Citations

Abstract Background: Pancreatic ductal adenocarcinoma (PDAC) is driven predominantly by oncogenic KRAS signaling and characterized by an immunosuppressive, fibrotic tumor microenvironment that limits therapeutic responses. RMC-6236, a pan-KRAS inhibitor, and ONIOYID, an investigational anti-tumor agent, each demonstrate partial activity in KRAS-mutant cancers. However, their combined therapeutic potential in PDAC remains unexplored. Here, we evaluated the anti-tumor efficacy, survival benefit, and immunomodulatory effects of RMC-6236, ONIOYID and irinotecan alone and dual combinations multiple in vitro and in vivo PDAC models. Methods: In vitro cytotoxicity assays were performed using KPC, PANC-1, AsPC-1, and PANC-02 cell lines. In vivo therapeutic studies were conducted in orthotopic KPC and PANC-1 tumor models. RMC-6236 was administered orally at 10 mg/kg; ONIOYID and irinotecan was administered intravenously at 5 mg/kg. Tumor growth inhibition, survival, collagen deposition, and immune cell infiltration were analyzed. Tumor microenvironment remodeling was quantified via immunohistochemistry for CD8, CD4, collagen I, and fibronectin. Results: The combination of RMC-6236 and ONIOYID elicited potent anti-tumor effects across all evaluated PDAC cell lines, achieving greater than 90% growth inhibition in vitro. In vivo, co-treatment resulted in more than 90% tumor regression in both KPC and PANC-1 xenograft models, markedly surpassing the efficacy of individual monotherapies and other dual-agent controls. Combination therapy significantly extended overall survival and produced sustained suppression of tumor progression. Mechanistic analyses revealed a substantial reduction in collagen and fibronectin deposition within the tumor microenvironment, consistent with attenuation of desmoplasia. Immune profiling demonstrated a robust enhancement of intratumoral CD8+ and CD4+ T-cell infiltration, along with a pronounced decrease in survivin expression. Importantly, no observable systemic toxicity was detected in treated animals. Conclusions: RMC-6236 combined with ONIOYID yields synergistic anti-tumor effects, remodels the fibrotic PDAC microenvironment, enhances T-cell infiltration, and significantly improves survival in aggressive pancreatic tumor models. These findings provide strong rationale for clinical evaluation of RMC-6236-based combination therapies for KRAS driven PDAC. Citation Format: Hari Krishnareddy Rachamala, Fang Wei, Debabrata Mukhopadhyay, Hani M. Babiker. Combined KRAS pathway inhibition and ONIOYID treatment enhances tumor regression, attenuates desmoplasia, and augments T cell infiltration in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 5842.

Abstract Background: Patients with residual invasive disease after neoadjuvant chemotherapy (NAC) for HER2-positive breast cancer remain at high risk for recurrence even with standard adjuvant trastuzumab emtansine (T-DM1). H2NVAC, a multi-epitope HER2 peptide vaccine, has previously demonstrated the ability to elicit robust and durable immune responses. Here, we assessed the safety and early immunogenicity of H2NVAC in combination with T-DM1 in this high-risk population. Methods: Patients with stage II-III HER2-positive breast cancer and residual invasive disease following NAC and HER2-directed therapy received standard adjuvant T-DM1 alongside six priming doses of H2NVAC administered every 3 weeks. The primary endpoint was the occurrence of dose-limiting toxicity (DLT) within 21 days of the first vaccination, with adverse events graded per CTCAE v5.0. Immunogenicity assessments included HER2-specific T-cell responses measured by IFNγ ELISpot and HER-specific serum antibodies measured by ELISA at baseline and 30 days after the sixth priming dose. Results: 20 patients were enrolled. H2NVAC plus T-DM1 was well tolerated with no DLTs observed. All treatment-emergent AEs were grade 1-2, with fatigue (grade 1 60%, grade 2 5%), peripheral sensory neuropathy (grade 1 35%, grade 2 10%), elevated alkaline phosphatase (grade 1 40%), nausea (grade 1 35%, grade 2 5%), arthralgia (grade 1 30%), and injection-site reactions (grade 1 50%) being