Project description:Meningiomas are the most common primary brain tumor. Though typically benign with a low mutational burden, histopathologic analysis has poor predictive value for malignant behavior and there are no proven chemotherapies. Although DNA methylation patterns distinguish subgroups of meningiomas and have higher predictive value for tumor behavior than histologic classification, little is known about differences in DNA methylation between meningiomas and surrounding normal dura tissue. Using multimodal studies of meningioma/dura pairs, we identified 4 distinct DNA methylation patterns. Diffuse DNA hypomethylation of malignant meningiomas readily facilitated their identification from lower grade tumors by unsupervised clustering. All clusters and 12/12 meningioma-dura pairs exhibited hypomethylation of the gene promoters of a module associated with the craniofacial patterning transcription factor FOXC1 and its upstream lncRNA FOXCUT. Furthermore, we identified an epigenetic continuum of increasing hypermethylation of polycomb repressive complex target promoters with increased histopathologic grade suggesting progressive epigenetic dysregulation is associated with increasing tumor aggressiveness. These findings are a starting point for future investigations of the role of epigenetic dysregulation of FOXC1 and cranial patterning genes in early stages of meningioma formation as well as studies of the utility of polycomb inhibitors for treatment of aggressive meningiomas.
Project description:Meningiomas are the most common primary brain tumor. Though typically benign with a low mutational burden, histopathologic analysis has poor predictive value for malignant behavior and there are no proven chemotherapies. Although DNA methylation patterns distinguish subgroups of meningiomas and have higher predictive value for tumor behavior than histologic classification, little is known about differences in DNA methylation between meningiomas and surrounding normal dura tissue. Using multimodal studies of meningioma/dura pairs, we identified 4 distinct DNA methylation patterns. Diffuse DNA hypomethylation of malignant meningiomas readily facilitated their identification from lower grade tumors by unsupervised clustering. All clusters and 12/12 meningioma-dura pairs exhibited hypomethylation of the gene promoters of a module associated with the craniofacial patterning transcription factor FOXC1 and its upstream lncRNA FOXCUT. Furthermore, we identified an epigenetic continuum of increasing hypermethylation of polycomb repressive complex target promoters with increased histopathologic grade suggesting progressive epigenetic dysregulation is associated with increasing tumor aggressiveness. These findings are a starting point for future investigations of the role of epigenetic dysregulation of FOXC1 and cranial patterning genes in early stages of meningioma formation as well as studies of the utility of polycomb inhibitors for treatment of aggressive meningiomas.
Project description:Meningiomas, named for their cell of origin, are the most common intracranial tumors in adults, representing 39% of all primary adult central nervous system tumors. These tumors originate in the meninges, which are the outer three layers of tissue between the skull and the brain that cover and protect the brain just under the skull. Most meningioma tumors (85-90 percent) are categorized as benign, with the remaining 10-15 percent being atypical meningioma or malignant meningioma (cancerous). The word “benign” can be misleading for meningiomas. Depending on location and growth rate, a benign meningioma brain tumor may impinge on vital nerves or compress the brain, causing disability. They may even become life threatening. We describe transcriptional signatures of four most common groups of benign meningiomas. Each subgroup of meningiomas displayed a unique gene expression program identifying signaling pathways potentially implicated in the tumorigenesis. These findings will improve our understanding of meningioma tumorigenesis. Objective: To define gene expression signatures of the most common subtypes of meningiomas to better understand cellular processes and signaling pathways specific for each tumor genotype.
Project description:Correlate the gene expression profiles with the most relevant patterns of chromosome abnormalities (cytogenetic subgroups of meningiomas) and the gene expression profiles could help to explain the differences in clinical behaviour of meningiomas. The impact of tumor cytogenetics on the gene expression analyzed in meningiomas. Here, we analyzed the gene expression profiles (GEP) of 47 tumors and correlated them with the most clinical relevant cytogenetic subgroups of meningiomas, including diploid tumors, isolated -22/22q-, del(1p36) alone and complex karyotypes associated with del(1p36) and/or -14q. In addition, 4 samples containing purified RNA extracted from normal meningeal cells (BioChain Institute, Hayward, CA and US Biological, Swampscott, MA, USA) were also processed.
Project description:Correlate the gene expression profiles with the most relevant patterns of chromosome abnormalities (cytogenetic subgroups of meningiomas) and the gene expression profiles could help to explain the differences in clinical behaviour of meningiomas.
Project description:Experiment: Establishment of expression profiles in grade I and grade II meningiomas and in normal control brain samples. We extracted DNA from specimens and performed mutational analysis in meningiomas and extracted RNA that was processed and hybridized to Affymetrix microarrays.