Classification of serrated colorectal tumors
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE4045 | GEO | 2006/07/28
SECONDARY ACCESSION(S): PRJNA95181
REPOSITORIES: GEO
Similar Datasets
Project description:Serrated adenocarcinomas are morphologically different from conventional adenocarcinomas. The serrated pathway has recently been proposed to represent a novel mechanism of colorectal cancer (CRC) formation. However, whether they are biologically different and truly form a distinct subclass of CRC, is not known. This study shows that the gene expression profile of serrated and conventional CRCs differs from each others and that serrated CRCs are not only morphologically novel, but also biologically distinct subclass of CRC. Experiment Overall Design: Total RNA was extracted from fresh frozen tumors with Trizol (GibcoBRL) and purified using RNeasy spin columns (Qiagen). The RNA quality was analyzed using a spectrophotometer and a Agilent 2100 Bioanalyzer (Agilent Technologies). Biotin labeled and fragmented cRNA was prepared from 8 micrograms of total RNA with procedures recommended for the HG-U133 GeneChip expression analysis (Affymetrix). The HG-U133A chips were hybridized, scanned and analyzed with Microarray Suite 5.0 software according to the manufacturerâ??s instructions (Affymetrix).
2007-10-27 | E-GEOD-4045 | biostudies-arrayexpress
Project description:Despite recent different molecular classifications for colorectal cancer (CRC) have been proposed, CRCs are currently diagnosed based their histology [Hamilton] and just a few biomarkers are used to determine the most suitable treatment. It is for this reason important to correlate molecular profiling with histological features. This issue is especially critical in the serrated pathway for colorectal carcinogenesis since it is not as clearly discerned as the conventional adenoma-carcinoma. Furthermore, making the immune surveillance awake against tumor is now considered as a breakthrough in cancer treatment and the serrated pathological pathway comprises two CRC subtypes with typical weak (SAC) and abundant (hMSI-H) immune responses. Therefore, it is crucial to characterize the biology of these tumors since no previous studies have compared their molecular signatures.
2018-06-27 | GSE116305 | GEO
Project description:The serrated adenocarcinoma subtype accounts for 15-30% of all colorectal cancers (CRCs) and is aggressive and treatment-resistant. it is an alternative mechanism for CRC development characterized by dysregulation of the MAPK pathway. We show that human serrated tumors display reduced expression of PKCz and PKCl/i, and that the simultaneous inactivation of these genes in the mouse intestinal epithelium resulted in spontaneous tumorigenesis through the serrated pathway that progressed to advanced cancer. Whereas epithelial PKCl/i deficiency led to immunogenic cell death that repressed tumor initiation, interferon and CD8+ T cell responses were impaired concomitant with stromal activation and immunosuppression driven by PKCz loss. Thus, PKCz and PKCl/i cooperatively suppress serrated tumorigenesis. Targeting this stromal activation and immunosuppression showed synergistic curative activity.
2018-12-20 | GSE109288 | GEO
Project description:The serrated adenocarcinoma subtype accounts for 15-30% of all colorectal cancers (CRCs) and is aggressive and treatment-resistant. it is an alternative mechanism for CRC development characterized by dysregulation of the MAPK pathway. We show that human serrated tumors display reduced expression of PKCz and PKCl/i, and that the simultaneous inactivation of these genes in the mouse intestinal epithelium resulted in spontaneous tumorigenesis through the serrated pathway that progressed to advanced cancer. Whereas epithelial PKCl/i deficiency led to immunogenic cell death that repressed tumor initiation, interferon and CD8+ T cell responses were impaired concomitant with stromal activation and immunosuppression driven by PKCz loss. Thus, PKCz and PKCl/i cooperatively suppress serrated tumorigenesis. Targeting this stromal activation and immunosuppression showed synergistic curative activity.