most common. Robust vaccine-specific T-cell responses by ELISpot were observed in 94% of evaluable patients, who mounted HER2-specific T-cell responses at 30 days after the sixth priming dose, with a mean 197-fold increase over baseline. Further CYTOF analysis showed a significant decrease in exhausted T-cell phenotypes, with reduced LAG3 and TIM3 expression on both CD4+ and CD8+ T cells. For antibody responses by ELISA, 26% of patients developed HER2 protein-specific antibody responses at this time point. There was no significant increase in antibodies to H2NVAC peptides or to unrelated tumor antigens (p53, IGFBP2, TERT, myoglobin) at 30 days after the sixth vaccine. Ongoing correlative analyses will assess the evolution of immune responses at later time points following completion of T-DM1 therapy. Conclusions: Concurrent administration of H2NVAC with T-DM1 was safe and did not increase toxicity beyond single-agent T-DM1. To our knowledge, this is the first study to demonstrate that a cancer vaccine can be delivered concurrently with an antibody-drug conjugate without increasing adverse effects while still eliciting robust T-cell responses. Ongoing analyses will further define the kinetics and durability of vaccine-induced antibody and T-cell responses at later time points, as well as evaluate the efficacy of H2NVAC in reducing recurrence risk in the randomized phase 2 trial. Citation Format: Saranya Chumsri, Sharmila Giri, Andy J. Ness, David W. Hillman, Nadine Norton, Davitte Cogen, Brian M. Necela, Aziza Nassar, Donald W. Northfelt, Pooja Advani, Rohit Rao, Alvaro Mareno-Aspitia, Brenda Ernst, Kathryn J. Ruddy, Matthew P. Goetz, Keith L. Knutson. Safety, tolerability, and early immune responses in the safety run-in of an HER2 multi-epitope vaccine combined with T-DM1 in residual HER2-positive breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 6715.

Abstract Background: Clear cell renal cell carcinoma (ccRCC), metastatic castration-resistant prostate cancer (mCRPC), and glioblastoma (GBM) are treatment-refractory tumors marked by high TGF-β1, a master suppressor of antitumor immunity and antigen presentation. Pharmacologic methylseleninic acid (MSA) potently inhibits TGF-β1, PD-L1, and VEGF without significant off-target toxicity. FN14, the TWEAK receptor and a metastasis driver, is selectively overexpressed in these malignancies, making it a high-specificity CAR-T target. Methods: We developed second-generation anti-FN14 CARs with CD28 or 4-1BB costimulation and CD3ζ signaling and lentivirally transduced them into human CD4+/CD8+ T cells. Cytotoxicity against FN14+ ccRCC, mCRPC, GBM lines and patient-derived tumors was measured using LDH release and xCELLigence assays. Effector function was assessed by intracellular cytokines, phenotyping, and multiplex analysis. MSA was tested at physiologic concentrations to evaluate effects on CAR-T viability, metabolism, function, and tumor susceptibility. Results: Anti-FN14 CAR-T cells mediated rapid, antigen-specific lysis across all tumor types, achieving >50% specific lysis at an E:T ratio of 1:1. MSA (2.5-5 µM) reduced tumor PD-L1 and TGF-β by >40% and improved CAR-T metabolic activity, enhancing IL-2 and IFN-γ secretion. Manufacturing CAR-T cells with MSA (2.5 µM) increased cytotoxicity and persistence versus controls (p < 0.01). MSA’s effects were dose- and schedule-dependent at clinically compatible concentrations without detectable off-target toxicity. Conclusion: MSA augments anti-FN14 CAR-T cytotoxicity, metabolic fitness, and sustained effector function by suppressing tumor-derived TGF-β1 and PD-L1 and directly enhancing CAR-T activity. As a clinically relevant TGF-β1 inhibitor and active seleno-L-methionine metabolite, MSA represents a readily translatable strategy to reduce CAR-T exhaustion and improve efficacy in TGF-β-rich solid tumors. Citation Format: Gloria B. Kim, Obed B. Amissah, Casey R. Ager, Yousef Zakharia, Youcef M. Rustum. Methylseleninic acid enhances anti-FN14 CAR-T cell effector function and redirects cytotoxicity against TGF-β-rich kidney, prostate, and brain tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 6496.

