Astroblastomas exhibit radial glia stem cell lineages and differential expression of imprinted and X-inactivation escape genes [methylation]
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ABSTRACT: Astroblastoma (AB) is an unusual brain tumor of unknown origin. We performed an integrated clinicogenomic analysis of 36 AB-like tumors. Lesions with MN1-BEND2 fusions demonstrated decreased promoter methylation and increased expression of IGF2-H19 and DLK1-DIO3 imprinted region genes. They also relatively overexpressed genes highly expressed during fetal brain development prior to 25 post-conception weeks (pcw), including genes enriched in ventricular zone radial glia (vRG), and generally presented in young children. Other tumors highly expressed MAP kinase pathway, PI3K pathway and X-inactivation escape genes. These and a third group of tumors tended to occur in young adults and showed enriched expression of outer radial glia (oRG) and truncated radial glia (tRG) genes, and genes highly expressed after 25 pcw. Many of the latter are involved in axonal migration or synaptic plasticity and are implicated in autism, schizophrenia and other cognitive disorders. Findings suggest that AB-like tumors arise in the context of epigenetic and genetic changes in neural progenitors during fetal and later brain development: early ependymal tumors with MN1-BEND2 fusions (EET-MN1) from vRG-derived progenitor cells, and MAPK/PI3K and classic astroblastomas from oRG- and tRG-derived progenitors, respectively. Lastly, we found that like EET-MN1, immature ependymal cells express IGF2 and may represent an important source of this growth factor in the fetal lateral ventricular zone neural stem cell niche.
ORGANISM(S): Homo sapiens
PROVIDER: GSE166569 | GEO | 2022/02/20
REPOSITORIES: GEO
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