen and validate miRNAs. Functional assays (CCK-8, collagen contraction, wound healing, transwell co-culture) were utilized to investigate the role of miR-624-5p in regulating fibroblast activation and the effects on the metastatic potential of NSCLC cells. The targeting relationship between miR-624-5p and FAP was validated using FISH, dual-luciferase assay, and Western blotting. Results: 68Ga-FAPI-04 uptake was higher in advanced NSCLC (p < 0.001) and correlated with tumor size, lymph node metastases, and distant metastases (p < 0.05). Isolated primary CAFs significantly enhanced the migration and invasion of A549 and PC9 cells compared to NFs (p < 0.001). We identified miR-624-5p as a significantly downregulated miRNA in CAFs (p < 0.001). Functionally, miR-624-5p overexpression inhibited CAF proliferation and collagen contraction (p < 0.01) and reduced the proliferation, migration, and invasion capabilities of A549 and PC9 cells (p < 0.001). Mechanistically, miR-624-5p bound to FAP mRNA and negatively regulated FAP expression (p < 0.001), thus suppressing CAF activation and tumor metastasis. Conclusions: Our findings establish miR-624-5p as a novel upstream regulator that suppresses FAP expression, consequently inhibiting CAF activation and its pro-metastatic function. Targeting the miR-624-5p/FAP axis represents a promising therapeutic strategy for NSCLC metastasis.

Oncological safety is essential for autologous reconstruction after resection of cartilage-infiltrating head and neck tumors. High hydrostatic pressure (HHP) enables complete devitalization of tumor-infiltrated tissue while preserving extracellular matrix integrity. However, residual soluble tumor-derived products may influence infiltrating stromal cells. This study examined whether conditioned media (CM) from HHP-treated head and neck squamous cell carcinoma (HNSCC) cells induce cancer-associated fibroblast (CAF)-like transdifferentiation of human adipose stromal cells (hASCs). HASCs were exposed to CM from untreated or HHP-treated (300 MPa) HNSCC cells, tumor-CM (TCM), or TGF-β1. Morphological changes in hASCs were evaluated, and CAF marker expression was analyzed by qRT-PCR, immunofluorescence, Western blot, and ELISA. Cytokines were quantified via multiplex analysis. TGF-β1 induced a CAF-like phenotype with α-SMA upregulation, whereas TCM and 0 MPa-CM caused only modest increases in selected markers. Although 300 MPa-CM did not induce CAF-associated molecular signatures, hASCs exhibited morphological alterations, underscoring that morphology alone is insufficient to define CAF transdifferentiation. Cytokine secretion was elevated in response to all CM conditions. These findings indicate that HHP treatment at 300 MPa abolishes the paracrine CAF-inducing potential of tumor-derived mediators in vitro, supporting the oncological safety of HHP-treated tissues under these experimental condition, although further in vivo validation is warranted

Lactate in the tumor microenvironment (TME) is typically generated by cells exhibiting high glycolytic flux, exemplified by tumor cells. However, in glycolysis-low malignancies such as prostate cancer, stroma-derived lactate may drive noncanonical signaling and functions that remain unclear. Here, we identified APCDD1+ cancer-associated fibroblasts (CAFs) as a distinct stromal population that secretes lactate into the TME in response to androgen deprivation therapy (ADT). Lactate uptake by prostate cancer cells induces androgen receptor variant 7 expression, thereby conferring resistance to ADT. Mechanistically, lactate-induced lactylation of the spliceosome component SNRPA at Lys123 (K123) enhances its recognition of cis-acting elements, increases chromatin binding, and promotes androgen receptor splicing. Targeting lactate transport with monocarboxylate transporter inhibitors effectively restores ADT sensitivity. These findings reveal a metabolic-epigenetic axis linking lactate in the microenvironment to alternative splicing regulation and suggest a promising therapeutic strategy to overcome ADT resistance.