Abstract Background: Cellular immunotherapy has transformed cancer treatment, but success in solid tumors remains limited by long manufacturing times, high costs, and the need for viral vectors that permanently modify DNA. To address this, we examined electroporation (EP) and mechanoporation (MP) approach to transfect T cells with mRNA to enable the development of a bedside immune cell editing platform. NKG7, natural killer cell granule-7, was previously demonstrated to play key function in activating T-cell cytotoxicity function. mRNA transfection of T cells with NKG-7 can increase these cells’ anti-tumor cell killing. We examine EP and MP methods for NKG7 transfection in primary peripheral blood mononuclear cells (PBMCs) from healthy donors. Method: Synthetic Clean Cap mRNAs encoding NKG7 or NKG7 with membrane-bound cRNA IL-2 were introduced into PBMCs by electroporation (MaxCyte) or mechanoporation (Portal Bio). T cell expression of NKG7 and IL-2 were analyzed by CytoFlex flow and Kaluza. Result: The yield at EP and MP were comparable at 0.615+/-0.09% and 0.597+/-0.16%, respectively. Viability were high at above 80% for 3 days after EP and MP. NKG7 and NKG7+cIL-2 mRNA transfection led to different NKG7 expression kinetics in T-cells and between EP and MP. With EP, CD4 T-cells showed an increase in NKG7 expressions with the highest MFI ratio (NKG7 MFI/ IgG MFI) compared to mock EP at Day 1 for the NKG7 -only EP (1.25 ± 0.38) and at Day 2 for NKG7+cIL-2 EP (1.20 ± 0.27). CD8+ T cells displayed a similar trend, with peak NKG7 expression at Day 1 for NKG7 EP (1.22 ± 0.76) and Day 2 for NKG7+cIL-2 EP (1.21 ± 0.90). However, MP did not enhance NKG7 expression in CD4+ T cells. NKG7 expression peaked at Day 1 for both NKG7 (1.28 ± 0.42) and NKG7 + cIL-2 (1.24 ± 0.20). IL2 expression peaked at Day 1 for both EP and MP: EP, CD4+ T (91.5% ± 4.4), CD8+ T (92.7% ± 12.8); MP, CD4+ T (88.9% ± 31.7), CD8+ T (84.7% ± 9.6). Functional assays for anti-tumor cell killing of these transfected cells are currently ongoing. Conclusions: We report that EP of PBMC can transfect all cell populations. MP may yield comparable yield, viability and NKG7 expression in CD8 T cells compared to EP, but without the need to isolate CD8 T cells from PBMC. EP and MP method can be used for bedside immune cell transfection depending on the target and cell populations of interest. Citation Format: Chen Wu, Christoph Schaefers, Malvika Gupta, Kevin Regan, Zuoyi Shao, Andre De Menezes Silva Corraes, Virginia Van Keulen, Jacob Hirdler, Tobias Peikert, Timothy D. Wiltshire, Haidong Dong, Yi Lin. A non-viral mRNA engineering platform for rapid, same-day immune-cell therapies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 5198.

Abstract Several allogeneic CAR T-cell therapies are in clinical trials to evaluate safety, many of which rely on CRISPR/Cas-based genome editing. However, the Cas enzyme’s random repair mechanism elevates the risk of undesired, off-target effects, posing a challenge for safe allogeneic CAR T-cell generation. To mitigate the risk of therapy-related oncogenesis, we sought to pursue an alternative safe strategy to manufacture allogeneic CAR T-cells distinct from the preexisting ones in the clinic. We have developed a CRISPR RNA (crRNA) targeting T-cell receptor beta constant (TRBC) gene, which in conjunction with AsCas12a Ultra enzyme, causes site-specific editing by eliciting a predictable microhomology-mediated end joining (MMEJ) DNA repair pathway, which mitigates off-targeting risk. Targeted amplicon sequencing was employed to evaluate off-targeting and repair mechanisms. Graft versus host alloreactivity as well as CAR T persistence was evaluated using immunocompromised mice. In vivo tumor challenge study was conducted for over 3 months. Engraftment confirmation was done using immunohistochemistry and flow cytometry. Interestingly while evaluating the edited T-cells, we sequestered a unique T-cell population that showed TCR disruption yet remained CD3-positive and did not cause in vivo alloreactivity. These CD3-Retained, Allogeneically Functioning T-cells (CRAFT-cells) showed a similar growth rate as unedited T-cells and were then used as a platform to produce CD19-targeted CAR T-cells and BAFF-R-targeted CAR T-cells. When compared to the standard CD3-disrupted allogeneic CAR T-cells, CRAFT CAR T-cells displayed an equally robust cytotoxicity while possessing a safer genomic profile. CRAFT CAR T-cells could function as effector cells for bispecific T-cell engager (BiTE) and induce CD3-dependent cytotoxicity against tumor cells. Pertinently, CRAFT CAR T-cells as opposed to CD3-disrupted CAR T-cells, were present in mouse xenografts without alloreactivity. Having the onset of MMEJ-directed repair and minimal off-targeting, positions this CRAFT crRNA to generate safer allogeneic CAR T-cells with an overall reduced genotoxic profile in a clinical setting. This unique CRAFT CAR T-cell population displays in vivo persistence. Additionally, CRAFT CAR T can be combined with BiTE therapy, offering a promising and potentially more durable alternative to preexisting ex vivo allogeneic CAR T-cell therapies. Citation Format: Tanya Hundal, Yan Luo, Yaqing Qie, Martha E. Gadd, Shaohua Guo, Mohamed A. Kharfan-Dabaja, Hong Qin. CD3-positive allogeneic CAR T-cells: A novel platform with persistence, BiTE-capture, and no alloreactivity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 4283.

