Citations

The chemotherapeutic 5‐fluorouracil (5‐FU) is commonly used to treat solid tumors, especially colorectal cancer. Deleterious variants in DPYD, which encodes dihydropyrimidine dehydrogenase (DPD), are strongly associated with severe and potentially lethal 5‐FU toxicity. Phenotypic assays for DPD function have been proposed as alternative or complementary approaches to identify DPD deficiencies with the rationale that they may capture unrecognized causes. These assays include the direct measurement of DPD activity in peripheral blood mononuclear cell (PBMC) lysates and measuring plasma metabolites uracil (U), dihydrouracil (UH 2 ), and the dihydrouracil/uracil (UH 2 :U) ratio. We evaluated correlations between PBMC DPD activity and plasma metabolite measures in matched samples from 203 patients with available DPYD exome sequencing data. We also compared the ability of phenotypic measures to identify carriers of deleterious DPYD variants. In addition to established high‐risk variants, we identified three rare DPYD variants predicted to be deleterious: c.274C>G, c.966C>A, and c.1435G>A. Collectively, these variants were associated with impaired DPD function with effect sizes comparable to well‐studied toxicity‐associated variants. At the population level and within carriers of specific genotypes, weak but significant correlations were observed between PBMC DPD activity and either UH 2 :U ratio or U level. These findings suggest that although phenotypic assays can detect severe DPD deficiency, high variability limits their utility as standalone diagnostic tools. Integration with genetic testing may provide a more robust pretreatment risk assessment strategy.

BACKGROUND Hypertrophic olivary degeneration (HOD) is a rare form of transsynaptic degeneration caused by disruption of the dentato-rubro-olivary pathway (Guillain-Mollaret triangle). It is most described following surgical intervention or acute hemorrhagic injury affecting that pathway. However, longitudinal imaging documenting the natural progression of HOD in patients with brainstem cerebral cavernous malformations (CCMs) remains sparsely described at the individual patient level. OBSERVATIONS The authors present the case of a 70-year-old woman with a pontine CCM followed longitudinally over 4 years. Initial imaging demonstrated a right-sided pontine lesion with unilateral HOD in the absence of symptoms. Over time, the CCM enlarged and extended across the midline, coinciding with the development of bilateral HOD and delayed onset of gait imbalance and palatal myoclonus. No surgical intervention was performed. LESSONS In this case, the radiographic evolution from unilateral to bilateral involvement occurred concurrently with the delayed clinical manifestation of HOD. https://thejns.org/doi/10.3171/CASE26577

Diffuse B-cell lymphomas are the most prevalent canine hematologic malignancies, and their clinical presentation resembles that of human B-cell non-Hodgkin lymphomas (NHLs). However, a lack of a clear subtyping framework perpetuates imprecise treatment approaches that fail to address mechanisms of therapy resistance. Here, we employed deep phenotyping via serial sampling and longitudinal transcriptomics to evaluate intratumoral composition and therapy response in a 6-year-old neutered male goldendoodle with stage 5A marginal zone lymphoma (MZL). Following sequential treatment consisting of a single IV dose of oncolytic vesicular stomatitis virotherapy (VSV) and standard CHOP chemotherapy 30 days later, we performed scRNAseq on seven serial lymph node biopsies and spatial sequencing on a resection taken 10 days post-VSV treatment. B cells (>90%) comprised three transcriptionally distinct and temporally stable subpopulations, with specific copy number profiles and robust spatial organization despite disrupted lymph node architecture. Analysis across subpopulations revealed downregulation of the quiescence program including KLF2, suggesting similarity to KLF2-deficient human MZL. While VSV successfully reached target B cells, downstream transcriptional responses were predominantly localized to the T-cell compartment. T cells (≤6%) showed increased proliferation and upregulation of cytotoxicity markers post-VSV administration, enriching for leukocyte-mediated cytotoxicity pathways consistent with an anti-viral immune response. Ultimately, these results provide an in vivo proof-of-concept for the treatment paradigm in canine lymphoma, while emphasizing the need for improved subtyping frameworks and multidimensional treatment strategies targeting intratumoral heterogeneity.

