Graham, Rondell

TPS160 Background: Up to 50% of patients with gastric cancer (GC) may develop peritoneal metastasis (PM) that is associated with resistance to systemic therapy and poor prognosis. Although cytoreductive surgery and intraperitoneal (IP) chemotherapy were shown to modestly improve the survival of patients with PM from gastric GC (PM-G), these clinical trials were performed in the pre-immunotherapy era. The significant heterogeneity in trial design and patient selection criteria further limit the applicability of these trial results to current clinical practice where anti-PD-1/L1 immunotherapy and/or targeted therapy in combination with chemotherapy have become a common, standard first-line therapy for the majority of patients with metastatic GC, raising the question of whether chemotherapy such as paclitaxel remains the most effective IP therapy. IP therapy using novel immunotherapy such as bispecific antibodies and chimeric antigen receptor T-cell therapy have demonstrated safety and promising antitumor activities in PM-G. We are conducting a phase 1b clinical trial that evaluates the efficacy of IP interleukin-2 (IL-2) in patients with PM-G with stable disease on first-line chemo-immunotherapy based on the hypothesis that IP IL-2 may synergize with intravenous (IV) chemo-immunotherapy to improve the treatment of PM-G. Multi-omics studies using patient blood, peritoneal fluid, and tissue specimens serially collected from this trial will be performed to characterize the changes in the tumor immune microenvironment of PM-G and identify new therapeutic targets. Methods: Patients with PM only from gastric adenocarcinoma are eligible for this phase 1b trial. All participants will continue IV fluorouracil-containing chemotherapy with nivolumab every 2 weeks and concurrently receive up to 16 doses of IP IL-2 (aldesleukin 6 × 10 5 IU/m2) weekly through an indwelling peritoneal catheter (Bard). Diagnostic laparoscopy (DL) will be performed before initiation of IP IL-2 and after 8 doses of IP therapy to assess treatment response based on the peritoneal cancer index (PCI), which is the primary endpoint of the trial. Patients with at least stable radiographic disease will continue to receive another 8 doses of IP IL-2 and undergo a third DL. Secondary endpoints include safety, peritoneal regression grading score, overall survival, and progression-free survival. Major inclusion criteria include mismatch repair-proficient or microsatellite-stable GC, PCI of 3-24, absence of distant metastasis other than PM, stable disease on first-line IV chemo-immunotherapy, tolerability of anti-PD-1 therapy, and adequate organ function. Enrollment began in 2024 and remains active. To date, seven of planned 15 patients have received study treatment without significant treatment-related adverse events and three of these patients underwent curative-intent cytoreductive surgery. Clinical trial information: NCT05802056 .

Abstract Background: Most colorectal cancer (CRC) arises from polyps and is mainly prevented by polypectomy. The most important polyps to manage with colonoscopy are those with highest CRC risk- namely, advanced polyps (> 1cm, villous histology or high-grade dysplasia (HGD). Yet, 48% of advanced polyps recur within 1 to 3 years of removal, and up to 5% of advanced polyps under surveillance still progress to CRC. We performed this pilot study to investigate molecular and microenvironment heterogeneities of polyps and how they might impact their clinical behavior. Methods: GeoMx spatial transcriptomics was performed on FFPE tissues from three different polyp outcome phenotypes (POPs) including the polyp that does not recur (POP-NR), that recurs following polypectomy but cured by colonoscopy (POP-R) or the polyp despite polypectomy develops CRC at the polypectomy(ies) site (POP-CRC). Normal colon and polyp with low or HGD from the index polyp were assessed from 6 patients with POP-NR, 9 with POP-R and 12 with POP-CRC with a minimum of 2 follow up colonoscopies at 3-year intervals. Epithelium was identified as PanCK positive, and stroma identified as PanCK negative and positive nuclear staining. Cell type deconvolution was implemented using single-cell adult human intestinal tract catalogue (Elmentaite et al., https://www.gutcellatlas.org/). Differential