Abstract Introduction: Lung cancer rates differ across rural and urban areas, but few studies have evaluated rural-urban differences across the risk-screening continuum. We examined smoking, cessation interventions, and lung cancer screening patterns across the rural-urban continuum in a geographically defined area over 10 years. Materials and Methods: A retrospective cohort study (2014-2023) was conducted using clinical data from the Rochester Epidemiology Project, derived from healthcare encounters in a 27-county region of the midwestern United States. Patients ages 40-80 were included. We used Rural-Urban Commuting Area codes to assign residence as urban, rural, or highly rural. We examined yearly smoking prevalence, cessation intervention (pharmacotherapy, counseling), and low-dose computed tomography (LDCT) lung cancer screening. Results: Over the 10-year study period, the sample size ranged from 305,530 to 340,411 people annually with 36-38% urban, 56-57% rural, and 6-7% highly rural. Current smoking prevalence declined from 14 to 12% over the 10-year period (range=12-16%; p=0.06) and was consistently lower in urban areas (range=10-14%) than rural (range=12-17.0%) and highly rural areas (range=12-18%; p=<0.001). Among individuals who currently smoked with no history of lung cancer, yearly smoking cessation intervention ranged from 16% to 23%, increasing over the 10-year period (p=<0.001). Cessation medication (varenicline, bupropion, or nicotine replacement) prescription consistently increased overall over time but remained higher in urban than rural and highly rural areas (p=<0.001). Cessation counseling rates also increased overall over time and were similar between urban and rural areas and lower in highly rural areas (p=<0.001). Among people who had ever-smoked aged 50-80 years with no diagnosis of lung cancer, LDCT screening increased from 0.0% to 3.1% over the study period. Increases were higher in urban areas (0.0-3.6%) and similar in rural and highly rural areas (0.0-2.8% and 0.0-2.9%, respectively; p=<0.001). Among people who currently smoked, LDCT screening also increased over the study period (0.0-6.4%), with higher increases in urban (0.1-8.0%) than rural (0.0-5.7%) or highly rural (0.1-6.1%) areas (p=<0.001). After the new screening guidelines in 2021, rates in all areas increased year-on-year. Conclusion: In this cohort, we found that smoking prevalence, cessation interventions, and lung cancer screening improved from 2014-2023 across the rural-urban continuum. Unfortunately, smoking prevalence remained higher and cessation interventions and screening rates lower in rural compared to urban areas. The persistent patterns underscore the need for strategies to overcome barriers for rural residents and improve lung cancer prevention and early detection in all areas. Citation Format: Brianna Tranby, Paul A. Decker, Jiang Ruoxiang, David Midthun, Lori C. Sakoda, Melinda C. Aldrich, Debra Friedman, Adoma Manful, Oindrila Bhattacharyya, Christi Patten, Chyke A. Doubeni. Patterns of tobacco use, cessation interventions, and lung cancer screening in rural vs. urban areas over time; a 10-year retrospective cohort study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 5045.

