Ganglioglioma is a tumor of neuroepithelial tissue that arises from ganglion cells in the central nervous system.
They are mixed tumors that contain both glial and neuronal elements.
Pathological Examination: The biopsy sample is analyzed by a pathologist who specializes in diagnosing tumors. They will examine the cells and tissue architecture to confirm the presence of ganglion cells and glial cells characteristic of ganglioglioma. Additional molecular testing may be performed to provide further information about the tumor.
Grading and Staging: Once the diagnosis of ganglioglioma is confirmed, the tumor is usually assigned a grade based on its appearance and cellular characteristics. Gangliogliomas are typically classified as World Health Organization (WHO) grade I or II, indicating low-grade tumors with a generally good prognosis. Staging is not typically performed for gangliogliomas since they are usually localized tumors.
Gangliogliomas are often characterized by a rare population of immature astrocyte-appearing cells expressing CD34, a marker expressed in the neuroectoderm (neural precursor cells) during embryogenesis. New insights are needed to refine tumor classification and to identify therapeutic approaches. Regal et al. evaluated five gangliogliomas with single nucleus RNA-seq, cellular indexing of transcriptomes and epitopes by sequencing, and spatially-resolved RNA-seq. They uncovered a population of CD34+ neoplastic cells with mixed neuroectodermal, immature astrocyte, and neuronal markers. Gene regulatory network interrogation in these neuroectoderm-like cells revealed control of transcriptional programming by TCF7L2/MEIS1-PAX6 and SOX2, similar to that found during neuroectodermal/neural development. Developmental trajectory analyses place neuroectoderm-like tumor cells as precursor cells that give rise to neuron-like and macroglia-like neoplastic cells. Spatially-resolved transcriptomics revealed a neuroectoderm-like tumor cell niche with a relative lack of vascular and immune cells. They used these high-resolution results to deconvolute clinically-annotated transcriptomic data, confirming that CD34+ cell-associated gene programs are associated with gangliogliomas compared to other glial brain tumors. These deep transcriptomic approaches characterized a ganglioglioma cellular hierarchy-confirming CD34+ neuroectoderm-like tumor precursor cells, controlling transcription programs, cell signaling, and associated immune cell states. These findings may guide tumor classification, diagnosis, prognostication, and therapeutic investigations 1)