DNA methylation analyses of urothelial carcinoma reveal distinct epigenetic subtypes and an association between gene copy number and methylation status
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE33510 | GEO | 2012/08/31
SECONDARY ACCESSION(S): PRJNA148825
REPOSITORIES: GEO
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Project description:We assessed DNA methylation and copy number status of 27,000 CpGs in 149 urothelial carcinomas and integrated the findings with gene expression and mutation data. Methylation was associated with gene expression for 1,332 CpGs, of which 26% showed positive correlation with expression, i.e., high methylation and high gene expression levels. These positively correlated CpGs were part of specific transcription factor binding sites, such as sites for MYC and CREBP1, or located in gene bodies. Furthermore, we found genes with copy number gains, low expression and high methylation levels, revealing an association between methylation and copy number levels. This phenomenon was typically observed for developmental genes, such as HOX genes and tumor suppressor genes. In contrast, we also identified genes with copy number gains, high expression and low methylation levels. This was for instance observed for some keratin genes. Tumor cases could be grouped into four subgroups, termed epitypes, by their DNA methylation profiles. One epitype was influenced by the presence of infiltrating immune cells, two epitypes were mainly composed of non-muscle invasive tumors, and the remaining epitype of muscle invasive tumors. The polycomb complex protein EZH2 that blocks differentiation in embryonic stem cells showed increased expression both at the mRNA and protein levels in the muscle invasive epitype, together with methylation of polycomb target genes and HOX genes. Our data highlights HOX gene silencing and EZH2 expression as mechanisms to promote a more undifferentiated and aggressive state in UC. The study was conducted on genomic DNA from 150 primary fresh-frozen urothelial carcinoma tumors selected to have equal representation of stages Ta, T1 and T2>. The design also included four fully methylated and four unmethylated hybridization controls as well as 7 Normal urothelium samples. One tumor sample (UC_0556_1) was included as a technical replicate in each of four bisulfite treatment batches. The samples were bisulfite treated and hybridized to Illumina Human Methylation27 Bead Chip arrays according to manufacturers instructions at the SCIBLU Genomics Centre at Lund University, Sweden. Note: Illumina methylation data set comprises total of 168 samples (raw data), but 156 samples (processed data), derived from primary urothelial carcinoma samples. See README.txt for details of the 12 samples not included in the final, processed data.
2012-08-31 | E-GEOD-33510 | biostudies-arrayexpress
Project description:Aberrant DNA methylation is frequently observed in breast cancer. However, the relationship between methylation patterns and the heterogeneity of breast cancer has not been comprehensively characterized. Whole-genome DNA methylation analysis using 450K Illumina BeadArrays was performed on 188 human breast tumors. Unsupervised bootstrap consensus clustering was performed to identify DNA methylation epigenetic subgroups (epitypes). The Cancer Genome Atlas data, incluing methylation profiles of 669 human breast tumors, was utilized for validation. The identified epitypes were characterized by integration with publicly available genome-wide data, including gene expression levels, DNA copy numbers, whole-exome sequencing data, and chromatin states. We identified seven breast cancer epitypes. One epitype was distinctly associated with basal-like tumors and with BRCA1 mutations, one epitype contained a subset of ERBB2-amplified tumors characterized by multiple additional amplifications and the most complex genomes, and one epitype displayed a methylation profile similar to normal epithelial cells. Luminal tumors were stratified into the remaining four epitypes, with differences in promoter hypermethylation, global hypomethylation, proliferative rates and genomic instability. We observed two dominant patterns of aberrant methylation in breast cancer. One pattern, constitutively methylated in both basal-like and luminal breast cancer, was linked to genes with promoters in a Polycomb-repressed state in normal epithelial cells and displayed no correlation to gene expression levels. The second pattern correlated with gene expression levels and was associated with methylation in luminal tumors and genes with active promoters in normal epithelial cells. Our results suggest that hypermethylation patterns in basal-like breast cancer may have limited influence on tumor progression and instead reflects the repressed chromatin state of the tissue of origin. On the contrary, hypermethylation patterns specific to luminal breast cancer influence gene expression, may contribute to tumor progression, and may present an actionable epigenetic alteration in some luminal breast cancers. Genome-wide DNA methylation analysis of 188 breast cancers using Illumina Human Methylation 450K Beadchips.