Abstract Background: Early-onset gastrointestinal (GI) cancers are increasing globally, yet the genomic basis for age-related differences across multiple tumor types remains poorly defined. We leveraged AACR Project GENIE v18.0 (N≈34,000 GI tumors) to characterize molecular distinctions by age in colorectal, pancreatic, small bowel, and anal cancers with sufficient early-onset representation. Methods: Clinical and genomic data were extracted and tumors classified into early-onset (<50 years) and late-onset (≥50 years). Mutation frequencies were compared by cancer type and age group, focusing on recurrent drivers, DNA repair, Wnt signaling, RAS/MAPK, chromatin remodeling genes, and targetable alterations. Results: Early-onset colorectal cancer (N=5,724) showed increased Wnt/β-catenin pathway alterations: APC (+4.9%), TCF7L2 (+4.1%), and TP53 (+5.0%), while late-onset tumors (N=15,807) were enriched for BRAF (−5.4%), RNF43 (−1.9%), and GNAS (−1.1%), indicating divergent tumorigenic pathways. Early-onset pancreatic cancer (N=890) exhibited significantly lower frequencies of canonical drivers—KRAS (−24.7%), TP53 (−15.6%), CDKN2A (−6.9%), SMAD4 (−6.0%)—with enrichment of MEN1 (+3.5%), TSC2 (+3.0%), ATRX (+2.0%), DAXX (+1.9%), and CTNNB1 (+2.4%), consistent with fusion-driven, hereditary, and chromatin remodeling biology. Small bowel cancer (N=99) in early-onset patients demonstrated enrichment in DNA damage response and MAPK/RAS genes including BRCA2 (+7.2%), NF1 (+7.4%), FBXW7 (+8.8%), FLT4 (+6.5%), ARAF (+6.4%), and ALK (+5.1%), whereas late-onset tumors (N=538) were enriched for KDR (−5.1%) and MGA (−5.2%). Early-onset anal cancer (N=62) showed elevated MGA (+7.8%), WHSC1/NSD2 (+6.9%), PBRM1 (+6.2%), FANCA (+5.2%), ERCC5 (+6.2%), and MSH6 (+5.9%), highlighting chromatin remodeling and DNA repair pathways potentially related to HPV biology; late-onset tumors (N=464) had enrichment in ATM (−5.6%), PTEN (−5.5%), STK11 (−5.2%), APC (−5.2%), and KMT2C (−5.0%), reflecting age-associated genomic instability. Conclusions: This pan-GI age-stratified analysis reveals distinctive oncogenic programs in early-onset GI cancers characterized by Wnt/TP53-driven colorectal, fusion- and chromatin remodeling-driven pancreatic, DNA damage response/MAPK-driven small bowel, and chromatin-immune DDR signatures in anal cancers. These findings underscore the need for age-tailored precision oncology and support routine genomic profiling in early-onset GI malignancies to identify targetable alterations enriched in younger patients. Citation: AACR Project GENIE Consortium. AACR Project GENIE: Powering Precision Medicine Through an International Consortium. Cancer Discov. 2017;7(8):818-831. (Data: GENIE Release 18.0-public)Acknowledgement: AACR and Project GENIE registry Citation Format: Ahmed Abdelhakeem, Nency Ganatra, Dina Elantably, Tayo Adeoye, Nayef H. Abdel-Razeq, Mosalem M. Osama, Hani M. Babiker. Distinct age associated genomic landscapes in colorectal, pancreatic, small bowel, and anal cancers: A pan gastrointestinal analysis of 34,000 tumors from AACR Project GENIE v18.0 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 4105.