2018-12-20 | GSE109286 | GEO
Project description:This study was conducted to explore the serum methylome of precancerous lesions belonging to the serrated pathway of colorectal carcinogenesis in a prospective multicentre cohort. Individuals were grouped into five main categories: (i) serrated adenocarcinoma (SAC), (ii) high-risk serrated polyps (HR-SP) comprising traditional serrated adenomas (TSA), sessile serrated lesions (SSL), and serrated polyps (SP) with dysplasia or ≥ 10 mm; (iii) high-risk hyperplastic polyps (HR-HP), defined as HP ≥ 10 mm; (iv) low-risk serrated lesions (LR-SL) including SP without dysplasia < 10 mm and HP < 10 mm; and (v) healthy individuals with no colorectal findings (NCF). First, epigenome-wide methylation levels were quantified in pooled cfDNA samples to characterize the differential methylation profile between no serrated neoplasia (NSN: NCF and LR-SL) and high-risk serrated lesions (HR-SL: HR-HP and HR-SP); concordance with tissue methylation levels was assessed using external datasets. Then, the pathway-specific cfDNA methylation signature was evaluated together with cfDNA pools from the conventional CRC pathway. cfDNA was extracted from serum samples and methylation measurements were assessed with the Infinium MethylationEPIC BeadChip. Data was mainly preprocessed and analyzed with R/Bioconductor packages.
2024-03-01 | GSE199173 | GEO
Project description:Serrated adenocarcinoma (SAC) is a recently recognized colorectal cancer (CRC) subtype accounting for 7.5 - 8.7% of CRCs. It has been shown that SAC has a worse prognosis and has different molecular and immunohistochemical features compared to conventional carcinoma (CC) but, to date, there is no study analysing its methylome profile. We have investigated the methylation status of 450,000 CpG sites using the Infinium Human Methylation 450 BeadChip array in 103 colorectal specimens from Spanish and Finnish patients. The comparison between the epigenetic signature of 36 SACs and 34 matched CCs was established with the aim of identifying the functions which characterize SAC biology and also the most differentially methylated genes for subsequent validatation by pyrosequencing, methylation-specific PCR, qPCR and immunohistochemistry, including additional cases. Microarray data showed a higher representation of morphogenesis-, neurogenesis-, cytoskeleton- and vesicle-transport-related functions and also significant differential methylation of 15 genes, including the iodothyronine deiodinase DIO3 and the forkhead family transcription factor FOXD2 genes which were validated at the CpG, mRNA and protein level. A quantification study of the methylation status of CpG sequences in FOXD2 demonstrated a novel region controlling gene expression. Moreover, differences in these markers were also evident when comparing SAC with CRC showing molecular and histological features of high level microsatellite instability. This methylome study demonstrates that SAC has a distinct epigenetic regulation pattern resulting in different biological functions and that DIO3 and FOXD2 might be molecular targets for a specific histology-oriented treatment of CRC.
