Citations

Abstract INTRODUCTION Determining apolipoprotein E ( APOE ) ε4 allele status, a key genetic risk factor for Alzheimer's disease (AD), requires molecular genotyping infrastructure not widely accessible beyond specialized centers. METHODS A fully automated high‐throughput apoE E4 proteotyping immunoassay was evaluated for clinical performance (460 participants across three cohorts) and analytical validity. Concordance with polymerase chain reaction (PCR)‐based genotyping and measures of analytical validity were reported. RESULTS The apoE E4 immunoassay demonstrated 99.6% (95% confidence interval [CI]: 98.4% to 99.9%) concordance with PCR‐based APOE ε4 genotype results across the pooled clinical cohort; 100.0% (95% CI: 97.1% to 100.0%) in those with AD ( N = 127) and 99.4% (95% CI: 97.8% to 99.8%) in those without AD (333). The assay met analytical validity criteria for E4 isoform specificity, interference, precision, and stability. DISCUSSION The apoE E4 immunoassay demonstrated high concordance with PCR‐based genotyping and robust analytical validity, offering an accessible alternative for APOE ε4 zygosity assessment. Highlights A novel high‐throughput plasma‐based proteotyping immunoassay for APOE ε4 zygosity classification was developed and evaluated for clinical performance and analytical validity. The apoE E4 immunoassay demonstrated high concordance (99.6%) with PCR‐based APOE ε4 genotyping across a diverse international cohort, and a robust analytical profile. An apoE E4 immunoassay may offer a more cost‐effective and accessible alternative to DNA genotyping approaches currently used for AD risk evaluation and anti‐amyloid treatment decisions.

Abstract Current assessments of brain permeability rely predominantly on drug delivery to contrast-enhancing tumor regions. However, substantial portions of central nervous system (CNS) tumors reside within non-enhancing brain (NEB), where drug concentrations frequently remain subtherapeutic. This collaborative Adult Brain Tumor Consortium and Food and Drug Administration workshop aimed to identify criteria for defining NEB permeability to accomplish 2 critical objectives: (1) allocate clinical trial resources toward agents achieving therapeutic NEB concentrations and (2) minimize systemic toxicity when CNS benefit is improbable. The workshop systematically evaluated permeability assessment modalities, including drug physicochemical properties, in vitro blood-brain barrier models, and penetration into cerebrospinal fluid and normal rodent brain. Methodological approaches to determine requisite NEB drug concentrations and approaches to measuring NEB pharmacokinetics and pharmacodynamics were examined. This culminated in developing the Non-Enhancing Brain Permeability Index (NEBPI), which assigns therapeutic agents to 3 categories: sufficiently permeable, insufficiently permeable, or impermeable. The NEBPI provides a standardized framework to assist investigators and regulatory agencies to evaluate NEB penetration before human efficacy studies are initiated for agents that require direct tumor contact. Assessing NEB drug penetration is critical to improving outcomes in CNS tumors and reducing the incidence of brain metastases in systemic malignancies.

Abstract Insulinoma is the most prevalent neuroendocrine tumor of the pancreas, presenting with a spectrum of neuroglycopenic symptoms. This case report describes a 64-year-old woman with primarily postprandial hypoglycemia, resulting in altered consciousness and confusion occurring several hours after meals. Continuous glucose monitoring (CGM) was used to establish the postprandial pattern of the patient's hypoglycemia, and this facilitated the confirmatory biochemical evaluation by a single blood draw done at the time of symptoms, without performing a 72-hour fast. Imaging demonstrated an 11-mm tumor in the pancreas, which was removed and confirmed to be a well-differentiated neuroendocrine tumor on histopathology. While awaiting pancreatic surgery, the patient began taking melatonin for sleep and reported an improvement in the frequency and severity of hypoglycemia symptoms, which was supported by CGM data and a robust expression of melatonin receptors on the excised tumor. This case raises interest in the role of melatonin receptor signaling in counteracting hyperinsulinemia and corresponding hypoglycemia in patients with insulinoma.