Abstract Background: Epidemiologic and other studies have identified environmental, occupational, and genetic risk factors for lymphoid and myeloid malignancies, but most studies have been conducted in Western populations. Investigations in populations with differing exposure patterns, distributions of disease subtypes, and genetic architecture are needed to fully understand hematopoietic tumor etiology. Methods: We conducted a large, multicenter, hospital-based case-control study of lymphoid and myeloid neoplasms in East Asia (AsiaLymph), including 5,671 lymphoid cases, 1,879 myeloid cases, and 3,858 controls. Participants completed a computer-assisted personal interview and provided biospecimens. Cases underwent central pathology review and were coded into the WHO Classification. Herein, we describe the study methods in detail and report association results for education, body mass index, and family history. Results: Greater BMI at age 20 but not at age 40 was associated with odds of total lymphoid neoplasm (per 5 kg/m2 increase: OR [95% CI]: 1.18 [1.09-1.27]), total myeloid neoplasm (OR [95% CI]: 1.17 [1.05-1.29]), and several subtypes. Greater educational attainment was associated with increased odds of total lymphoid neoplasm (for college vs. less than primary education: OR [95% CI]: 1.41 [1.21-1.65]) but not myeloid neoplasm (OR [95% CI]: 1.17 [0.95-1.45]; p-heterogeneity=0.02). There were also positive associations between family history of hematologic cancer in first degree relatives and odds of lymphoid neoplasm (OR [95% CI]: 1.53 [1.15-2.03]) and myeloid neoplasm (OR [95% CI]: 1.65 [1.11-2.44]) and specific subtypes. None of the evaluated risk factors were associated with NK/T-cell lymphoma, which supports a distinct etiology for this subtype. Conclusion: The AsiaLymph Study is one of the largest molecular epidemiology studies of both lymphoid and myeloid neoplasms with standardized World Health Organization classification of histopathologic subtypes and will serve as a valuable resource for etiologic investigations into risk factors for these malignancies. Citation Format: Qing Lan, Lauren M. Hurwitz, John K. Chan, Tai Hing Lam, Kexin Chen, Yok Lam Kwong, Xu Caigang, Brian CH Chiu, Raymond Liang, Ip Dennis, Wei Hu, Bryan Bassig, Mark Purdue, Jun Xu, Sarah Locke, Sophia S. Wang, James R. Cerhan, Sonja Berndt, Jonathan N. Hofmann, Jianxin Shi, Kai Yu, Shahinaz Gadalla, Lisa J. McReynolds, Rena Jones, Hongji Dai, Zhangyan Lyu, Lugui Qiu, Wei Liu, Huilai Zhang, Xianhuo Wang, Lindsay M. Morton, Stephen Chanock, Martha Linet, Melissa C. Friesen, Roel Vermeulen, Nathaniel Rothman. A multi-center hospital-based case-control study of lymphoid and myeloid neoplasms (AsiaLymph): Study design and initial findings for education, body mass index, and family history [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 5051.

Abstract Non-small cell lung cancer (NSCLC) exhibits strikingly different responses to antiangiogenic therapies between its two major histologic subtypes, lung adenocarcinoma (LUAD) and squamous cell carcinoma (LUSC), suggesting an histotype-specific regulation of angiogenesis. Cancer-associated fibroblasts (CAFs) commonly exhibit an activated/myofibroblast-like phenotype in NSCLC, and are emerging as key modulators of tumor progression; however, their contribution to angiogenic control remains undefined. Here, we investigated angiogenesis and hypoxia signatures in NSCLC and integrated bulk RNA-seq, scRNA-seq, CAF secretome profiling, genetic perturbations, and functional in vitro and in vivo assays to dissect the histotype-dependent production of pro-angiogenic factors by CAFs. We observed greater angiogenesis and reduced necrosis/hypoxia in LUAD compared to LUSC across multiple patient cohorts. The LUAD-CAF secretome was primed for angiogenesis through SMAD3-dependent overproduction of key regulators, most notably TIMP-1 and VEGF-A. We also uncovered a previously unrecognized role for TIMP-1 in promoting endothelial hyper-branching. In contrast, LUSC-CAFs displayed attenuated angiogenic activity despite robust HIF-1α upregulation and an hypoxia-associated transcriptional program, due to their epigenetic repression of SMAD3 and compensatory increase in SMAD2. Collectively, these results reveal that CAFs critically shape the distinct angiogenic landscapes of LUAD and LUSC through opposing SMAD2/3 regulation of TIMP-1, VEGF-A, and hypoxia signaling. These results further highlight the therapeutic potential of targeting stromal SMAD3/TIMP-1 in LUAD or microenvironmental stressors such as hypoxia and acidosis in LUSC. In addition, these findings provide a biological framework for understanding histotype-specific patterns of dissemination, immune evasion, and response to antiangiogenic therapies in NSCLC. Citation Format: Jordi Alcaraz, Natalia Isabel Diaz Valdivia, Paula Duch, Marselina Arshakyan, Amelia Parker, Alejandro Bernardo Suarez, Danielle Park, Erik Sahai, Noemi Reguart, Derek C. Radisky, Oriol Casanovas. Antagonistic SMAD2/3 control of TIMP-1, VEGF-A, and hypoxia signaling in myofibroblasts shapes histotype-specific angiogenesis in lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 4797.