Abstract INTRODUCTION The infectious hypothesis suggests that microbes like herpesviruses may play a role in the pathogenesis of Alzheimer's disease (AD) and other related dementias through methods that may include viral genome integration. The occurrence of herpesvirus genome integration in dementia patients has not been thoroughly characterized. METHODS Over 7500 total whole‐genome sequences from control, frontotemporal dementia/amyotrophic lateral sclerosis spectrum, Lewy body dementia (LBD), multiple system atrophy (MSA), and AD cohorts were screened for the integration of pathogen genomes using the PathSeq computational tool. RESULTS Low PathSeq scores for human herpesvirus 6 (HHV‐6) were consistent with the suspected integration of viral genome segments. The LBD and MSA cohorts had a significantly higher prevalence of this partial HHV‐6 genome integration. DISCUSSION This higher prevalence in both synucleinopathies was not noted in other herpesviruses, suggesting that the integration of HHV‐6 may play a role in a subset of these patients. Highlights Over 7500 whole‐genome sequences from controls and dementia patients were analyzed. Sequences consistent with integrated herpesviruses were identified using PathSeq. Prevalence of partial HHV‐6 integration was higher in synucleinopathies. Herpesviruses genome integration may play a role in subsets of dementia patients.
Neoadjuvant Immunotherapy and Chemoimmunotherapy Regimens in Head and Neck Cancer
IMPORTANCE Neoadjuvant chemoimmunotherapy has high rates of pathologic response and improved prognosis among solid tumors. Its role in head and neck squamous cell carcinoma (HNSCC) remains understudied. OBJECTIVE To summarize the efficacy associated with neoadjuvant chemoimmunotherapy regimens in HNSCC and to compare the efficacy associated with neoadjuvant chemoimmunotherapy vs immunotherapy alone in locoregionally advanced resectable HNSCC prior to definitive surgery. DATA SOURCES A librarian-led systematic review was conducted using multiple electronic databases, including Medline, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Scopus, following Preferred Reporting Items for Systematic Reviews and Meta- Analyses (PRISMA) guidelines. Databases were queried from inception to October 2024. STUDY SELECTION Inclusion criteria included prospective interventional trials that have completed accrual, with results published in English. Only trials of resectable, treatment-naive HNSCC were included. Exclusion criteria included lack of reporting on pathologic response or Response Evaluation Criteria In Solid Tumors (RECIST) version 1.1 response. DATA EXTRACTION AND SYNTHESIS Two investigators independently conducted title, abstract, and full-text reviews per PRISMA guidelines. Primary outcomes extracted were major pathologic response (MPR) and complete pathologic response (CPR) at surgery and complete response (CR) on imaging by RECIST 1.1. Secondary outcomes included 1-year overall survival (OS) and toxic effects. MAIN OUTCOMES AND MEASURES A meta-analysis was performed using a binary random-effects model to determine the pooled proportion of primary outcomes in the immunotherapy and chemoimmunotherapy groups. Heterogeneity was reported as I 2 . RESULTS A total of 751 patients (502 [77%] male; age range, 27-87 years) across 23 studies were included in the meta-analysis, including 357 patients (47%) who underwent chemoimmunotherapy, 102 patients (14%) who underwent dual-agent immunotherapy, and 292 patients (39%) who underwent single-agent immunotherapy. Pooled rates of MPR plus CPR were 66% (95% CI, 58%-73%; I 2 = 0.59) for chemoimmunotherapy, 18% (95% CI, 6%-29%; I 2 = 0.65) for dual-agent immunotherapy, and 6% (95% CI, 3%-9%; I 2 < 0.01) for single-agent immunotherapy. Across all groups, 1-year OS rates ranged from 88% to 96% for single-agent immunotherapy, 88% to 96% for dual-agent immunotherapy, and 88% to 100% for chemoimmunotherapy. Grade 3 to 5 adverse events were reported in 61 of 210 patients (29%), 2 of 67 patients (3.0%), and 36 of 210 patients (17%) among the reporting studies in the single-agent immunotherapy, dual-agent immunotherapy, and chemoimmunotherapy groups, respectively. CONCLUSIONS AND RELEVANCE These findings suggest that neoadjuvant chemoimmunotherapy regimens were associated with higher pathologic and radiographic response rates compared with immunotherapy alone in locoregionally advanced HNSCC. These results call for phase 3 trials comparing these neoadjuvant regimens head to head.
CNSC-02. Investigating the Evolution of Neuron-Glioma Circuit Dynamics
Abstract Pediatric high-grade gliomas (pHGG) are aggressive primary brain neoplasms with a dismal prognosis, making them the leading cause of brain tumor-related deaths in children. pHGGs occur in specific anatomical locations at specific ages underscoring their origin in neurodevelopment and the critical importance of the brain tumor microenvironment. Many pHGGs originate from oligodendroglial precursor cells (OPC) and, like OPCs, neuronal activity promotes pHGG proliferation. Neuronal activity drives pHGG growth through the secretion of activity-regulated mitogens and electrochemical communication with pHGG cells that integrate into neural circuits. In turn, pHGG increases neuronal excitability and remodels functional neural circuits. The interconnected network of glioma cells and neurons is fundamental to pHGG progression. We developed a two-color in vivo imaging method to study neuron-glioma cell interactions over time in freely behaving mice enabling us to record the frequency, pattern, and synchronicity of calcium transients in neurons, glioma cells, and their coactivity, giving us a comprehensive view of the changes in neuron-glioma circuit dynamics over time. Our imaging paradigm offers a unique ability to study neuron-glioma interactions at the systems level. We have observed increasing neuronal activity and synchronicity throughout the disease. We have also observed that different gliomas exhibit unique patterns of calcium transients and show increased levels of activity and synchronicity as the tumor progresses. We verified our findings through longitudinal in vivo local field potential recordings, finding an increase in all power bands, especially in high-gamma activity over time. Using single nuclei RNA sequencing of mice harboring murine H3K27M-altered DMG, we observed gene expression changes indicating an increase in synaptogenesis and axonogenesis processes in glioma-associated neurons. Performing in vitro neurite outgrowth assays, we observed increased axonogenesis in hiPSC-derived neurons in the presence of pHGGs compared to other neurons, confirming our snRNA-seq findings. Based on this data, we hypothesize that as gliomas progress, the neuron-glioma malignant circuitry evolves through synaptogenesis and axonogenesis to promote glioma progression.