gene expression (DEG), cell type abundance and functional enrichment analyses was performed using linear mixed effects model, and observations with p-value < 0.05 and log2FC >= |1| are reported. Results: The greatest number of DEGs were identified in stroma of the index POP-CRC compared to POP-NR polyps (n = 17 down and 11 upregulated genes), followed by epithelium of the index POP-CRC vs POP-NR polyps (n = 10 down and one upregulated gene(s)). Between the index POP-CRC and POP-R, epithelium showed downregulation of 7 genes, and upregulation of no genes. In stroma two genes were down and none upregulated. Four genes were downregulated in stroma of the index POP-R vs POP-NR polyp and 3 in epithelium, and one gene was upregulated in stroma and another in epithelium. MZT2B was upregulated in stroma of both the index POP-R (log2FC = 1.09, p-value = 0.0014) and POP-CRC (log2FC = 1.29, p-value = 0.0001) and has been implicated as a prognostic marker associated with worse prognosis in certain cancers. IgM and IgA plasma cells, proximal progenitors, MMP9+ inflammatory macrophages and myofibroblasts were found to be downregulated in epithelium of index POP-CRC and POP-R compared to POP-NR polyps; while microfold cells were downregulated in stroma of index POP-CRC and POP-R compared to POP-NR polyps. Conclusions: The stromal microenvironment and less so, epithelial features present in the index polyp differ based on a polyp’s future clinical behavior. The polyp-immune interaction warrants further study as a potential prevention target against polyp progression. Citation Format: Mrunal Dehankar, Lisa A. Boardman, Daniel O'Brien, E. Aubrey Thompson, Jennifer M. Kachergus, Ji Shi, Alexej Abyzov, Milovan Suvakov, Rondell P. Graham, Chen Wang. Stromal immune composition significantly contributes to adenomatous polyp recurrence or progression to 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 4018.

Abstract Background: Hepatocellular carcinoma (HCC) is largely refractory to immune checkpoint blockade due to immune exclusion, stromal barriers, and aberrant vasculature. We evaluated whether multimodal therapy - external beam radiotherapy (EBRT) for antigen release, intratumoral dendritic cell (DC) vaccination for antigen presentation, PD-L1 blockade for immune activation, and VEGF inhibition for vascular normalization - could convert “cold” HCC tumors into sustained immune-inflamed states. Methods: Serial biopsies (baseline, post-EBRT, end-of-treatment [EOT], and progression [PD] when available) from three patients enrolled in an ongoing phase II trial (NCT03942328) underwent multiplex immunofluorescence, spatial neighborhood analysis, and transcriptomic profiling. Longitudinal changes in cellular composition, immune-stromal architecture, spatial contact networks, and pathway activity were compared. Results: Baseline tumor microenvironments (TMEs) were strongly immune-excluded, dominated by tumor (PanCK+60-70%) and stroma (SMA+/Vimentin+25-30%) with sparse immune infiltration (<10-15%). Post-therapy, immune complexity and spatial connectivity increased 2-3-fold in all patients. Patient 1 showed robust cold-to-hot conversion with CD8+(3x), CD4+(2.2x), and DC (2.3x) expansion, increased CD8-DC interactions (2.5x), and reduced tumor fraction (-40%). Transcriptomics showed marked upregulation of IFN-γ (↑3.4x), HLA-DRA (↑2.7x), and reductions in VEGFR2 (↓50%) and HIF1A (↓40%), consistent with vascular normalization. Patient 2 exhibited stromal/vascular remodeling and improved T-cell infiltration but restricted immune diversity, with CD4+/CD8+ dyads (↑2.2x) and B/NK cells(↓ 60%). Neighborhood diversity rose (3→7 communities) and immune-tumor proximity improved (distance ↓ 35%). Patient 3 showed transient inflaming with CD8+(↑3x), DC(↑2x), and new CD4-CD20/CD4-CD56 interactions, followed by relapse marked by stromal/myeloid re-expansion (SMA+↑1.8x, CD14+↑2.5x), angiogenic resurgence (VEGFR2/CD34+↑2.2x), contraction of immune networks, and genomic shift from activating CTNNB1 mutation loss to ATM gain. DCs accumulated but localized mainly to DC-DC or DC-myeloid niches, indicating non-productive antigen presentation. Conclusions: Multimodal EBRT+DC+PD-L1/VEGF blockade induces four-sided synergistic TME reprogramming - antigen release, immune priming, checkpoint