Citations

Abstract Recent single-cell transcriptomic studies of follicular lymphoma (FL) have revealed heterogeneity among malignant B (MB) cells and selected components of the tumor microenvironment (TME), but have been constrained by relatively small sample sizes and a lack of spatial context. We performed comprehensive cellular profiling and spatial dissection of over five million cells by integrating single-nucleus RNA sequencing (snRNA-seq) from 182 samples (FL, n = 167; control, n = 15) with single-cell spatial transcriptomics (ST) from 386 samples (FL, n = 365; control, n = 21). After stringent quality control, 1,289,073 and 3,968,427 cells from snRNA-seq and ST data, respectively, were analyzed. Unsupervised clustering of snRNA-seq data identified 58 TME cell subtypes. To extend this classification to the ST dataset, we integrated snRNA-seq and ST data by co-embedding them into a shared principal component space, enabling robust batch correction and cell-type label transfer across modalities. Using this supervised annotation framework, ST data recapitulated 54 TME cell subtypes. MB, proliferating MB (MBprolif), and healthy B (HB) cells were classified using sample-level unsupervised clustering in ST. Macrophages exhibited previously uncharacterized heterogeneity in transcriptomic profiles and spatial distribution. We identified CXCL13-expressing macrophage subtypes with high intra- and peri-follicular abundance, termed follicular macrophages (FMs). Non-negative matrix factorization of intrafollicular cell fractions identified five TME archetypes: FM, follicular stroma, two follicular T, and HB archetypes. The FM archetype was enriched for intrafollicular macrophages, including FMs, and showed a significantly higher proportion of grade 3A/3B cases (53.4%) compared to other archetypes (≤16.5%). It was also associated with a higher frequency of high tumor burden requiring treatment initiation rather than a watch-and-wait (WW) approach. Among patients managed by WW, those with the FM archetype showed significantly shorter event-free survival (EFS) compared to those with non-FM archetypes, whereas this association was not observed among treated patients. The percentage of intrafollicular macrophages (IFMP) showed excellent predictive performance for the FM archetype (area under the curve: 0.90). IFMP calculated in a published multiplex spatial protein imaging dataset from an independent cohort of 242 FL patients validated the associations between high IFMP and both pathology grade 3A/3B and shorter EFS in WW patients. Consistently, spatial neighborhood and cell–cell communication analyses revealed co-localization of FMs and MBprolif cells, forming a distinct niche with activated signaling mediated by FM-derived CXCL13, APRIL, and BAFF. Our integrative multi-modal analysis defines previously unrecognized cellular heterogeneity and spatial architecture in FL and highlights macrophage-enriched follicular ecosystems associated with aggressive clinicopathological features, providing a framework for improved biological understanding and patient management. Citation Format: Yoshiaki Abe, Bijal Thakkar, Atish Kizhakeyil, Ashley Wilson, Andrew L. Feldman, Jared Henderson, Amy Ayers, Sara Borgschatz, R. Andrew Harkins, Priya Lakra, Daisuke Kaji, Jonathon B. Cohen, David Russler-Germain, Eric Mou, Francisco Vega, Jennifer Chapman, Giorgio Inghirami, Carla Casulo, Izidore S. Lossos, Jean L. Koff, Chijioke Nze, Peter Martin, Sergei Syrbu, Kiran Vij, David L. Jaye, James R. Cerhan, Christopher R. Flowers, Anne J. Novak, Richard Burack, Dai Chihara, Mamiko Sakata-Yanagimoto, Joshua Tobin, Xubin Li, Michael R. Green. Spatially resolved microenvironment profiling reveals distinct follicular lymphoma archetypes [abstract]. In: Proceedings of the Fifth AACR International Meeting on Advances in Malignant Lymphoma: From Discovery to Clinical Impact; 2026 Jun 24-27; Philadelphia, PA. Philadelphia (PA): AACR; Blood Cancer Discov 2026;7(3_Suppl):Abstract nr A049.

