Citations

Abstract High-grade serous ovarian cancer (HGSOC), the most prevalent and lethal ovarian cancer subtype, is typically diagnosed at an advanced stage due to the absence of effective early detection strategies. Mounting evidence indicates that HGSOC originates from the fallopian tube (FT), particularly from secretory epithelial cells in the fimbria. However, incomplete understanding of the cellular and molecular origins of HGSOC continues to hinder early interception efforts. To address this, we established a clinically and genetically annotated living FT organoid biobank at Mayo Clinic, representing over 200 patient donors. Using optimized enrichment protocols, we isolated FT epithelial stem/progenitor cells from tissue and Tao brushings, generating organoids independent of anatomical site or laterality that recapitulate native FT epithelial architecture and lineage differentiation. We applied integrated multi-omic analyses, including single-cell RNA sequencing, single-nucleus RNA/ATAC sequencing, and bulk RNA-seq, across fresh cells and organoids. Integration with public datasets produced the largest single-cell atlas of normal and high-risk FTs to date. This analysis defined high-specificity gene signatures for secretory and multiciliated lineages that outperform canonical lineage markers (e.g. PAX8, FOXJ1), identified lineage-defining transcription factors and regulatory networks, and showed concordant protein expression in the human FT epithelium. Notably, subcluster-level analysis revealed a rare hybrid epithelial-mesenchymal population transcriptionally and proteomically aligned with the mesenchymal-like subtype of HGSOC. Spatial immunoprofiling demonstrated that these cells express multiple defining markers and reside above the basement membrane, intercalated between epithelial cells and lack luminal contact, reminiscent of the histologically described peg cell population. Comparative analyses with fetal mesonephric tissues uncovered developmental parallels, and this population was stably maintained in 3D organoid cultures, providing a robust ex-vivo model to study early transformation. Together, our findings identify a rare, multipotent epithelial population with mesenchymal features as a candidate origin for mesenchymal-like HGSOC and establish the FT organoid biobank as a powerful platform for mechanistic and translational studies in ovarian carcinogenesis. Citation Format: Megan L. Ritting, Wenmei Yang, Syed Mohammed Musheer Aalam, Hui Zhao, Liang Feng, Jianning Song, Mihai G. Dumbrava, Wazim M. Ismail, Kenneth Schaufelberger, S. John Weroha, Scott H. Kaufmann, Alexandre Gaspar-Maia, Mark E. Sherman, Jamie N. Bakkum-Gamez, Nagarajan Kannan. A rare multipotent peg-like epithelial cell is a candidate cell-of-origin for high-grade serous ovarian 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 7636.

Objectives: For locally advanced rectal adenocarcinoma (R-ACA), a nonoperative management (NOM) approach has emerged as a guideline-supported treatment option. However, the variables associated with NOM receipt are unknown. Methods: Utilizing the National Cancer Database, we performed a retrospective cohort study of adults with stage 1 to 3 R-ACA managed with curative intent from 2004 to 2018. The primary outcome was the proportion of patients receiving NOM versus surgery. The secondary outcome was survival among NOM patients. Results: A total of 128,297 patients were included. In all, 115,888 (90.3%) received surgery and 12,409 (9.7%) received NOM. Receipt of NOM was associated with age above 70, Charlson-Deyo score of 0, race (Black, Asian or Pacific Islander, or other vs. White), insurance status, geographical region, treatment in a community facility, year of diagnosis (2012-2018 vs. 2004-2011), tumor grade 1 versus ≥ 2, clinical T-stage ≥ 2, and clinical N1 or N2 versus N0. In the NOM cohort, poorer overall survival was associated with age 70 and above, male sex, Charlson-Deyo score ≥ 1, insurance status, geographical region, rural urban density versus metro/urban, treatment in a community facility, year of diagnosis (2004-2011 vs. 2012-2018), clinical T4 versus T1, clinical N1 or N2 versus N0, grade 3 versus 1, treatment with a radiotherapy dose <45 Gy versus 45 to 54 Gy, and omission of chemotherapy. Conclusions: Several demographic factors and social determinants of health were associated with receipt of NOM and overall survival. With the increasing utilization of NOM, it will be important to understand the drivers of treatment decisions and influences on access to the desired treatment approach.