2016-02-29 | E-GEOD-75067 | biostudies-arrayexpress
Project description:Aberrant DNA methylation is frequently observed in breast cancer. However, the relationship between methylation patterns and the heterogeneity of breast cancer has not been comprehensively characterized. Whole-genome DNA methylation analysis using 450K Illumina BeadArrays was performed on 188 human breast tumors. Unsupervised bootstrap consensus clustering was performed to identify DNA methylation epigenetic subgroups (epitypes). The Cancer Genome Atlas data, incluing methylation profiles of 669 human breast tumors, was utilized for validation. The identified epitypes were characterized by integration with publicly available genome-wide data, including gene expression levels, DNA copy numbers, whole-exome sequencing data, and chromatin states. We identified seven breast cancer epitypes. One epitype was distinctly associated with basal-like tumors and with BRCA1 mutations, one epitype contained a subset of ERBB2-amplified tumors characterized by multiple additional amplifications and the most complex genomes, and one epitype displayed a methylation profile similar to normal epithelial cells. Luminal tumors were stratified into the remaining four epitypes, with differences in promoter hypermethylation, global hypomethylation, proliferative rates and genomic instability. We observed two dominant patterns of aberrant methylation in breast cancer. One pattern, constitutively methylated in both basal-like and luminal breast cancer, was linked to genes with promoters in a Polycomb-repressed state in normal epithelial cells and displayed no correlation to gene expression levels. The second pattern correlated with gene expression levels and was associated with methylation in luminal tumors and genes with active promoters in normal epithelial cells. Our results suggest that hypermethylation patterns in basal-like breast cancer may have limited influence on tumor progression and instead reflects the repressed chromatin state of the tissue of origin. On the contrary, hypermethylation patterns specific to luminal breast cancer influence gene expression, may contribute to tumor progression, and may present an actionable epigenetic alteration in some luminal breast cancers.
2016-02-29 | GSE75067 | GEO
Project description:Lung cancer is the worldwide leading cause of death from cancer. DNA methylation in gene promoter regions is a major mechanism of gene expression regulation that may promote tumorigenesis. However, whether clinically relevant subgroups based on DNA methylation patterns exist in lung cancer is not well studied. We performed whole-genome methylation analysis using 450K Illumina BeadArrays on 124 tumors including 83 adenocarcinomas, 23 squamous cell carcinomas, one adenosquamous cancer, five large cell carcinomas, nine large cell neuroendocrine carcinomas (LCNEC), three small cell carcinomas (SCLC) and 12 normal lung tissues. Unsupervised class discovery was performed to identify DNA methylation subgroups with clinicopathological and molecular features. Subgroups were validated in two independent NSCLC cohorts. Unsupervised analysis identified five DNA methylation subgroups (epitypes). One epitype was distinctly associated with neuroendocrine tumors (LCNEC and SCLC). For adenocarcinoma, in both discovery and validation cohorts, remaining four epitypes were associated with differences in clinicopathological and molecular features, including global hypomethylation, promoter hypermethylation, copy number alterations, expression of proliferation-associated genes, association with unsupervised and supervised gene expression phenotypes, KRAS, TP53, KEAP1, SMARCA4, and STK11 mutations, smoking history, and patient outcome. Based on a multicohort approach we conducted a comprehensive survey of genome-wide DNA methylation in lung cancer, identifying a distinct neuroendocrine epitype and four adenocarcinoma epitypes associated with molecular and clinicopathological characteristics, and patient outcome. Our results bring further understanding of the epigenetic characteristics and molecular diversity in lung cancer generally and in adenocarcinoma specifically. Genome-wide DNA methylation analysis of 124 lung carcinomas and 12 normal lung tissues using Illumina Human Methylation 450K v1.0 Beadchips.