ABSTRACT Background Family history of pancreatic cancer (PC), pathogenic germline variants (PGVs), and increased intrapancreatic fat (IPF) are individually associated with increased PC risk. Whether IPF is elevated in high‐risk individuals (HRIs) with PC family history or PGVs is unknown. Although MRI is the preferred modality for IPF measurement, region‐of‐interest–based approaches are prone to sampling bias because pancreatic fat is heterogeneously distributed. We aimed to compare IPF among HRIs and matched non‐HRI controls using an Artificial intelligence (AI)‐based tool for whole pancreatic IPF measurement applied to magnetic resonance imaging (MRI). Methods We developed and validated a deep‐learning pipeline for IPF measurement that incorporates automated pancreas segmentation on T1‐weighted MRI images registered to the corresponding iterative decomposition of water and fat with echo asymmetry and least squares estimation images to compute IPF using proton density fat fraction (PDFF). This pipeline was used to quantify IPF and assess IPF distribution patterns in 85 HRIs and 170 non‐HRIs matched 1:2 for age, sex, BMI, and diabetes status. A surface erosion approach was developed to minimize the impact of peripancreatic fat on IPF measurement. Linear models adjusting for matching variables were used to assess associations. Results Model‐expert agreement for whole‐pancreas PDFF was excellent (intraclass correlation coefficient 0.99; 95% CI, 0.98–0.99 mean absolute error 1.4%). Mean PDFF did not differ between HRIs and controls (25.8% [11.5] vs. 26.9% [11.4]; p = 0.32). PDFF increased with age ( p = 0.015), male sex ( p < 0.001), presence of diabetes ( p = 0.009), BMI ( p < 0.001). IPF distribution patterns did not differ by risk group. Conclusion An AI‐based approach provides accurate, scalable, and objective assessment of IPF quantity and distribution. IPF quantity and spatial distribution do not appear to differ based on germline or familial predisposition to PC.

Abstract Objective To assess the efficacy and safety of fenfluramine in patients with Dravet syndrome (DS) stratified by age, number of previously attempted antiseizure medications (ASMs), and SCN1A pathogenic variant status. Methods In this post hoc analysis, data from three randomized controlled trials (RCTs) in patients with DS (2–18 years) were pooled and stratified by age (<4; ≥4 years), number of previous ASMs (1–3; 4–6; ≥7), and SCN1A pathogenic variant status ( SCN1A +; SCN1A −). Stratified groups were assessed and compared with the pooled placebo group (change in monthly convulsive seizure frequency [MCSF], longest convulsive seizure‐free interval, and Clinical Global Impression–Improvement [CGI–I] scale scores rated by parents/caregivers and investigators), and safety (treatment‐emergent adverse events [TEAEs]: frequency, days to onset, and proportion resolved). Results Among 348 patients included in the RCTs, 216 were randomized to fenfluramine (0.7 mg/kg/day, n = 88; 0.4 mg/kg/day [with stiripentol], n = 43; 0.2 mg/kg/day, n = 85) and 132 to placebo. Compared with placebo, fenfluramine treatment (all doses combined) resulted in greater MCSF reductions, greater increases in longest convulsive seizure‐free intervals, and a higher proportion of parents/caregivers and investigators reporting clinically meaningful improvement (“Much Improved”, “Very Much Improved”) on CGI–I scores across all stratified groups. CGI–I scores were consistent across fenfluramine doses in most stratified groups, but patients with the fewest number of previous ASMs had the greatest frequency of clinically meaningful improvement on investigator‐rated CGI–I scores. Safety outcomes were similar across all strata. Most TEAEs resolved by end‐of‐study. Significance Fenfluramine treatment was associated with improved seizure outcomes and global functioning compared with placebo regardless of age, number of previous ASMs, and SCN1A status in patients with DS. Fenfluramine was well‐tolerated; no new safety signals were identified. Further studies with larger sample sizes (including adults) and a priori inferential analyses of stratified groups are warranted. Plain Language Summary Patients with Dravet syndrome struggle with seizures and everyday life. In three studies, patients aged 2–18 years received fenfluramine or placebo (sugar pill). Fenfluramine lowered seizures without many side effects. Researchers combined results from these studies to see how fenfluramine worked in different patient groups based on age, number of previous medications, and a gene called SCN1A . They looked at seizure reduction and whether doctors felt patients had improved. In all groups, fenfluramine worked better than placebo, with similar side effects. Researchers believe fenfluramine helped these patients, but some groups were small, so these results need to be confirmed.