e16157 Background: The optimal treatment for resectable gastric/GEJ AC is unclear due to limited direct comparisons among chemotherapy and chemoradiation regimens. Addressing this gap is critical to improve patient outcomes. We performed this network meta-analysis (NMA) to determine the relative efficacy of multimodality regimens for resectable gastric/GEJ AC. Methods: MEDLINE, EMBASE, Scopus, and CENTRAL were searched from inception till September 20, 2024, to identify phase III trials evaluating perioperative/neoadjuvant systemic therapy ± radiation in resectable gastric/GEJ AC. Primary outcomes were disease-free survival (DFS) and overall survival (OS). A frequentist NMA was conducted to compare hazard ratios (HR) and 95% CI for each outcome. Relative treatment rankings were assessed using P-scores. Results: Fifteen trials (8,072 patients) were analyzed. pFLOT (perioperative fluorouracil, leucovorin, oxaliplatin, and docetaxel) ranked highest for DFS in the overall population (P score 91%) (Table), significantly outperforming surgery alone (HR 0.48, 95% CI 0.38-0.60) and nCROSS (neoadjuvant paclitaxel, carboplatin and radiotherapy) (0.67, 0.56-0.81). For OS, nPLF+nCRT(EP) (neoadjuvant cisplatin, leucovorin and fluorouracil for induction, followed by etoposide, cisplatin, and radiotherapy) (P score 90%) and pFLOT (P score 87%) were the top regimens, with pFLOT significantly outperforming surgery alone (0.57, 0.45-0.72), and nCROSS (0.73, 0.60-0.89). Adding neoadjuvant chemoradiation to pFLOT provided no additional OS (1.14, 0.76-1.72) or DFS (1.22, 0.83-1.82) benefit. Similarly, adding pembrolizumab to perioperative chemotherapy (CF/CX) (cisplatin and fluorouracil/capecitabine) was not superior to pFLOT in terms of DFS (1.10, 0.71-1.69) or OS (1.09, 0.69-1.72). Conclusions: pFLOT demonstrated superior efficacy in resectable gastric/GEJ AC, surpassing surgery alone, nCROSS, and other perioperative regimens. The additive role of immunotherapy to pFLOT requires further investigation to refine patient selection and optimize outcomes. Regimen Overall Population GEJ cohort OS DFS OS DFS nPLF+nCRT(EP) 1 (90) 2 (84) 1 (85) NA pFLOT 2 (87) 1 (91) 2 (79) 2 (88) pPembrolizumab+CF/CX 3 (75) 3 (81) 5 (41) - nECX 4 (61) 5 (55) - - pCF 5 (59) 8 (51) 3 (72) - pECF/ECX 6 (47) 6 (55) 7 (40) 3 (57) nECX+aCRT(CX) 7 (45) 7 (52) 9 (31) - nCF 8 (42) 10 (28) 6 (40) - nCROSS 9 (41) 9 (35) 8 (34) 4 (43) pECF/ECX/FLOT+nCRT(F/X) 10 (38) 4 (57) 4 (72) 1 (90) nCRT(CF) 11 (9) 11 (6) - 5 (14) Surgery 12 (7) 12 (5) 10 (5) 6 (9) Data reported as rank (P-score). Abbreviations: n: neoadjuvant; p: perioperative; ECX: epirubicin + cisplatin + capecitabine; CF: cisplatin + fluorouracil; ECF: epirubicin + cisplatin + fluorouracil; aCRT(CX): adjuvant radiotherapy + cisplatin + capecitabine; CRT(F/X): fluorouracil/capecitabine + radiotherapy; CRT(CF): cisplatin + fluorouracil + radiotherapy.