2015-06-21 | GSE68060 | GEO
Project description:Serrated adenocarcinoma (SAC) is a recently recognized colorectal cancer (CRC) subtype accounting for 7.5 - 8.7% of CRCs. It has been shown that SAC has a worse prognosis and has different molecular and immunohistochemical features compared to conventional carcinoma (CC) but, to date, there is no study analysing its methylome profile. We have investigated the methylation status of 450,000 CpG sites using the Infinium Human Methylation 450 BeadChip array in 103 colorectal specimens from Spanish and Finnish patients. The comparison between the epigenetic signature of 36 SACs and 34 matched CCs was established with the aim of identifying the functions which characterize SAC biology and also the most differentially methylated genes for subsequent validatation by pyrosequencing, methylation-specific PCR, qPCR and immunohistochemistry, including additional cases. Microarray data showed a higher representation of morphogenesis-, neurogenesis-, cytoskeleton- and vesicle-transport-related functions and also significant differential methylation of 15 genes, including the iodothyronine deiodinase DIO3 and the forkhead family transcription factor FOXD2 genes which were validated at the CpG, mRNA and protein level. A quantification study of the methylation status of CpG sequences in FOXD2 demonstrated a novel region controlling gene expression. Moreover, differences in these markers were also evident when comparing SAC with CRC showing molecular and histological features of high level microsatellite instability. This methylome study demonstrates that SAC has a distinct epigenetic regulation pattern resulting in different biological functions and that DIO3 and FOXD2 might be molecular targets for a specific histology-oriented treatment of CRC. HumanMethylation450K BeadChip (Illumina, Inc, San Diego, CA), using Infinium HD Methylation assay for genome-wide DNA methylation screening, was employed. In brief, genomic DNA (1000 ng) from each sample was bisulfite converted with the EZ DNA Methylation Kit (Zymo Research, Orange, CA) according to the manufacturer´s recommendations. Bisulfite-treated DNA was isothermally amplified at 37°C (20-24h) and the DNA product was fragmented by an endpoint enzymatic process, then precipitated, resuspended, applied to an Infinium Human Methylation450K BeadChip (Illumina, San Diego, CA, USA) and hybridized at 48°C (16-24h). The fluorescently-stained chip was imaged by the Illumina i-SCAN and Illumina's Genome Studio program (Methylation Module) was used to analyze BeadArray data to assign site-specific DNA methylation β-values to each CpG site.
2015-06-21 | E-GEOD-68060 | biostudies-arrayexpress
Project description:Objective: Serrated colorectal cancer (CRC) accounts for approximately 25% of cases, and includes tumours that are amongst the most treatment resistant and with worst outcomes. This CRC subtype is associated with activating mutations in the mitogen activated kinase (MAPK) pathway gene, BRAF, and epigenetic modifications termed the CpG Island Methylator Phenotype (CIMP), leading to epigenetic silencing of key tumour suppressor genes. It is still not clear which (epi-)genetic changes are most important in neoplastic progression and we begin to address this knowledge gap herein. Design: We utilise organoid culture combined with CRISPR/Cas9 genome engineering, to sequentially introduce genetic alterations associated with serrated CRC and which regulate the stem cell niche, senescence and DNA mismatch repair. Results: Targeted biallelic gene alterations were verified by DNA sequencing. Organoid growth in the absence of niche factors was assessed, as well as analysis of downstream molecular pathway activity. Orthotopic engraftment of complex organoid lines, but not BrafV600E alone, quickly generated adenocarcinoma in vivo with serrated features consistent with human disease. Loss of the essential DNA mismatch repair enzyme, Mlh1, led to microsatellite instability. Sphingolipid metabolism genes are differentially regulated in both our mouse models of serrated CRC and human CRC, with key members of this pathway having prognostic significance in the human setting. Conclusion: We generate rapid, complex models of serrated CRC to determine the contribution of specific genetic alterations to carcinogenesis. Analysis of our models alongside patient data has led to the identification of a potential susceptibility for this tumour type.
2018-04-30 | GSE112774 | GEO
Project description:Serrated lesions of the colorectum are the precursors of 15-30% of colorectal cancers (CRCs). These lesions have a peculiar morphological appearance, and they are more difficult to detect than conventional adenomatous polyps. In this study we sought to define the genomic landscape of these lesions using high depth targeted sequencing.
| EGAS00001005648 | EGA
Project description:Our microarray study validates characteristic functions of serrated adenocarcinoma (SAC) reported in the only previous study which was performed on patients from a dissimilar environmental and genetic background and using a different microarray platform. In our study, fascin1 and hippocalcin were validated at the mRNA and protein level as the best biomarkers reported so far for the distinction of SAC from conventional carcinoma and from colorectal carcinoma showing molecular and histological features of high-level microsatellite instability. In this study, we used gene expression arrays to investigate differences between two experimental classes: serrated and conventional carcinomas
2012-10-31 | E-GEOD-36758 | biostudies-arrayexpress