Abstract Background Approximately 12,000 adolescents and young adults (ages 15-39, AYAs) are diagnosed with a primary central nervous system (CNS) tumor each year. DNA methylation profiling has transformed CNS tumor classification by refining diagnostic accuracy and identifying biologically distinct subtypes, but its application has not been systematically evaluated in the AYA population. In this study, we examined the spectrum of CNS tumor types across age groups, with a focus on the AYA population. Methods We assembled a large dataset of CNS tumor samples with age annotations and methylation profiles matching with high confidence to a CNS tumor type using the NCI/Bethesda classifier. Prevalence of tumor type, methylation class and DNA copy number aberrations were compared across age strata (pediatric, AYA and adult). Results The cohort of 21,099 CNS tumors included 5139 tumors from AYAs (24%), which showed a mixed pattern, with tumors typical of childhood (e.g. medulloblastoma) as well as those common in older adults (e.g. glioblastoma). Several tumor types were specifically enriched in the AYA, including IDH-mutant astrocytoma, pleomorphic xanthoastrocytoma, posterior fossa group B ependymoma, and diffuse hemispheric glioma, H3 G34-mutant, among others. Distinct methylation subclasses of multiple tumor types were observed in the AYA, and patterns of genomic aberrations showed age-specific distributions. Conclusion Large-scale methylation profiling revealed unique classification patterns of CNS tumors in AYAs, with specific tumor types, subclasses, and genomic alterations enriched in this population. These data may serve as a valuable reference resource for better understanding the spectrum of CNS tumors affecting AYA patients.

Background: There is growing evidence that social determinants of health (SDOH) are associated with disparities in access to care and hand and upper extremity health. Quality measures represent an opportunity to evaluate disparities in access and outcomes that can inform improvement interventions. We performed a systematic review of evidence regarding health disparities within hand surgery and aimed to develop suitable quality measures that are clinically important, feasible, usable, and scientifically acceptable. Methods: We performed a systematic review including common hand surgery terms to identify health disparities in hand surgery related to SDOH. Candidate quality measures were constructed based upon evidence from the systematic review. A consortium of 11 US-based hand and upper extremity surgeons completed a modified RAND/UCLA Delphi Appropriateness process to evaluate the importance, feasibility, usability, and scientific acceptability of the candidate quality measures. Panelists rated each measure on a scale of 1 ( definitely not important/feasible/usable/scientifically acceptable ) to 9 ( definitely important/feasible/usable/scientifically acceptable ) in 2 voting rounds separated by a face-to-face discussion. Agreement among panelists and validity were assessed using predetermined criteria. Results: Fourteen candidate quality measures addressing health disparities were identified based on evidence from the systematic review, including time to surgery and emergency department use after hand surgery based on insurance type, clinical outcomes based on social deprivation, among others. All 14 measures were accepted. Conclusions: Fourteen candidate quality measures were identified and accepted based upon consensus to address health disparities in hand surgery, although future investigation will be needed to evaluate their effectiveness.

Vanishing bile duct syndrome is a rare complication of classical Hodgkin’s lymphoma (cHL) which may present with significant cholestasis and hepatic dysfunction. Management is primarily focused on chemotherapy and symptomatic management of cholestatic liver failure. We describe a case of a man in his 60s with relapsed cHL with significant cholestatic liver injury who was treated with brentuximab vedotin complicated by renal failure. The complex decision-making surrounding chemotherapeutic choice with the presence of multiorgan dysfunction is discussed with a review of literature describing regimens in similar clinical circumstances.

Abstract Myelodysplastic syndromes (MDS) are clinically and biologically diverse disorders, emphasizing the need for personalized treatment approaches. The International Working Group for Prognostication of MDS (IWG_PM) recently introduced a molecular classification, referred to as the MDS taxonomy, that categorizes patients into 16 subgroups based on 21 gene mutations, 6 cytogenetic abnormalities, and loss of heterozygosity (LOH) at TP53 and TET2 loci. This study sought to validate and enhance the clinical relevance of the MDS taxonomy by analyzing a large retrospective cohort ( n = 5136) and transcriptomic data from a prospective cohort ( n = 477). The taxonomy successfully identified subgroups with distinct clinical characteristics and disease progression patterns. However, incorporating gene interactions from taxonomy subgroups did not improve the prognostic performance of the Molecular International Prognostic Scoring System (IPSS‐M). We further assessed whether the taxonomy could guide management in patients receiving disease‐modifying therapies. Except for the “ TP53 ‐complex” subgroup, taxonomy classifications were not predictive of hypomethylating agent response or transplant outcomes. Nonetheless, they correlated with overall survival, suggesting that while both IPSS‐M and the taxonomy capture disease biology, other non‐genetic factors may influence treatment response. RNA sequencing confirmed the biological distinctiveness of the taxonomy groups. Transcriptomic profiling of CD34+ bone marrow cells revealed unique, homogeneous gene expression patterns, particularly within the AML‐like, bi TET2 , SF3B1 , and TP53 ‐complex subgroups. Further integration of multi‐omics data may refine MDS classification, improving clinical decision‐making and guiding the development of targeted therapies.