Abstract Background: Given the dramatic rise in incidence of colorectal cancer in young adults, there remain limited treatment options effective in metastatic disease. Although T cell-based therapies have been successful in treating highly antigenic cancers, like melanoma and lung, they have not yet been shown to induce consistent and durable tumor regression in common epithelial malignancies, including metastatic colorectal cancer (mCRC). CISH (Cytokine inducible SH2 containing protein) is a novel intracellular checkpoint target demonstrating PD-L1 ligand independent mechanisms of enhanced anti-cancer activity. Given that CISH is not currently tractable via antibody or small molecule drug modalities, we employed CRISPR for precise inhibition of CISH in tumor infiltrating lymphocytes (TILs). Here, we provide the first clinical report of safety and anti-tumor activity of CISH edited TILs in 12 patients with metastatic gastrointestinal cancers (NCT04426669), including a clinical complete response (CR) in a young-adult patient with immunotherapy-refractory mCRC. Methods: Tumors were surgically resected for TIL harvest, followed by a rapid expansion protocol and CRISPR/Cas9 knockout (KO) CISH. CISH KO, neoantigen-reactive TILs were expanded, then infused following non-myeloablative lymphocyte depleting (LD) chemotherapy (cyclophosphamide & fludarabine) followed by high-dose IL-2. To establish mechanistic attribution of the CR, we used iR-RepSeq+ for serial analysis of the TCR immune repertoire. Results: Our CRISPR engineering led to KO of CISH in T cells with high-efficiency (&gt;90%) without detectable off-target editing. We safely dosed patients at all five dose levels (range: 1.91e8 to 9.93e10 cells). No dose-limiting toxicities attributable to the CISH-KO TIL product were observed. Adverse events were consistent with established risks of LD chemotherapy, IL-2, or disease progression. A durable ongoing complete response (&gt;21 months) was achieved in a patient with microsatellite instability-high (MSI-H) mCRC refractory to anti-PD1/CTLA-4 combination therapy. Conclusions: We provide the first clinical report of CISH checkpoint targeting via genetically modified T cell therapy, with complete response in a patient with mCRC. Persistence and expansion of unique TCR clonotypes detected in neoantigen responsive TIL was temporally consistent with spikes in CISH edited alleles detected by NGS assay; in the patient with CR, four of the clonotypes exhibiting prolonged persistence greater than one-year post-infusion exhibited significantly reduced or undetectable expression of CISH compared to the total infused TIL population. Given these findings, further investigation of CISH checkpoint inhibition, via gene and cell therapy, and next-generation small molecule drugging modalities, is underway. Citation Format: Emil Lou, Modassir S. Choudhry, Timothy K. Starr, Timothy Folsom, Jason Bell, Blaine Rathmann, Anthony P. DeFeo, Ji Hyun Kim, Nicholas Slipek, Zhaohui Jin, Darin Sumstad, Christopher A. Klebanoff, Katherine Ladner, Akshat Sarkari, R Scott McIvor, Thomas A. Murray, Jeffrey Miller, Madhuri Rao, Eric Jensen, Jacob Ankeny, Mahmoud A. Khalifa, Anil Chauhan, Benjamin Spilseth, Ajay Dixit, Paolo P. Provenzano, Wenjing Pan, Daniel Weber, Miranda Byrne-Steele, Tom Henley, David H. McKenna, Matthew J. Johnson, Beau R. Webber, Branden S. Moriarity. First-in-human trial in patients with metastatic colorectal cancer using CRISPR-engineered tumor infiltrating lymphocytes in which the intracellular immune checkpoint CISH is inhibited [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_2):Abstract nr CT269.

84 Background: Local therapies potentially offer a curative approach for patients with oligometastatic colorectal cancer (CRC). The effectiveness of systemic chemotherapy following definitive local treatment in this setting is not well-defined. Tumor-informed circulating tumor DNA (ctDNA) might guide management strategies after curative-intent local treatment. Methods: This is a single institution retrospective study of patients with CRC who underwent curative-intent local therapy to an isolated site of metastatic disease and had post-intervention tumor-informed ctDNA (Signatera) testing. The study was approved by the institutional review board. Clinical characteristics, including ctDNA results, were collected and evaluated. Kaplan-Meier method and log-rank test were used to calculate and compare disease-free survival (DFS). Factors associated with DFS were analyzed using multivariate Cox proportional hazards model. Results: 45 patients were included with median age of 59 years, 62% being male, 91% white, and 53% with stage IV disease at diagnosis. 37% of the patients had RAS mutations, no patient had BRAF mutation, and 2.2% patient had mismatch repair deficient disease. Isolated liver metastases were present in 80% of patients, lung metastases in 11% and other sites in 9%. 44 patients received chemotherapy prior to definitive treatment, with a median treatment duration of 16 weeks. ctDNA tests were done prior to local therapy in 23 patients, with 14 cases (61%) testing positive. Definitive treatment included resection (58%), ablation (13%), radiotherapy (4%), and multimodality (25%). Post-definitive treatment chemotherapy was administered to 24 (53%) patients. ctDNA positivity following definitive therapy was observed in 10 patients (22%), which was associated with a poorer prognosis, with a median DFS of 5.3 months compared to 21.3 months for the ctDNA-negative group (p<0.001). These findings were confirmed on multivariate analysis. In patients who had negative ctDNA after definitive local treatment, median DFS was 14.9 months for those who received post-intervention chemotherapy versus 21.3 months for those without post-intervention chemotherapy (p=0.835). Conclusions: Patients with negative ctDNA results following definitive local therapy for isolated metastatic CRC have better prognosis. Post-intervention chemotherapy in this group of patients was not associated with improved DFS. ctDNA guided omission of post-intervention chemotherapy following curative-intent local treatment of oligometastatic CRC warrants further study. [Table: see text]

