The Epigenomic Landscape of Pituitary Adenomas Reveals Specific Alterations and Differentiates Among Acromegaly, Cushing's Disease and Endocrine-Inactive Subtypes
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE147548 | GEO | 2020/03/26
REPOSITORIES: GEO
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Project description:Colorectal cancer can be divided into four consensus molecular subtypes, which might associate with distinct precursor lesions. The aim of this study was to determine the subtype affiliation of two types of colorectal adenomas: tubular adenomas (TAs) and sessile serrated adenomas (SSAs) and to determine the activity of TGFβ signaling and the role of this cytokine in subtype affiliation. Adenoma samples were collected in the Academic Medical Center (AMC), Amsterdam, The Netherlands. Tubular adenomas (TAs) were obtained from familial adenomatous polyposis (FAP) patients and sessile serrated adenomas (SSAs) were collected from serrated polyposis syndrome (SPS) patients.
2016-06-01 | GSE79460 | GEO
Project description:Aberrant methylation of DNA is supposed to be a major and early driver of colonic adenoma development and may also lead to colorectal cancer (CRC) formation. While gene methylation assays are used already for CRC screening, differential epigenetic alterations of recurring and non-recurring colorectal adenomas have yet not been systematically investigated. Here, we collected a sample set (n=72) of formalin-fixed paraffin-embedded (FFPE) primary colorectal adenomas without recurrence (n=30), primary adenomas with recurrence at the same location (n=19), so-called “matched pair samples” (n=10; comprising the primary adenoma and the recurrent adenoma) and normal mucosa specimens (n=3). We aimed to unveil differentially methylated CpG positions (DMPs) across the methylome of the selected samples using the Illumina HumanMethylation 450K BeadChip array. Unsupervised hierarchical clustering exhibited a significant association of methylation patterns with the histological subtypes. No significant DMPs were identified comparing primary adenomas with and without recurrence. Despite that, a total of 5,094 DMPs (FDR<0.05, fold change>10%) were identified in the comparisons of recurrent adenomas vs. (non-) matched primary adenomas with recurrence (674; 98% hypermethylated), recurrent adenomas vs. primary adenomas with and without recurrence (241; 99% hypermethylated) and adenomas vs. normal mucosae (4,179; 46% hypermethylated). DMPs in CpG islands were frequently hypermethylated whereas open sea and shelves exhibited hypomethylation. Gene ontological analysis demonstrated enrichment of genes associated with the immune system, inflammatory processes, and cancer-pathways. We conclude that methylation data is helpful to contribute to a more stable and reproducible histological adenoma classification which is a prerequisite to establishing profound surveillance guidelines
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Project description:Genetic and epigenetic alterations are a fundamental aspect of colorectal cancer formation. There is considerable heterogeneity between colorectal cancers regarding the mutations and methylated genes they carry, and this heterogeneity may arise early in the polyp-cancer sequence. However, our understanding of the epigenetic alterations and gene mutations in colon adenomas and their relation to colorectal cancer is incomplete. Thus, we have assessed the methylome in normal colon mucosa, tubular adenomas, and colorectal adenocarcinomas and have determined the relationship of these findings between adenomas and cancer in the colon. Genome-wide alterations in DNA methylation were found in the normal colon mucosa adjacent to colorectal cancer, tubular adenomas, and colorectal cancer. Three subgroups of CRCs and two subgroups of adenomas were identified on the basis of their DNA methylation patterns. The adenomas separated into a high-frequency methylation class (Adenoma-H) and a low-frequency methylation class. The adenoma-H polyps have a methylated DNA signature similar to non-CIMP CRCs, whereas those of the Adenoma-L class have a similar methylation pattern to normal colon mucosa. The CpGs that account for these signatures are located in intragenic/intergenic regions, which suggests that these two groups of adenomas arise from different stem cell populations. We conducted genome-wide array-based studies and comprehensive data analyses of aberrantly methylated loci in 41 normal colon samples, 42 colon adenomas, and 64 colorectal cancers. Supplementary file 'GSE48684_Matrix_signal_intensities_1.txt.gz': includes the unmethylated and methylated signal intensities from Samples GSM1183439-GSM1183561. Supplementary file 'GSE48684_Matrix_signal_intensities_2.txt.gz': includes the unmethylated and methylated signal intensities from Samples GSM1235135-GSM1235158.
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Project description:Corticotropin (ACTH)-secreting pituitary adenomas give rise to a severe endocrinological disorder, i.e., Cushing’s disease, with multifaceted clinical presentation and treatment outcomes. Experimental studies suggested that disease variability is inherent to the pituitary tumor, thus pointing to the need for further studies into tumor biology. Aim of the present study was to evaluate transcriptome expression pattern in a large series of ACTH-secreting pituitary adenoma specimens, in order to identify molecular signatures of these tumors. Gene expression profiling of formalin-fixed paraffin-embedded specimens from 40 human ACTH-secreting pituitary adenomas revealed significant expression of genes involved in protein biosynthesis and ribosomal function, in keeping with neuroendocrine cell profile. Unsupervised cluster analysis identified three distinct gene profile clusters and several genes were uniquely overexpressed in a given cluster, accounting for different molecular signatures. Of note, gene expression profiles were associated with clinical features such as age and size of the tumor. Altogether, our study shows that corticotrope tumors are characterized by neuroendocrine gene expression profile and present subgroup-specific molecular features.
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Project description:This series includes the four major subtypes of pituitary adenomas and normal post-mortem pituitary tissue; Data Transformation; Using Affymetrix Microarray Suite 5.0 global scaling was applied to the quantification data to adjust the average recorded to a target intensity of 100. Data were then exported into the bioinformatics software GeneSpring 6.0 (Silicon Genetics, Redwood City, CA) for further analysis. Data normalization was performed to scale the data so that the average intensity value on each array was 1 by dividing each expression value by the median of the expression levels on each chip. The individual gene expression levels for each of the 4 pituitary adenoma subtype arrays was divided by the expression level in the normal pituitary array. Thus, the data are presented as relative to the expression in normal pituitary tissue. Filtering was then performed to identify genes over-expressed or under-expressed at least 2.0 fold in tumours compared to normal pituitary. TABLE 1:; The genes / ESTs differentially overexpressed >= 2-fold in at least one pituitary adenoma subtype compared to normal pituitary. Negative values represent underexpression. Where genes are represented by more than one probe set, individual probe data sets are given. TABLE 2:; The genes / ESTs differentially underexpressed >= 2-fold in at least one pituitary adenoma subtype compared to normal pituitary. Negative values represent underexpression. Where genes are represented by more than one probe set, individual probe data sets are given.
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