2014-10-05 | E-GEOD-56044 | biostudies-arrayexpress
Project description:Lung cancer is the worldwide leading cause of death from cancer. DNA methylation in gene promoter regions is a major mechanism of gene expression regulation that may promote tumorigenesis. However, whether clinically relevant subgroups based on DNA methylation patterns exist in lung cancer is not well studied. We performed whole-genome methylation analysis using 450K Illumina BeadArrays on 124 tumors including 83 adenocarcinomas, 23 squamous cell carcinomas, one adenosquamous cancer, five large cell carcinomas, nine large cell neuroendocrine carcinomas (LCNEC), three small cell carcinomas (SCLC) and 12 normal lung tissues. Unsupervised class discovery was performed to identify DNA methylation subgroups with clinicopathological and molecular features. Subgroups were validated in two independent NSCLC cohorts. Unsupervised analysis identified five DNA methylation subgroups (epitypes). One epitype was distinctly associated with neuroendocrine tumors (LCNEC and SCLC). For adenocarcinoma, in both discovery and validation cohorts, remaining four epitypes were associated with differences in clinicopathological and molecular features, including global hypomethylation, promoter hypermethylation, copy number alterations, expression of proliferation-associated genes, association with unsupervised and supervised gene expression phenotypes, KRAS, TP53, KEAP1, SMARCA4, and STK11 mutations, smoking history, and patient outcome. Based on a multicohort approach we conducted a comprehensive survey of genome-wide DNA methylation in lung cancer, identifying a distinct neuroendocrine epitype and four adenocarcinoma epitypes associated with molecular and clinicopathological characteristics, and patient outcome. Our results bring further understanding of the epigenetic characteristics and molecular diversity in lung cancer generally and in adenocarcinoma specifically.
2014-10-05 | GSE56044 | GEO
Project description:Acute myeloid leukemia (AML) is a molecularly complex disease characterized by heterogeneous tumor genetic profiles and involving numerous pathogenic mechanisms and pathways. Integration of molecular data types across multiple patient cohorts may advance current genetic approaches for improved sub-classification and understanding of the biology of the disease. Here we analyzed genome-wide DNA methylation in 649 AML patients using Illumina arrays and identified a configuration of 13 subtypes (termed ‘epitypes’) using unbiased clustering. Integration of genetic data revealed that most epitypes were associated with a certain recurrent mutation (or combination) in a majority of patients, yet other epitypes were largely independent. Epitypes demonstrated developmental blockage at discrete stages of myeloid differentiation, revealing epitypes that retain arrested hematopoietic stem cell-like phenotypes. Detailed analyses of DNA methylation patterns identified unique patterns of aberrant hyper- and hypomethylation among epitypes, with variable involvement of transcription factors influencing promoter, enhancer and repressed regions. Patients in epitypes with stem cell-like methylation features showed inferior overall survival along with upregulated stem cell gene expression signatures. We further identified a DNA methylation signature involving STAT motifs associated with FLT3-ITD mutations. Finally, DNA methylation signatures were remarkably stable at relapse for the large majority of patients, and rare epitype switching accompanied loss of the dominant epitype mutations and reversion to stem cell-like methylation patterns. These results demonstrate that DNA methylation-based classification integrates important molecular features of AML to reveal the diverse pathogenic and biological aspects of the disease.
