ABSTRACT Background Transvenous lead extraction (TLE) is a commonly performed and generally safe procedure, though procedural complexity and risk can vary based on clinical and procedural factors. Objective This study aims to identify clinical and procedural factors associated with histologic evidence of subclinical vascular injury, defined by elastin positivity on extracted leads and its clinical significance. Methods Patients undergoing TLE with a lead dwell time of ≥ 1 year were included. Extracted leads with tissue were analyzed histologically using Verhoeff–Van Gieson staining to assess the presence of elastin. Demographic data, procedural and lead characteristics, and indication for extraction were obtained. Established extraction risk scores were calculated to determine efficacy in predicting subclinical vascular injury. Results The cohort included 49 patients with 92 leads extracted. A total of 25 patients (51%) had elastin‐positive leads. Complete procedural success occurred in 95.9% of cases. The multivariate regression model did not identify any independent predictors of elastin presence, including age (OR = 1.00; 95% CI 0.95–1.05; p = 0.89), female gender (OR = 3.04; 95% CI 0.67–13.65; p = 0.14), lead dwell time (OR = 1.13; 95% CI 0.98–1.29; p = 0.07). Additionally, no scoring system, such as the CCF, EROS, MB, SAFeTY, and LECOM, predicted the presence of elastin. Conclusion Subclinical venous injury was common following TLE, yet did not predict adverse clinical outcomes, reinforcing that TLE performed in experienced centers carries a favorable safety profile. Future studies in larger cohorts are needed to further characterize the clinical utility of subclinical vascular injury.
Pathology Foundation Models: Evolution, Current Landscape, Challenges and Opportunities from a Technical and Clinical Perspective
Foundation models are reshaping computational pathology by enabling scalable task-agnostic representations of histopathological whole-slide images (WSIs). Unlike earlier task-specific deep learning systems, pathology foundation models (PFMs) leverage massive whole-slide image repositories and self-supervised Vision Transformer architectures to achieve broad generalization and few-shot adaptability. Their evolution reflects a shift from weakly supervised approaches such as Clustering-Constrained Attention Multiple Instance Learning (CLAM) and hierarchical architectures such as Hierarchical Image Pyramid Transformer (HIPT) to large-scale efforts including foundation models, UNI, Virchow, Phikon, CONtrastive learning from Captions for Histopathology (CONCH), GigaPath, H-Optimus, Transformer-Based Pathology Image and Text Alignment Network (TITAN), and the Mayo Clinic Atlas. These models demonstrate impressive performance across diagnostic and prognostic benchmarks while also opening pathways for multimodal integration with genomics and clinical data. Yet significant barriers remain including inconsistent generalization across institutions, interpretability lagging behind clinical needs, and slow integration into routine laboratory workflows. Certain domains of anatomic pathology such as cytopathology, transplant pathology, frozen sections, and rare tumor subtypes remain particularly resistant to current models. Here, we review the development of PFMs, critically evaluate their strengths and limitations, and outline priorities for their safe and effective clinical translation. We argue that the next phase of PFM development will depend on rigorous benchmarking, pathologist-in-the-loop deployment, and multimodal fusion ensuring these models evolve from research tools into clinically robust systems.
Case Report: durable response to pulsed electric field ablation in combination with immune checkpoint inhibitors in HER2-low breast cancer through activation of interferon signaling
Pulsed Electric Field (PEF) ablation is a non-thermal cancer treatment that disrupts tumor cell membranes while preserving the immune microenvironment and promoting immunogenic cell death. We present a case of a patient with metastatic hormone receptor-positive, HER2-low breast cancer who achieved a durable clinical response after PEF in combination with an immune checkpoint inhibitor (pembrolizumab). The patient remained off systemic therapy for 14 months without disease progression. Single-cell spatial molecular imaging (SMI) and gene set enrichment analysis (GSEA) were performed to evaluate immune microenvironment changes pre- and post-PEF treatment. Spatial transcriptomics of the tumor cell compartment revealed a post-PEF enrichment of immune-related pathways, including interferon alpha/beta and gamma signaling and MHC class I antigen processing and presentation, alongside increased infiltration of immune cells: CD8+ T cells, plasmablasts, and monocytes within the tumor neighborhood. This hypothesis-generating case suggests PEF’s potential to reshape the tumor-immune microenvironment when combined with immune checkpoint blockade, warranting further studies on its role in combination immunotherapy strategies.