Urokinase plasminogen activator receptor–associated protein (uPARAP) is a collagen-internalizing receptor with emerging relevance as a therapeutic target. The involvement of uPARAP in extracellular matrix turnover and stromal remodeling within the tumor microenvironment (TME) makes it an especially promising target in tumors with a high stromal component. Mesothelioma, characterized by its unique complex TME, is a highly refractory cancer type for which no effective targeted therapy exists. uPARAP has been shown to be expressed across all subtypes of mesothelioma, especially in the sarcomatoid and biphasic subtypes, suggesting that a uPARAP-targeted therapy may benefit a specific patient population. In this study, we utilized an antibody–drug conjugate (ADC) comprising an anti-uPARAP mAb conjugated to monomethyl auristatin E via a protease-sensitive linker for preclinical studies on mesothelioma treatment. Using mouse xenograft models with a human mesothelioma cell line or a patient-derived mesothelioma cell isolate, we demonstrated a strong anticancer effect following treatment with the uPARAP-targeting ADC. IHC studies revealed this to be the case, even in tumors exhibiting a heterogeneous expression of uPARAP, suggesting that uPARAP-expressing cancer-associated fibroblasts also play a role in the anticancer effect through a bystander mechanism. Furthermore, we show that combination treatment with cisplatin, commonly used in first-line mesothelioma therapy, leads to a strongly enhanced anticancer effect relative to treatment with either drug alone. Our study demonstrates the potential utility of a uPARAP-targeted ADC as a therapeutic option for mesothelioma, alone or in combination with chemotherapeutics. This perspective is particularly emphasized by a recently initiated clinical trial with a humanized anti-uPARAP ADC for the treatment of other malignancies.Significance:This study highlights the translational promise of a uPARAP-targeted ADC for the treatment of mesothelioma, a cancer lacking effective therapies. Demonstrating potent preclinical efficacy and synergy with cisplatin, our findings support the clinical advancement of a uPARAP-directed ADC strategy, particularly considering an ongoing clinical trial evaluating this approach in other malignancies.

Background Cancer-associated fibroblasts (CAFs) are key drivers of tumor progression in bladder cancer (BLCA), yet their molecular heterogeneity and prognostic utility remain incompletely characterized. Single-cell studies have revealed distinct CAF subpopulations with divergent clinical impacts, necessitating refined prognostic frameworks that capture CAF-mediated progression. Methods We analyzed single-cell RNA sequencing data (GSE267718) from 8 BLCA patients to identify CAF populations and define progression-associated gene signatures. Using 359 TCGA-BLCA samples as the training cohort, we performed non-negative matrix factorization (NMF) consensus clustering on 85 prognostically significant CAF genes, identifying two molecular clusters with distinct survival outcomes. Through LASSO-Cox regression and stepwise selection, we constructed a four-gene Tumor-Progressing Fibroblast Riskscore model comprising FOXA1 , TBX3 , LRIG1 , and RNF11 . Model performance was validated in the E-MTAB-4321 cohort (n = 476). Functional validation of RNF11 was performed using shRNA-mediated knockdown in T24 and 5637 bladder cancer cell lines, followed by proliferation, migration, invasion assays, and transcriptomic profiling. Results Single-cell analysis identified 557 differentially expressed genes between non-muscle-invasive bladder cancer and muscle-invasive bladder cancer CAFs. NMF clustering stratified TCGA patients into 2 clusters with significantly different overall survival. The TPFR model showed consistent prognostic performance in both training and validation cohorts, with high-risk patients showing significantly worse survival. Functional enrichment analysis revealed that TPFR scores correlated with ECM-receptor interaction, focal adhesion, and cytoskeletal regulation pathways. Stratified analysis revealed superior model performance in elderly (>60 years), male, and early-stage patients. In particular, RNF11 knockdown significantly reduced proliferation, migration, and invasion in 5637 and T24 cells, while transcriptomic analysis revealed alterations in tumors after RNF11 knockdown including TNF and MAPK signaling pathway, indicating a potential mechanism by which RNF11 regulates bladder cancer progression. Conclusion We established a CAF-based prognostic model that integrates single-cell insights with bulk transcriptomics for robust risk stratification in BLCA. The TPFR model shows clinical utility particularly in elderly and early-stage patients. Functional characterization showed that RNF11 regulates proliferation and migration of bladder cancer. These findings highlight the prognostic value of CAF signatures and provide a framework for precision medicine approaches in bladder cancer management.

Interleukin-6 (IL-6) plays a pivotal regulatory role in prostate cancer progression, contributing to therapy resistance and reshaping of the tumor microenvironment. This review outlines the clinical relevance of IL-6 as a potential prognostic biomarker and describes its mechanistic involvement in the development of castration resistance, with emphasis on its interplay with distinct cancer-associated fibroblast (CAF) subtypes. Elevated serum IL-6 levels in metastatic castration-resistant prostate cancer are associated with poor responses to docetaxel, enzalutamide, or abiraterone, and correlate with worse prognosis. Mechanistically, IL-6 promotes neuroendocrine differentiation and sustains cell survival under therapeutic stress through activation of signal transducer and activator of transcription 3 (STAT3), mitogen-activated protein kinase (MAPK), and androgen receptor signaling pathways. Recent single-cell studies reveal that prostate CAFs are highly heterogeneous. Certain subtypes are linked to extracellular matrix remodeling and fibrosis, while others exhibit inflammatory or immune-modulatory characteristics, differentially influencing tumor evolution. Specific CAF subsets have been strongly implicated in promoting castration resistance and adverse outcomes. Therapeutic strategies targeting the IL-6/IL-6R axis—such as neutralizing antibodies, advanced chimeric antigen receptor (CAR)-T designs, and combination regimens—are under active investigation. Simultaneously, modulating CAF plasticity to convert tumor-promoting phenotypes into tumor-restraining ones represents a promising therapeutic avenue. A deeper understanding of IL-6 functions across CAF subtypes may unlock novel precision therapy opportunities for prostate cancer.

