Biomedical subjects

Andreas von Deimling

Publications and source records attributed to Andreas von Deimling.

3 recordsLinked to original sources

PubMed2026

Primary mismatch repair deficient glioma, IDH-wildtype and H3-wildtype: A giant cell tumor with potential for long-term survival occurring at all ages.

BACKGROUND: Replication repair deficiency is associated with increased risk of developing malignant gliomas. The aim of this study was to investigate primary mismatch repair deficient gliomas (PMMRDGs), a group of IDH-wildtype and H3-wildtype gliomas that is enriched among patients with CMMRD and Lynch syndrome. METHODS: We investigated how PMMRDGs differ from other gliomas with respect to DNA methylation profile, genomic alterations, histopathology, and clinical outcomes. RESULTS: PMMRDGs occur in pediatric, adolescents and the elderly, falling in two related methylation clusters and are characterized by a high frequency of replication repair deficiency. Histology showed multinucleated giant cells, and immunohistochemistry demonstrated loss of MMR protein expression. Survival analysis revealed long-term survival in patients with high mutational burden (>50 mut/Mb) and an intact chromosome 9p region, which was validated in an independent reference cohort. CONCLUSIONS: Overall, our findings indicate that PMMRDGs represent a distinct type of IDH-wildtype gliomas with potential for long-term survival likely driven by immune activation.

Humans↗

PubMed2026

Integrated Clinicopathologic and Multiomic Profiling Reveals MEIS1-Rearranged Sarcoma as a Distinct Entity With 2 Prognostic Subgroups.

Sarcomas with MEIS1 fusions represent a rare, recently recognized group of mesenchymal neoplasms with a predilection for genitourinary and gynecologic sites. A subset exhibits skeletal muscle differentiation resembling spindle cell rhabdomyosarcoma. Existing literature is limited to case reports and small series, with scant comprehensive clinicopathologic, molecular, and outcome data. In this study, we analyzed a multi-institutional cohort of 20 MEIS1-rearranged sarcomas using integrated clinicopathologic review, genomic profiling, and DNA methylation analysis. The tumors occurred in 17 females and 3 males (median age, 41 years; range, 6-58 years), arising mainly in the uterus/vagina (n = 12), vulva/perineum (n = 4), bone (n = 2), and kidney (n = 2), with a median size of 9 cm (range, 2.5-20 cm). Histology showed mostly bland spindle cells in fascicles/storiform patterns, alternating cellularity, fibromyxoid stroma, prominent vascularity, and adipose metaplasia (45%). A subset of cases featured high-grade morphology with epithelioid cells and increased mitotic activity. Skeletal muscle markers were variably positive in 9 cases. Fusions involved MEIS1 with NCOA2 (16/20), NCOA1 (3/20), or FOXO1 (1/20). Recurrent additional genomic alterations included CTNNB1 mutations (31.6%) and MDM2 amplification (15%). DNA methylation profiling showed that MEIS1-rearranged sarcomas formed a unifying cluster comprising 2 subgroups, regardless of rhabdomyosarcomatous phenotype, clearly separated from other mesenchymal neoplasms, including various rhabdomyosarcoma subtypes and uterine sarcomas. The 2 DNA methylation (Meth) subgroups correlated with differences in genome-wide copy number variation (CNV) status (Meth-CNV high vs Meth-CNV low), with Meth-CNV high tumors characterized by high mitotic rate, frequent tumor necrosis, recurrent co-occurring CTNNB1 and MDM2 alterations, and recurrent chromosomal arm-level changes. Most importantly, this subgroup exhibited significantly worse overall survival (P = .027) and disease-free survival (median, 5 vs 99 months; P = .017). This study establishes MEIS1-rearranged sarcoma as a distinct entity with generally indolent but potentially aggressive behavior. The 2 methylation/CNV subgroups provide potential utility for prognostic stratification and highlight actionable molecular targets in high-risk cases.

Humans↗

PubMed2025

Individualized patient tumor organoids faithfully preserve human brain tumor ecosystems and predict patient response to therapy.

Tumor organoids are important tools for cancer research, but current models have drawbacks that limit their applications for predicting response to therapy. Here, we developed a fast, efficient, and complex culture system (IPTO, individualized patient tumor organoid) that accurately recapitulates the cellular and molecular pathology of human brain tumors. Patient-derived tumor explants were cultured in induced pluripotent stem cell (iPSC)-derived cerebral organoids, thus enabling culture of a wide range of human tumors in the central nervous system (CNS), including adult, pediatric, and metastatic brain cancers. Histopathological, genomic, epigenomic, and single-cell RNA sequencing (scRNA-seq) analyses demonstrated that the IPTO model recapitulates cellular heterogeneity and molecular features of original tumors. Crucially, we showed that the IPTO model predicts patient-specific drug responses, including resistance mechanisms, in a prospective patient cohort. Collectively, the IPTO model represents a major breakthrough in preclinical modeling of human cancers, which provides a path toward personalized cancer therapy.

Humans↗