release, and vascular normalization - promoting cold-to-hot conversion in HCC. Durable inflaming correlates with sustained T-cell/DC expansion and vascular remodeling, whereas relapse reflects stromal/myeloid reinforcement and genomic adaptation. These findings define mechanistic trajectories of TME remodeling and highlight actionable barriers to sustained immunotherapy response in HCC. Citation Format: Lionel Aurelien Kankeu Fonkoua, Christopher L. Hallemeier, Basim Salem, Arina Tkachuk, Kaitlynn McCay, Panwen Wang, Ying Li, Thomas D. Atwell, Krishan R. Jethwa, Caitlin Conboy, Nguyen H. Tran, Leslie A. Washburn, Melody Wu, Chen Wu, Andre De Menezes Silva Corraes, Rondell P. Graham, Jose Caetano Villasboas, Kevin Regan, Zuoyi Shao, Rayaan Kamal, Nathan R. Foster, Haidong Dong, Sean Park, Yi Lin, Lewis R. Roberts. Multimodal immunotherapy remodels the tumor microenvironment in hepatocellular carcinoma: Integrative spatial and transcriptomic profiling from a Phase II trial [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 7935.

Abstract Background: Aberrations in telomere length have important implications in cancer development and progression. This study aimed to determine whether leukocyte telomere length (LTL) in patients with colorectal cancer (CRC) is associated with survival outcomes. We also investigated whether genetic variants in telomere maintenance genes are associated with survival in these patients. Methods: Blood specimens were collected from 1,007 patients prior to receiving chemotherapy or radiation. Genomic DNA was extracted using the Promega Maxwell RSC instrument. LTL was measured in triplicate using monochrome multiplex PCR, where the average amplification value of telomeric repeats was termed T. Similarly, PCR amplification of a single-copy reference gene was performed, and its average amplification value was termed S. The telomere length for each sample was expressed as the T/S ratio. Genotyping of single-nucleotide polymorphisms (SNPs) in TERC, TERT, and OBFC1 genes was conducted at the institutional Genome Analysis Core facility. Kaplan-Meier survival curves were generated to evaluate patient survival outcomes. Results: Younger individuals (∼25 years) exhibited nearly a twofold longer LTL compared with older individuals (∼75 years). No significant difference in LTL was observed between stage II and stage III CRC patients. A strong inverse correlation was observed between patient age and LTL (Spearman’s r = -0.48; p = 1.13 × 10-58). Females had significantly longer LTL than males (p = 3.97 × 10-5). The TERC SNP rs1317082 was significantly associated with both overall survival (OS) and disease-free survival (DFS) in the combined stage II and stage III patient cohort (p = 0.017 and p = 0.023, respectively). Similarly, the OBFC1 SNP rs9419958 was significantly associated with OS (p = 0.016). Importantly, LTL itself was significantly associated with both OS and DFS (p = 0.008 and p = 0.044, respectively) among the combined stage II and stage III patients. Kaplan-Meier survival analyses demonstrated that age- and sex-adjusted LTL was predictive of long-term survival outcomes. Conclusions: Survival among patients with stage II and III colorectal cancer is significantly influenced by LTL. Additionally, specific allelic variants of telomere maintenance genes, including TERC and OBFC1, are independently associated with improved survival, irrespective of LTL. These findings suggest that peripheral blood LTL measurement, along with telomere-related genotyping, may serve as a valuable prognostic marker for colorectal cancer outcomes. Funding: Individualizing colorectal cancer patient care using the host and tumor telomere phenotype (RO1 CA204013), Curtiss Fund (92541775), C-SiG Core(s): Epigenomics & Spatial Biology Core, and Clinical Core of the Mayo Clinic Center for Cell Signaling in Gastroenterology (P30DK084567) Citation Format: Estela M. Cruz Garcia, Gobinda Sarkar, Jun Chen, Shubham Sood, Kim Kossick, Daniel Schupack, Rondell Graham, Brooke Druliner, Zahra Heydari, Lauren Helgeson, Richard G. Cawthon, Lisa A. Boardman. Longer leukocyte telomeres and specific alleles of telomere maintenance genes are independently associated with improved survival of colon cancer patients [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 1919.