Abstract Objectives Diagnosing adult T-cell leukemia/lymphoma (ATLL) remains challenging due to its clinical and histopathologic heterogeneity. While HTLV-1 serology is a key diagnostic criterion, it is often unavailable at the time of diagnosis and does not confirm viral integration in tumor cells. The HTLV-1–encoded HBZ RNA is a reliable diagnostic biomarker for ATLL. We evaluated the diagnostic performance of RNAscope in situ hybridization (ISH) for HBZ RNA in formalin-fixed, paraffin-embedded (FFPE) tissues to distinguish ATLL from other T-cell lymphomas. Methods HBZ ISH was evaluated in 72 cases, including 52 ATLLs and 20 non-ATLL T-cell lymphomas, to determine diagnostic sensitivity and specificity, interobserver agreement, interlaboratory reproducibility, and comparison with digital gene expression. Results This assay demonstrated 86.5% sensitivity and 100% specificity, with sensitivity improving to 97% when excluding bone marrow clot sections and FFPE blocks older than 5 years. Interobserver agreement among 3 pathologists was excellent (κ = 0.92, percent agreement: 94%). Interlaboratory reproducibility of HBZ ISH was high, with 93% to 95% concordance across these Clinical Laboratory Improvement Amendments–certified laboratories. HBZ RNA ISH–positive cases demonstrated significantly higher HBZ gene expression levels by digital gene expression profiling. Conclusions We established HBZ ISH as a reliable tissue-based surrogate for HTLV-1 infection in ATLL. This assay will enhance diagnostic accuracy, expedite definitive diagnosis, and improve patient selection for targeted therapies and clinical trials, particularly in regions with a high prevalence of HTLV-1.

Abstract Objectives Traditional laboratory regulatory frameworks provide robust guidance for conventional clinical testing but lack requirements for data documentation for artificial intelligence and machine learning (AI/ML) solutions. This gap creates significant risks since AI solutions directly inherit patterns, biases, and limitations from their training data. Here, we describe the development and implementation of a comprehensive data documentation checklist with accompanying data lineage for use within an AI lifecycle framework for clinical laboratories. Methods Building on the previously established Clinical AI Readiness Evaluator (CARE) framework, we developed a comprehensive data checklist and data lineage methodology through a multiphase process, including (1) comprehensive review of existing AI/ML data documentation frameworks, (2) focused meetings with 3 institutional AI operations teams, and (3) 3 rounds of iterative refinement by our multidisciplinary team. The checklist’s effectiveness was then assessed using 3 diverse AI/ML projects moving through the CARE framework. Results The CARE Data Checklist and Data Lineage provide a structured approach to documenting critical aspects of datasets used in AI/ML projects, including data composition, demographics, collection methods, labeling processes, usage constraints, maintenance requirements, and a data readiness assessment. The checklist addresses unique data-centric challenges of AI/ML applications, facilitating transparency, reproducibility, and regulatory compliance. Conclusions The CARE Data Checklist and Data Lineage serve as both a technical guide and a communication tool bridging gaps between technical and clinical stakeholders. By working on these documents early in the AI lifecycle, laboratories can anticipate and address data-related challenges, ultimately saving time, optimizing resources, and improving the reliability of AI-augmented laboratory solutions.

