Project description:We carried out the analyses of chromosome variations between low-grade and high-grade gliomas in Chinese population. We found out the differences in chromosomes, cytobands, genes, pathways and GO functions. To identify the glioma tissue-specific genomic alterations and compare the genomic variations between low-grade and high-grade gliomas.
Project description:Pediatric low-grade gliomas (PLGGs) are among the most common solid tumors in children but apart from BRAF mutations or duplications in specific subclasses, few genetic driver events are known. Diffuse PLGGs comprise a set of uncommon subtypes that exhibit invasive growth and are therefore especially challenging clinically. These tumors are particularly poorly understood. We performed high-resolution copy-number analysis of 44 diffuse PLGGs to identify recurrent alterations. Diffuse PLGGs exhibited fewer such alterations than adult low-grade gliomas, but we identified several significantly recurrent events. The most significant event, 8q13.1 gains, were observed in 28% of diffuse astrocytomas grade II (DA2s) and resulted in partial duplication of the transcription factor MYBL1 with truncation of its C-terminal negative-regulatory domain. A similar recurrent deletion-truncation breakpoint was identified in two angiocentric gliomas in the related gene MYB on 6q23.3. Whole-genome sequencing of a MYBL1-rearranged DA2 demonstrated MYBL1 tandem duplication, and few other events. Two novel, truncated MYBL1 transcripts identified in this tumor induced anchorage-independent growth when expressed in 3T3 cells and tumor formation in nude mice. Truncated transcripts were also expressed in two additional tumors with MYBL1 partial duplication. Our results define clinically relevant molecular subclasses of diffuse PLGGs and highlight a potential role for the MYB family in the biology of low-grade gliomas.
Project description:We performed gene expression profiling on 151 paraffin-embedded PLGGs from different locations, ages, histological subtypes as well as BRAF genetic status We also compared molecular differences to normal pediatric brain expression profiles to observe whether those patterns were mirrored in normal brain expression. We analyzed the expression of 6,100 genes among 151 FFPE pediatric and 15 FFPE adult low-grade gliomas and analyzed how the expression patterns changes with location, age, histology and BRAF genomic status and how those differences were mirrored in normal brain expression. The values in the sample 'characteristics' columns represent; Location; SUP= Supratentorial, INF= Infratentorial Histology; PA= pilocytic astrocytoma, GG= ganglioglioma, DNT= dysembryoplastic neuroepithelial tumor, OD= oligodendroglial tumors, NOS= not otherwise specified tumors BRAF status; DUP= BRAF duplication, MUT= BRAF V600E mutation, WT= wild type, ND= not determined Primary or recurrent tumor; P=primary, R=recurrent Primary tumor that further progressed; 1=yes, 0=no, _=recurrent tumors only
Project description:<p>Pediatric low-grade gliomas (PLGGs) are among the most common solid tumors in children but, apart from mutations or duplications in the BRAF kinase in specific subclasses, few genetic driver events are known. Diffuse PLGGs compose a set of uncommon subtypes that exhibit invasive growth and are therefore especially challenging clinically. These tumors are particularly poorly understood. We performed high-resolution copy-number analysis of 44 diffuse PLGGs to identify recurrent alterations. Diffuse PLGGs exhibited fewer such alterations than adult low-grade gliomas, but we identified several significantly recurrent events. The most significant event, 8q13.1 gains, was observed in 28% of diffuse astrocytoma WHO grade II (DA2) and resulted in partial duplication of the transcription factor MYBL1 with truncation of its C-terminal negative-regulatory domain. A similar recurrent deletion-truncation breakpoint was identified in two angiocentric gliomas in the related gene MYB on 6q23.3. Whole genome sequencing of a MYBL1-rearranged diffuse astrocytoma grade II demonstrated MYBL1 tandem duplication and few other events. Two truncated MYBL1 transcripts identified in this tumor induced anchorage-independent growth when expressed in 3T3 cells and tumor formation in nude mice. Truncated transcripts were also expressed in two additional tumors with MYBL1 partial duplication. Our results define clinically relevant molecular subclasses of diffuse PLGGs and highlight a potential role for the MYB family in the biology of low-grade gliomas. "Reprinted from www.pnas.org/cgi/doi/10.1073/pnas.1300252110 with permission from PNAS." </p>