Abstract Background: Spatial cellular ecosystems in the tumor microenvironment (TME) form dynamic signaling hubs that critically influence cancer disease progression and response to therapy, including response to immune checkpoint inhibitors (ICIs). However, tumor sampling bias and the impracticality of acquiring serial tumor biopsies have made it challenging to profile the TME clinically. To address this challenge, we developed Liquid EcoTyper, a multi-analyte AI framework to quantify TME spatial cellular ecosystems—termed spatial ecotypes (SEs)—noninvasively from cell-free DNA (cfDNA) methylation data. Methods: In previous work, we discovered nine spatial ecotypes, including SEs associated with ICI response (e.g., SE7 with benefit, SE4 with resistance), and quantified them from 1,249 bulk tumor RNA-seq profiles of melanoma, non-small cell lung cancer (NSCLC), and bladder cancer (BC) patients (Cancer Res (2025) 85 (8_Supplement_1): 153). Here we trained Liquid EcoTyper, an interpretable deep learning model, to transfer SE profiling to cell-free DNA using CpG methylation profiles. Performance was quantified using simulated and real data, including methylation profiles (EM-seq) of plasma cfDNA paired with tumor biopsy-derived SE levels determined by EM-seq (n=20 pairs) or 10x Visium (n=15 pairs). Clinical outcome prediction was evaluated using pretreatment plasma from patients treated with ICI alone (n=78 melanoma pts), chemotherapy and ICI (n=25 NSCLC pts), and enfortumab vedotin and ICI (n=10 localized muscle-invasive BC (MIBC) pts). Tumor mutational burden (TMB), tumor PD-L1, or circulating tumor DNA (ctDNA) were profiled as a comparator where possible. Results: We observed striking concordance between plasma-derived SE levels and tumor biopsy-confirmed SE levels from the same patients, demonstrating that liquid biopsy analysis of cfDNA methylomes can recapitulate TME spatial biology. Underscoring specificity, no reliable SE signal was detectable from peripheral blood mononuclear cells. In pre-ICI plasma, liquid SE levels were significantly associated with ICI-based response (SE7) versus resistance (SE4) in patients with melanoma, NSCLC, and MIBC, with a mean cross-cancer area under the curve (AUC) of 0.87 for SE7 (range 0.8-0.97) and 0.81 for SE4 (range 0.76-0.85)—far surpassing TMB, tumor PD-L1, and ctDNA in evaluable patients, both in binary analyses of response and multivariable models of survival. Our results also showed potential to predict pathologic complete response in the neoadjuvant setting. Conclusion: Liquid EcoTyper is a scalable noninvasive AI-based framework for spatiotemporal assessment of the TME. By enabling TME-informed risk stratification without surgical biopsies, Liquid EcoTyper has potential to enable more precise and actionable decision making in patients with solid tumors. Citation Format: Erin L. Brown, Wubing Zhang, Abul Usmani, Noah Earland, Ayesha Hashmi, Chibuzor Olelewe, Anushka Viswanathan, Pradeep S. Chauhan, Minji Kang, Chloé B. Steen, Hyun Soo Jeon, Susanna Avagyan, Irfan Alahi, Nicholas P. Semenkovich, Matteo Bergsagel, Janella C. Schwab, Chloe M. Sachs, Faridi Qaium, Peter K. Harris, Antonella Bacchiocchi, Qingyuan Cai, Andrew J. Gentles, Rondell P. Graham, Peter C. Lucas, Ryan C. Fields, Jacob J. Orme, Aaron S. Mansfield, Mario Sznol, Ruth Halaban, David Y. Chen, Aaron M. Newman, Aadel A. Chaudhuri. Liquid biopsy profiling of the tumor microenvironment to determine response to immunotherapy regimens across solid 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 94.