OBJECTIVE Electrical stimulation mapping is a widely used technique to determine functional localization for medically refractory epilepsy. Sites where stimulation interferes with naming are often focal regions of the frontal and temporal cortex. The extent to which these crucial sites remain in the same location over time in an individual adult patient has not yet been established. The aim of this study was to determine whether cortical naming sites identified using stimulation mapping are stable in their anatomical location over time in adult patients with medically refractory epilepsy. METHODS Twenty-two patients who underwent electrical stimulation mapping for medically refractory epilepsy during surgical interventions separated by more than 1 year between 1967 and 2005 were included. A median of 8.35 years elapsed between mappings. The mean age at the first operation was 27.7 (range 10–39) years. Fourteen patients were female. Mapping occurred under two different conditions: intraoperatively in procedures conducted under local anesthesia or extraoperatively through implanted grid electrodes. A Bayesian hierarchical model of language site locations across repeated interventions was used to assess the stability of locations of stimulation-evoked interference in language naming. RESULTS Sites where electrical stimulation interferes with language naming were separated by a median of 0.6 cm between the 2 mappings. Eighty-six percent of the mapped sites related to language naming at the second operation were within 1.5 cm of a site identified at the first operation, 61% within 1 cm, and 36% within 0.5 cm. However, in 2 patients, none of the identified language naming sites at the second operation were within 1.5 cm of the sites from the first operation. CONCLUSIONS This unique, long-term series of neurosurgical mappings reveals that language naming sites in the cortex of adult patients with epilepsy show substantial long-term stability over many years. However, rare relocation of these sites does occur in some patients over many years.

Abstract Background White matter hyperintensities (WMH) are widely used to assess cerebral small vessel disease (SVD) but reflect late-stage injury. Diffusion MRI based biomarkers have been proposed to capture earlier SVD-related microstructural damage but their temporal progression relative to WMH and the risk factors associated with this progression have not been explored. Methods We analyzed longitudinal neuroimaging data from 2,047 participants from a population-based cohort study (aged 49-101 years, 47% female). Using multi-output nonlinear mixed-effects models, we characterized the temporal progression of WMH and four diffusion MRI based biomarkers: fractional anisotropy of the genu of the corpus callosum (Genu-FA), peak width of skeletonized mean diffusivity (PSMD), free water (FW), and Arteriolosclerosis-score (ARTS). Models incorporated participant-specific time shifts, correlations between biomarkers, and effects of risk factors (sex, education, APOE ε4 status, and cardiometabolic conditions). Results ARTS, Genu-FA, FW, and PSMD became abnormal in 50% of the study population 16, 12, 10, and 7 years before WMH, respectively. Global markers (ARTS, FW, PSMD, WMH) were correlated, indicating shared substrates of widespread white matter injury. Genu-FA, a vascular risk microstructural injury biomarker, was weakly coupled with WMH and had an earlier but more linear worsening across adulthood. Cardiometabolic conditions predicted earlier worsening of all biomarkers. Females showed earlier WMH, Genu-FA, and ARTS abnormalities whereas males exhibited earlier PSMD and FW abnormalities. Conclusions Diffusion MRI based biomarkers capture microstructural injury at least a decade before appearance of WMH, revealing a prolonged phase of early SVD and highlighting their potential for SVD prevention.

Abstract Extra-axial chordoma (EAC) is a very rare, malignant tumor with metastatic potential that arises in the extra-axial skeleton and soft tissues. We report the case of a 51-year-old right-handed male with EAC of the left capitate. He underwent capitate resection and wrist arthrodesis utilizing scaphoid autograft with the treatment goal of minimizing risk of tumor recurrence and metastasis while maximizing hand and wrist function. His radiographic outcome demonstrated union of his arthrodesis site. However, 7 months postoperatively, he started experiencing increased hand and wrist pain and was found to have early tumor reoccurrence. Few cases of EAC have been reported in the literature. EAC is typically treated with resection alone, although there is a limited role for chemotherapy and radiation in the setting of locally reoccurring or metastatic disease. Functional outcomes of the affected extremity and survival outcomes vary widely. This is the first report in the literature of EAC of a single carpal bone and describes an innovative technique for definitive surgical treatment of this rare tumor. Utilization of scaphoid autograft for wrist arthrodesis in the setting of capitate resection allows the use of autograft in a wrist arthrodesis without the additional morbidity of iliac crest bone grafting. This case also demonstrates the importance of appropriate diagnosis and oncologic technique at the index surgery.