2021-03-09 | GSE159907 | GEO
Project description:Main goal of the study is to distinguish stable DNA methylation differences from dynamic changes during the annual cycle in different epitypes. We examined whether the extant epigenetic marks created during embryogenesis under EpI-temperature conditions are maintained in the resulting epitype trees. We used unique well-defined clonal epitypes with a stable epigenetic memory of the temperature sum experienced during embryogenesis impacting bud phenology. Due to the massive size of the Norway spruce genome (Nystedt et al., 2013), we used a targeted approach to address the DNA methylation status at a single-base resolution in specific target gene regions of selected genes involved in the epigenetic machinery and adaptive traits formation. From these we have characterized DNA methylation patterns in apical buds for 10 time points throughout the year to observe the differences between epitypes and its dynamics through the annual cycle of development.
2023-08-01 | GSE222491 | GEO
Project description:Purpose: DNA methylation alterations are early events in tumorigenesis and important in the regulation of gene expression in cancer cells. Lung cancer has in general a poor prognosis, and a deeper insight into the epigenetic landscape in lung adenocarcinoma tumors and its prognostic implications is needed. Experimental Design: We determined whole-genome DNA methylation profiles of 164 lung adenocarcinoma samples and 19 samples of matched normal lung tissue samples using the Illumina Infinium 450K array [GSE66836]. The methylation levels were correlated with gene expression levels analyzed by the Agilent 60K mRNA expression array. Methylation changes were studied specifically in tumors from never-smoking patients, and in tumors with mutations in the EGFR-, KRAS- or TP53 genes, and survival analyses were performed. Results: We identified a large number of differentially methylated CpGs in lung adenocarcinoma tissue, and different methylation profiles in tumors from smokers and never-smokers. Specific methylation profiles were observed in tumors with mutations in the EGFR-, KRAS- or TP53 gene. Both positive and negeative correlations between DNA methylation levels and mRNA expression levels were seen. Methylation profiles of the tumor samples identified clusters of patients with distinct prognosis. A prognostic index based on the methylation levels of 33 CpGs was established, and validated in an independent cohort of lung adenocarcinoma patients from the TCGA project. Among the CpGs in the prognostic signature, some were localized in the HOX B and HOX C gene clusters. Conclusions: Methylation differences mirror biological important features the etiology of lung adenocarcinomas and influence prognosis.
2015-11-13 | GSE66863 | GEO
Project description:Purpose: DNA methylation alterations are early events in tumorigenesis and important in the regulation of gene expression in cancer cells. Lung cancer has in general a poor prognosis, and a deeper insight into the epigenetic landscape in lung adenocarcinoma tumors and its prognostic implications is needed. Experimental Design: We determined whole-genome DNA methylation profiles of 164 lung adenocarcinoma samples and 19 samples of matched normal lung tissue samples using the Illumina Infinium 450K array. The methylation levels were correlated with gene expression levels analyzed by the Agilent 60K mRNA expression array. Methylation changes were studied specifically in tumors from never-smoking patients, and in tumors with mutations in the EGFR-, KRAS- or TP53 genes, and survival analyses were performed. Results: We identified a large number of differentially methylated CpGs in lung adenocarcinoma tissue, and different methylation profiles in tumors from smokers and never-smokers. Specific methylation profiles were observed in tumors with mutations in the EGFR-, KRAS- or TP53 gene. Both positive and negeative correlations between DNA methylation levels and mRNA expression levels were seen. Methylation profiles of the tumor samples identified clusters of patients with distinct prognosis. A prognostic index based on the methylation levels of 33 CpGs was established, and validated in an independent cohort of lung adenocarcinoma patients from the TCGA project. Among the CpGs in the prognostic signature, some were localized in the HOX B and HOX C gene clusters. Conclusions: Methylation differences mirror biological important features the etiology of lung adenocarcinomas and influence prognosis.
2015-11-27 | GSE66836 | GEO
Project description:We profiled DNA copy numbers, DNA methylation, and mRNA expression levels in the same HCC patients. To identify genes which transcriptional expression levels are regulated by genomic and/or epigenetic deregulation, we defined the copy number-correlated and methylation-correlated genes with their corresponding gene expression levels across the samples as genic and epigenetic deregulators, respectively.
2017-10-05 | GSE87630 | GEO