Abstract 6715: 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 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.
Anal Squamous Cell Carcinoma with Bilateral Renal Metastases: A Rare Presentation with Literature Review
Anal squamous cell carcinoma (ASCC) is a rare malignancy of the lower gastrointestinal tract, with distant metastases typically involving the liver and lungs. Metastasis to the kidneys is uncommon, and only one prior case has been reported in the literature. Herein, we report a rare presentation of a patient with biopsy-confirmed metastatic ASCC presenting as bilateral renal lesions. We then provide a review of the literature for rare metastatic presentations of ASCC, highlighting all the cases described in the literature. Clinicians should maintain a high index of suspicion for unusual metastatic sites, perform targeted imaging and biopsy when indicated, and consider systemic therapies to optimize outcomes in rare metastatic presentations.
Concordance of Oncotype DX Breast Recurrence Score Assay Results Between Paired Core Needle Biopsy and Surgical Excision Specimens in Hormone Receptor Positive, Human Epidermal Growth Factor Receptor 2 Negative, Early-Stage Breast Cancer
PURPOSE The feasibility of Oncotype DX Breast Recurrence Score testing on diagnostic core needle biopsy (CNB) samples has been demonstrated through analysis of a large central laboratory experience. However, concordance with paired samples from the same primary breast tumor has not been comprehensively evaluated. The primary objective of this study was to determine the degree of concordance of Recurrence Score (RS) results between paired CNB and surgical excision (SE) specimens from the same untreated primary breast tumor of patients with early-stage, hormone receptor–positive, human epidermal growth factor receptor 2–negative invasive breast cancer. MATERIALS AND METHODS Patients with a clinical RS result on either a CNB or SE specimen were included. Lin concordance correlation coefficient (CCC) with 95% CIs was estimated to assess agreement of continuous RS results between paired samples. Cohen Kappa with 95% CIs was used to evaluate categorical RS result concordance. RESULTS A total of 134 patients were identified with paired CNB and SE specimens. The median age was 62 years (range, 33-99; 23 patients [17%] were age ≤50 years v 111 [83%] age >50 years). The mean RS results were 15.6 (range, 0-56) for CNB and 16.6 (range, 0-59) for SE ( P = .003), with no statistically significant differences in RS categories. Agreement between continuous RS results from paired samples was strong, with a Lin CCC of 0.86 (95% CI, 0.80 to 0.90). The overall percent agreement in RS categories was 91.8% (95% CI, 87.1 to 96.4). Categorical agreement was further supported by a Cohen Kappa statistic of 0.64 (95% CI, 0.44 to 0.83), indicating substantial agreement between CNB and SE specimens. CONCLUSION The results of this study demonstrate high concordance of RS results between paired samples, which supports the use of CNB for Oncotype DX testing.
516 Plasmablastic lymphoma transformation in association with chimeric antigen receptor T cells therapy for refractory diffuse large B-cell lymphoma
Abstract Introduction/Objective Plasmablastic lymphoma (PBL) is a rare type of B-cell lymphoma with poor prognosis. They can arise de novo in immune deficiency/dysregulation, associated with transplant or transformation of low grade lymphoma. PBL has been reported with anti-CD19 chimeric antigen receptor (CAR) T-cell therapy. Methods/Case Report 69-year-old male with CLL/SLL, treated with multiple chemotherapy regimens and was in remission. He developed generalized weaknesses. Radiology showed lymphadenopathy. Pathology was positive for DLBCL without MYC and BCL2 rearrangement. Flow cytometry revealed 1% CD5 and CD23 positive. TP53 is negative and mutated IGHV. The PD-1 was negative, favored de novo DLBCL. PET-CT and biopsy confirmed residual disease. For refractory DLBCL, CAR-T cell therapy was initiated. Patient developed PBL diffusely positive for CD138, MUM1, c-MYC and kappa; negative for CD19, CD20, PAX5, CD10, BCL6 and CD79a. MIB-1 was 90%. EBV and HHV8 were negative. BCMA was >95 %, Teclistamab was initiated. The renal function deteriorated and proceeded with palliative care. Results NA Conclusion The nature of Richter transformation or de novo DLBCL into PBL in the setting of immunomodulation with CAR-T is rare occurrence. Molecular and clonality studies are needed to evaluate the pathways of losing B-cell markers to evade lineage specific therapy.