Project description:<p>Pediatric low-grade gliomas (PLGGs) are the most common pediatric brain-tumor, with more than ten histologic subtypes recognized by the World Health Organization. We performed a genomic analysis of 230 PLGGs of which 73 had whole genome/RNA sequencing performed and show that MYB-QKI fusions define the seizure associated tumor, Angiocentric Glioma (AG). MYB-QKI fusions present in AGs contribute to tumorigenesis through three mechanisms: MYB activation by truncation, enhancer translocation driving aberrant MYB-QKI expression, and hemizygous loss of QKI, a tumor suppressor gene. Such interplay between three oncogenic mechanisms has diagnostic and therapeutic implications in AGs, and illustrates the functional complexity associated with rearrangements in cancer. </p>
Project description:Pediatric low-grade gliomas (PLGGs) are among the most common solid tumors in children but apart from BRAF mutations or duplications in specific subclasses, few genetic driver events are known. Diffuse PLGGs comprise a set of uncommon subtypes that exhibit invasive growth and are therefore especially challenging clinically. These tumors are particularly poorly understood. We performed high-resolution copy-number analysis of 44 diffuse PLGGs to identify recurrent alterations. Diffuse PLGGs exhibited fewer such alterations than adult low-grade gliomas, but we identified several significantly recurrent events. The most significant event, 8q13.1 gains, were observed in 28% of diffuse astrocytomas grade II (DA2s) and resulted in partial duplication of the transcription factor MYBL1 with truncation of its C-terminal negative-regulatory domain. A similar recurrent deletion-truncation breakpoint was identified in two angiocentric gliomas in the related gene MYB on 6q23.3. Whole-genome sequencing of a MYBL1-rearranged DA2 demonstrated MYBL1 tandem duplication, and few other events. Two novel, truncated MYBL1 transcripts identified in this tumor induced anchorage-independent growth when expressed in 3T3 cells and tumor formation in nude mice. Truncated transcripts were also expressed in two additional tumors with MYBL1 partial duplication. Our results define clinically relevant molecular subclasses of diffuse PLGGs and highlight a potential role for the MYB family in the biology of low-grade gliomas. IRB approval from all institutions was obtained, and all samples were from patients who provided informed consent or were studied with waiver of the requirement for informed consent by the appropriate IRB. Samples of various histologic subtypes were identified and collected at multiple institutions (Boston Children’s Hospital, Boston, MA, The University of Texas School of Medicine Southwestern, Dallas, TX, Children’s Cancer Hospital, Egypt, Cairo, Johns Hopkins University School of Medicine, Baltimore, MD, Children’s National Medical Center, Washington, DC, The Hospital for Sick Children, Toronto, Canada, Mayo Clinic, Rochester, MN). Central histopathologic review was performed by at least three board-certified neuropathologists using WHO criteria. DNA extraction from archival FFPE samples and Array CGH were performed as previously described (Craig, et al., 2012 PLoS One). GC-normalized copy-number data for the samples were then cleaned of known germline CNVs. Circular Binary Segmentation was used to segment the copy-number data, using parameters [alpha=0.001, undo.splits=sdundo, undo.SD=1.5, min.width=5]. Forty-four samples passed QC metrics (based on aCGH quality metrics for DNA integrity) for inclusion in the GISTIC analysis. Segmented data were analyzed with GISTIC 2.0 to determine statistically significant recurrent broad and focal CNAs. The following parameters were used: minimum segment size = 8, lesion amplitude threshold = 0.2, focal/broad cutoff = 0.9x chromosome arm length, q-value threshold 0.10, and gene confidence level 0.95.
Project description:We carried out the analyses of chromosome variations between low-grade and high-grade gliomas in Chinese population. We found out the differences in chromosomes, cytobands, genes, pathways and GO functions.
Project description:miRNA expression analysis was performed on 14 cases of high grade gliomas and 4 controls obtained from age-matched epileptic patients. After this differentially miRNA analysis has been done among T53,H3F3A,normal and pediatric high grade glioma patient and try to identify the highly altered miRNA expression as well as sno expression pattern.