Abstract Background No human rabies post-exposure prophylaxis (PEP) failure has been documented in the United States using modern cell culture–based vaccines. In January 2021, an 84-year-old male died from rabies 6 months after being bitten by a rabid bat despite receiving timely rabies PEP. We investigated the cause of breakthrough infection. Methods We reviewed medical records, laboratory results, and autopsy findings and performed whole-genome sequencing (WGS) to compare patient and bat virus sequences. Storage, administration, and integrity of PEP biologics administered to the patient were assessed; samples from leftover rabies immunoglobulin were evaluated for potency. We conducted risk assessments for persons potentially exposed to the bat and for close patient contacts. Results Rabies virus antibodies present in serum and cerebrospinal fluid were nonneutralizing. Antemortem blood testing revealed that the patient had unrecognized monoclonal gammopathy of unknown significance. Autopsy findings showed rabies meningoencephalitis and metastatic prostatic adenocarcinoma. Rabies virus sequences from the patient and the offending bat were identical by WGS. No deviations were identified in potency, quality control, administration, or storage of administered PEP. Of 332 persons assessed for potential rabies exposure to the case patient, 3 (0.9%) warranted PEP. Conclusions This is the first reported failure of rabies PEP in the Western Hemisphere using a cell culture–based vaccine. Host-mediated primary vaccine failure attributed to previously unrecognized impaired immunity is the most likely explanation for this breakthrough infection. Clinicians should consider measuring rabies neutralizing antibody titers after completion of PEP if there is any suspicion for immunocompromise.

AbstractModern fluoroscopes used for image guidance have become quite complex. Adding to this complexity are the many regulatory and accreditation requirements that must be fulfilled during acceptance testing of a new unit. Further, some of these acceptance tests have pass/fail criteria, whereas others do not, making acceptance testing a subjective and time‐consuming task. The AAPM Task Group 272 Report spells out the details of tests that are required and gives visibility to some of the tests that while not yet required are recommended as good practice. The organization of the report begins with the most complicated fluoroscopes used in interventional radiology or cardiology and continues with general fluoroscopy and mobile C‐arms. Finally, the appendices of the report provide useful information, an example report form and topics that needed their own section due to the level of detail.

Abstract A data-independent acquisition (DIA) approach is being increasingly adopted as a promising strategy for identification and quantitation of proteomes. As most DIA data sets are acquired with wide isolation windows, highly complex MS/MS spectra are generated, which negatively impacts obtaining peptide information through classical protein database searches. Therefore, the analysis of DIA data mainly relies on the evidence of the existence of peptides from prebuilt spectral libraries. Consequently, one major weakness of this method is that it does not account for peptides that are not included in the spectral library, precluding the use of DIA for discovery studies. Here, we present a strategy termed Precursor ion And Small Slice-DIA (PASS-DIA) in which MS/MS spectra are acquired with small isolation windows (slices) and MS/MS spectra are interpreted with accurately determined precursor ion masses. This method enables the direct application of conventional spectrum-centric analysis pipelines for peptide identification and precursor ion-based quantitation. The performance of PASS-DIA was observed to be superior to both data-dependent acquisition (DDA) and conventional DIA experiments with 69 and 48% additional protein identifications, respectively. Application of PASS-DIA for the analysis of post-translationally modified peptides again highlighted its superior performance in characterizing phosphopeptides (77% more), N-terminal acetylated peptides (56% more), and N-glycopeptides (83% more) as compared to DDA alone. Finally, the use of PASS-DIA to characterize a rare proteome of human fallopian tube organoids enabled 34% additional protein identifications than DDA alone and revealed biologically relevant pathways including low abundance proteins. Overall, PASS-DIA is a novel DIA approach for use as a discovery tool that outperforms both conventional DDA and DIA experiments to provide additional protein information. We believe that the PASS-DIA method is an important strategy for discovery-type studies when deeper proteome characterization is required.

Abstract An international consensus on antineutrophil cytoplasm antibodies (ANCA) testing in eosinophilic granulomatosis with polyangiitis (EGPA) is presented. ANCA, specific for myeloperoxidase (MPO), can be detected in 30–35% of patients with EGPA. MPO-ANCA should be tested with antigen-specific immunoassays in any patient with eosinophilic asthma and clinical features suggesting EGPA, including constitutional symptoms; purpura; polyneuropathy; unexplained heart, gastrointestinal, or kidney disease; and/or pulmonary infiltrates or hemorrhage. A positive MPO-ANCA result contributes to the diagnostic workup for EGPA. Patients with MPO-ANCA–associated EGPA have vasculitis features, such as glomerulonephritis, neuropathy, and skin manifestations, more frequently than patients with ANCA-negative EGPA. However, the presence of MPO-ANCA is neither sensitive nor specific enough to identify whether a patient should be subclassified as having “vasculitic” or “eosinophilic” EGPA. At present, ANCA status cannot guide treatment decisions, that is, whether cyclophosphamide, rituximab, or mepolizumab should be added to conventional glucocorticoid treatment. In EGPA, monitoring of ANCA is only useful when MPO-ANCA was tested positive at disease onset.