Multiple sclerosis is an immune-driven neurological disease that affects myelinated axons in the central nervous system. However, the trigger of the (dysregulated) immune reactions is not known. According to Wilkin’s primary lesion theory, myelin-reactive T cells present in the immune repertoire hyper-react to myelin antigens that are released from idiopathic lesions within the central nervous system. However, neither the cause of the primary lesion nor the cause of the immune hyper-reactivity is known. We investigated whether these unknown activation signals may be relayed by common herpesviruses. In this concept paper, we propose the novel paradigm that the trigger of autoimmunity in MS comprises a conspiracy of three common herpesviruses: human herpesvirus-6A as a potential trigger of primary lesions due to its proven capacity to cause oligodendrogliopathy, cytomegalovirus as a trigger for the formation of effector memory cytotoxic T cells with proven capacity to induce multiple sclerosis pathology in a non-human primate MS model and Epstein-Barr Virus due to its capacity to render B cells capable to effectively present a critical myelin antigen to these effector memory cytotoxic T cells.

Background: Hepatic stellate cells (HSCs) play a pivotal role in driving fibrosis during chronic liver injury. HSCs produce vast amounts of fibrotic proteins, causing endoplasmic reticulum (ER) stress and initiating the unfolded protein response (UPR). While the UPR is important for fibrogenesis, how signaling through UPR transducer Protein Kinase R-like ER Kinase (PERK) and its effectors impact HSC activation and fibrogenesis is unclear. Here, we sought to uncover the role of PERK and its effector GADD45A in liver fibrosis. Methods: PERK–GADD45A signaling was assessed in primary and immortalized HSCs treated with TGFβ, and mouse models of fibrosis. Genetic and pharmacological disruption of PERK or GADD45A was used to assess the role of PERK or GADD45A in HSC activation, proliferation, and fibrogenesis. HSC-specific Gadd45a -null mice were utilized to investigate the role of GADD45A on CCl 4 -induced fibrosis. Results: We found that TGFβ-induction of collagen I drives activation of PERK signaling in HSCs. Furthermore, loss or inhibition of PERK limits long-term HSC activation as illustrated by reduced levels of collagen I and fibronectin, impaired collagen I deposition, and reduced cell proliferation in vitro. Next, we show that PERK signaling induces expression of GADD45A during HSC activation, and loss of GADD45A disrupts HSC activation and expression of proliferation and cell-cycle-associated genes in immortalized and primary HSCs. Finally, HSC-specific GADD4Aa loss limits CCl 4 -driven fibrogenesis in vivo. Conclusion: PERK signaling is critical for HSC activation, and loss of the PERK downstream effector GADD45A limits fibrosis progression. Disruption of HSC activation and proliferation, coupled with dysregulation of cell-cycle-associated genes upon PERK or GADD45A loss, suggests that PERK–GADD45A signaling impacts multiple facets of HSC pathophysiology.

Background: Despite recent advances in cleft care, Vietnam continues to have extensive involvement from international nongovernmental organizations (NGOs), creating a fragmented system with limited coordination. This project seeks to establish a baseline understanding of Vietnam’s cleft care landscape, including major international NGOs and their collaborations with local partners, costs and insurance coverage, and patterns applicable to other low- and middle-income countries with NGO-supported cleft care. Methods: We conducted a mixed-methods study using literature review and semi-structured interviews with surgeons, hospital administrators, and NGO representatives (n = 7). Sources included PubMed, targeted Google searches, and government regulations on NGO involvement, cleft care costs, and insurance policies. Results: Vietnam partners with 17 international NGOs that operate through 3 distinct but complementary models: vertical, horizontal, and diagonal models. These collaborations offer financial support, infrastructure, technology investment, and research development, leading to higher surgical volume, more timely access to care, and implementation of standardized multidisciplinary cleft services in Vietnam. National insurance provides broad coverage but requires a complex referral process with limited benefits for secondary cleft services. Limited awareness of insurance benefits and mistrust of local care further discourage the use of national health insurance. Conclusions: Improving access to comprehensive cleft services in Vietnam requires streamlining insurance referral pathways and decentralizing advanced cleft services to regional centers to ensure continuity of care. Aligning NGO activities with national policies is essential to building a coordinated and sustainable cleft care system in Vietnam and in other low- and middle-income countries with strong insurance frameworks and significant NGO involvement.