Single-cell screens identify ADAM12 as a fibroblast checkpoint impeding anti-tumor immunity.

Background/Objectives: Cancer-associated fibroblasts (CAFs) are key stromal mediators of breast tumor progression and therapy resistance. Carvacrol, a dietary monoterpenic phenol, exhibits antiproliferative activity in cancer cells, but its effects on primary human breast CAFs remain unclear. This study aimed to determine whether carvacrol selectively induces mitochondria-related apoptotic signaling in breast CAFs while sparing normal fibroblasts (NFs). Methods: Primary fibroblast cultures were established from invasive ductal carcinoma tissues (CAFs, n = 9) and nonmalignant breast tissues (NFs, n = 5) and validated by α-SMA and FAP immunofluorescence. Cells were exposed to 400 μM carvacrol. Apoptosis was assessed by TUNEL assay and BAX/BCL-XL Western blotting. Changes in signaling pathways were evaluated by analyzing PPARα/NF-κB, sirtuin (SIRT1, SIRT3), autophagy-related markers (LAMP2A, p62), and matrix metalloproteinases (MMP-2, MMP-3). In silico molecular docking and 100-ns molecular dynamics simulations were performed to examine interactions between carvacrol and caspase-3 and caspase-9. Results: Carvacrol induced a pronounced, time-dependent apoptotic response in CAFs, with TUNEL-based viability declining to approximately 10% of control levels by 12 h and a marked increase in the BAX/BCL-XL ratio. In contrast, NFs exhibited minimal TUNEL positivity and no significant change in BAX/BCL-XL. In CAFs, but not NFs, carvacrol reduced PPARα expression and NF-κB nuclear localization, increased SIRT1 and SIRT3 levels, selectively suppressed MMP-3 while partially normalizing MMP-2, and altered autophagy-related markers (decreased LAMP2A and accumulation of p62), consistent with autophagic stress and possible impairment of autophagic flux. Computational analyses revealed stable carvacrol binding to caspase-3 and caspase-9 with modest stabilization of active-site loops, supporting caspase-dependent, mitochondria-related apoptosis. Conclusions: Carvacrol selectively targets breast cancer-associated fibroblasts by inducing mitochondria-related apoptotic signaling while largely sparing normal fibroblasts. This effect is accompanied by coordinated modulation of PPARα/NF-κB, sirtuin, autophagy, and MMP pathways. These findings support further evaluation of carvacrol as a microenvironment-directed adjunct in breast cancer therapy.

LIFR antagonism reverses epithelial pro-CAF programs in pancreatic ductal adenocarcinoma.

Senescent cells have been recognized to play major roles in tumor progression and are nowadays included in the hallmarks of cancer. Our work aims to develop a mathematical model capable of capturing a pro-invasion effect of senescent fibroblasts located in the conjunctive tissue. We focus in the present article on the first moments of the invasion cascade. Considering a localized epithelial tumor, we model the digestion of the collagen fibers of the basement membrane by the proteolytic enzyme MMP-2. The activation of MMP-2 is modelled in detail, as MT1-MMPs bound to the surface of tumor cells interact with proMMPs and TIMPs, proteins enriched in the secretome of senescent Cancer-Associated Fibroblasts, along with its inhibition by TIMPs. Using numerical simulations of the model, calibrated via an extensive literature search, reproducing biologically relevant scenarios, we test the model’s suitability to investigate the effect on basement membrane digestion of fibroblasts presenting a senescence-associated secretory phenotype. Via model reduction, steady state and global sensitivity analyses, we identify the most influential parameters in view of their calibration with empirical data. We conclude the paper discussing mathematical and interdisciplinary perspectives.