457 Invasive Breast Carcinomas Arising in Association with Microglandular Adenosis: A Case Series Analysis
Abstract Introduction/Objective Microglandular adenosis (MGA) of the breast is an uncommon lesion characterized by a benign course. However atypical MGA (AMGA) and MGA-associated carcinoma have been described, suggesting that MGA may represent a non-obligate precursor of carcinoma. We report five cases of MGA-associated breast carcinoma and describe the key pathological features of this entity. Methods/Case Report Five cases of MGA-associated breast carcinoma were identified. Clinical data, histologic and immunohistochemical characteristics were reviewed and analyzed. Results All cases involved women with ages ranging 48 to 75 with a median of 70. Four of five cases demonstrated invasive carcinoma, while one case showed ductal carcinoma in-situ (DCIS). Invasive carcinomas encompassed various histologic types: metaplastic carcinoma with chondromyxoid matrix production (2 cases), invasive carcinoma with secretory features (1 case), and invasive carcinoma of no special type (ductal) (1 case). A morphologic transition from MGA to AMGA to carcinoma was observed in all cases. S100 was consistently positive in all cases. Myoepithelial markers demonstrated the absence of myoepithelial cells in the invasive carcinoma as well as MGA / AMGA component. Conclusion This series highlights the histologic spectrum and key diagnostic features of MGA-associated carcinoma. Awareness of this entity is crucial for appropriate diagnosis and clinical management.
A Phase II Trial to Evaluate the Safety and Immunogenicity of Two Doses of a Folate Receptor Alpha Vaccine in Patients with Triple-Negative Breast Cancer
Abstract Purpose: CD4 T-cell immunity is associated with improved survival in patients with breast cancer. We previously reported a phase I trial evaluating a folate receptor alpha (FRα) vaccine administered with cyclophosphamide (CP), demonstrating excellent safety and immunogenicity. To simplify the vaccine strategy for ease of use, we report here the results of a randomized phase II trial evaluating a lower vaccine dose alongside the original dose, administered with or without CP pretreatment. Patients and Methods: Patients with triple-negative breast cancer who completed all systemic and local therapies were assigned to receive either low-dose (825 μg) or high-dose (2.5 mg) vaccine peptides plus GM-CSF in six 4-week cycles, with or without CP prior to vaccination. Safety was monitored, and immunogenicity was evaluated before and after vaccination. Results: A total of 80 patients were dosed with vaccine, and 58 patients were evaluable for immunogenicity. Vaccination was well tolerated and elicited immunity in 83% of patients. Levels of FRα-specific T cells were high, persistent, and comparable with T-cell levels against tetanus toxoid. No differences in immunity were observed between the two doses. CP pretreatment also did not affect the immune responses. Recurrences occurred in eight evaluable patients and were unrelated to the treatment arm. No patients died during the study because of their disease. Conclusions: The reduced-dose FRα vaccine is as effective as the original dose and does not require CP to generate maximal immunity. These findings may inform the design of trials testing efficacy in triple-negative breast cancer or other cancers.
Tissue Acquisition Techniques Take Center Stage: Discussion Synopsis of Papanicolaou Society of Cytology Companion Session at International Academy of Cytology Congress, Florence, Italy