Introduction/Objective Opportunistic salpingectomy (OS) has been shown to reduce high-grade serous ovarian cancer (HGSOC) by 42-80%, yet awareness of this strategy outside of obstetrics and gynecology remains limited. The objective of this study was to assess awareness and counseling practices regarding OS for HGSOC prevention among primary care providers (PCPs). Methods We conducted a cross-sectional survey study using a 6-item electronic survey evaluating PCP knowledge and counseling practices related to HGSOC prevention through OS. The study was conducted at a single tertiary care center with gynecologic oncology services. Survey items assessed awareness of HGSOC origin, awareness of OS as a preventative strategy, counseling frequency in the setting of abdominal or pelvic surgery, counseling comfort, and resources needed to increase confidence in recommending OS. Response formats included Likert scales and Yes/No/Unsure options. The survey was distributed by email to attending physicians and advanced practice providers (APPs) in the Department of Family Medicine (FM) and Internal Medicine (IM). Results Of 398 providers surveyed, 136 responded (34% overall response rate; FM 44%, IM 28%), including 96 attending physicians and 40 APPs. Most PCPs were unaware that HGSOC originates in the fallopian tubes (60%) and were unaware of OS as a preventive strategy (71%). Counseling was uncommon: 11% had ever counseled on OS, while 74% had not and 15% reported it was outside their scope. Most respondents (63%) reported being not at all comfortable counseling patients about OS. Providers identified clinical guidelines (60%), CME or training modules (50%), eligibility criteria (48%), gynecology collaboration pathways (48%), and patient-friendly materials (44%) as key supports to improve counseling confidence. Conclusion PCP awareness and counseling regarding OS are limited. Given that guideline support for OS has solidified only in recent years, these gaps are not surprising—and they represent a clear, actionable opportunity. PCPs are well-positioned to lead the expansion of ovarian cancer prevention beyond specialty care with the right tools and support.

Abstract Colorectal cancer develops through a normal-adenoma-carcinoma sequence, yet only 5-10% of adenomas progress to malignancy, and the cellular programs governing that sequence remain poorly defined. Here we generate a spatial multi-omics atlas of human colon adenomas, combining Visium CytAssist and protein co-detection across 24 nonadvanced and advanced tubular adenomas with single-cell resolution Xenium Prime 5K profiling of 101 patient-matched normal, adenoma, and carcinoma cores from 16 patients. Integrating whole-transcriptome and 31-plex protein data identifies nine spatial clusters and two dysplastic epithelial populations that co-express stemness, proliferation, and senescence programs. These programs occupy a shared, spatially confined epithelial niche that expands from adenoma to carcinoma. Spatial analysis revealed GDF15, a senescence-associated secretory factor, mediated the coupling between senescence and stemness in advanced adenomas, and that GDF15-high epithelium locally excludes CD8+ T cells in adenoma and, more broadly, in carcinoma. These findings position senescence as a spatially instructive rather than merely tumor-suppressive program during colorectal carcinogenesis and suggest GDF15 might be a potential candidate target for cancer prevention and interception in the colon.

The Clinical Pharmacogenetics Implementation Consortium (CPIC) TPMT/NUDT15 Pharmacogene Curation Expert Panel (PCEP) conducted a comprehensive review of clinical, laboratory, and computational evidence to determine the clinical function assignments for TPMT and NUDT15 star alleles. These genes are critical for the metabolism of thiopurines, which are widely used in the treatment of cancer and autoimmune disorders. Standardized allele function assignment is essential for predicting metabolizer phenotypes and pharmacogenetics‐guided thiopurine dosing. The work presented here includes the first designation of decreased function alleles for both TPMT and NUDT15 , reflecting new clinical data that demonstrate partial loss of enzymatic activity and reduced dose tolerance. The panel also reclassified several alleles previously assigned uncertain or unknown function. The functional assignments were informed by a standardized framework incorporating clinical data, such as thiopurine tolerance and toxicity, as well as in vitro protein activity, ex vivo enzymatic measurements, and in silico variant effect prediction tools. These updates enhance the precision of genotype‐to‐phenotype mapping and support more personalized thiopurine therapy across diverse patient populations.

Pediatric sarcomas are a heterogeneous group of rare mesodermal malignancies. These cancers, which affect children from infancy through adolescence and young adulthood, are in general challenging to treat with currently available therapies. Biologically, many are characterized by quiet genomes, fusion oncoproteins, immune “cold” microenvironments, and vast epigenetic deregulation that contributes to diverse and complex mechanistic drivers. Multifaceted advancements in research strategies, including high-throughput screening, new model systems, surfaceome profiling, and study of oncogenic fusion condensates have led to new opportunities for understanding the biology of pediatric sarcomas. To continue to make progress for these difficult to treat cancers, it will be critical to continue to improve access to bioinformatic data, approach patient care using innovative clinical trial frameworks, and foster interdisciplinary partnerships among medicinal chemists, scientists, clinicians, advocates, and industry partners.