Abstract Dermatofibrosarcoma protuberans (DFSP) is the most common cutaneous sarcoma and is defined by chromosomal translocations, high level PDGF signaling, and a characteristic fibroblastic phenotype. The most common translocation is t(17;22) encoding the fusion protein COL1A1::PDGFB. DFSP demonstrates significant local invasion and recurrence, yet little is known about how the local tumor microenvironment impacts its behavior. In particular, it is unclear if DFSP harbors separate populations of non-fusion-harboring fibroblasts among tumor cells. Cancer-associated fibroblasts (CAFs) are well-described in other malignancies and regulate tumor behavior including growth, invasion, and immune responses. The presence and role of non-fusion-bearing fibroblasts and/or CAFs in DFSP is unknown, likely in part due to the overlapping phenotypes of DFSP and fibroblasts, making the ability to distinguish distinct populations more challenging. Here, we sought to further investigate the fibroblastic phenotype of DFSP and the possibility of associated CAFs by enriching for fibroblastic cells in tissue culture, and then comparing transcriptomes to human DFSP tumors and normal human fibroblasts. Fibroblastic outgrowths from primary DFSP tumors were enriched by culturing tumor specimens in media containing DMEM and 10% FBS. We found primary tumors harbored COL1A1::PDGFB fusions, but after 2-4 passages in tissue culture, the COL1A1::PDGFB fusion transcript was undetectable in cultured cells by RNA sequencing or PCR. Cultures demonstrated homogenous spindle cell morphology. Bulk RNA sequencing revealed that cultured cells resembled normal human fibroblasts more closely than their corresponding primary DFSP tumors, implicating a selective growth advantage of non-fusion-bearing cells in culture. These cells, which we termed CAFs, revealed differences from both primary DFSP tumors and normal human fibroblasts. Whereas primary DFSP tumors expressed fusion transcript and strong expression of DFSP markers CD34, PDGFB, NES, and APOD, cultured CAFs demonstrated low expression of typical DFSP markers but significantly elevated levels of fibroblast markers VIM, THY1 (CD90), SMA, and FN1 relative to their primary tumors, with the caveat that more tissue-matched specimens are needed to confirm these findings. Further, we identified elevated expression of several genes in CAFs encoding secreted factors including FGF5, DKK1, and IL6. Taken together, these studies reveal that in addition to higher expression of typical fibroblast markers than primary DFSP tumor cells, CAFs may express secreted factors that may influence DFSP tumor cell behavior through a paracrine mechanism. Further studies are ongoing to validate and define the specificity and biologic significance of these expression profiles in the tumor microenvironment, and will serve to provide new insights into local signaling that occurs in this invasive and highly recurrent malignancy. Citation Format: Jawad Aqeel, Olena Kondrachuk, Talha A. Syed, Claire E. Holtz, Kelly L. Harms, Christina V. Angeles, Andrzej A. Dlugosz, Elisabeth A. Pedersen. Investigating the fibroblastic phenotype of dermatofibrosarcoma protuberans in primary tumors and non-fusion-bearing fibroblasts [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Fusion-Positive Cancer: From Discovery to Therapy; 2026 Jan 13-15; Philadelphia PA. Philadelphia (PA): AACR; Cancer Res 2026;86(1_Suppl):Abstract nr A018.

Neoadjuvant therapy (NAT) is increasingly used for pancreatic ductal adenocarcinoma (PDAC); yet most patients only achieve partial response. Pathological treatment response grading focuses on assessing residual tumor burden, often overlooking changes in tumor microenvironment (TME). To address this gap, we compared tumor cells and TME of 13 NAT-naïve and 23 post-NAT PDACs using integrated spatial pathomics and transcriptomics, with validation in an independent single-cell spatial dataset. NAT significantly reduced tumor burden (14.7%-6.2%, p = 0.004), but systemic comparison of 13 cytomorphometric features of tumor cells alone did not reliably distinguish between naïve and NAT cases. In contrast, NAT profoundly remodeled TME by increasing cancer-associated fibroblast (CAF) and CD8+ T cell densities, promoting CD8+ T cell-tumor cell proximity and fibrosis, reducing tumor-associated neutrophils, and redistributing tertiary lymphoid structures (TLSs). Spatial transcriptomics shows NAT induced apoptosis, DNA-damage response, and AGC-kinase (S_TK_X) signaling in tumor cells, and upregulated complement pathway, p53 signaling, and cellular senescence program in TME. Cross-platform single-cell spatial analysis revealed decreased regulatory T cells (Treg) and a shift from myofibroblastic (mCAF) to inflammatory CAF (iCAF). Importantly, post-NAT patients with more fibrosis had longer overall survival (p = 0.02), and higher B-cell density showed a favorable trend (p = 0.06). Together, these results suggest that beyond tumor debulking, NAT induces a coordinated TME remodeling characterized by fibroblast reprogramming, matrix fibrosis, and immune spatial reorganization. Incorporating assessment of NAT-induced stromal and immune changes into TRG may improve prognostication and guide more precise therapy in post-NAT PDAC.

Adoptive T-cell therapies have shown limited efficacy against solid tumors, so new approaches are required. In this issue, Chantzoura and colleagues describe MiNK-215, a novel allogeneic fibroblast activation protein-targeting chimeric antigen receptor invariant NK T-cell therapy engineered to secrete IL15. They show that it can remodel the tumor microenvironment and enhance antitumor immunity by depleting fibroblast activation protein-positive cancer-associated fibroblasts and activating multiple immune cell types. In mouse lung tumor and human organoid models, MiNK-215 promotes durable, antigen-specific T-cell responses and overcomes resistance to immunotherapy without causing off-target toxicity. See related article by Chantzoura et al., p. XX .