Project description:High-throughput DNA methylation profiling exploits microarray technologies thus providing a wealth of data, which however solicits rigorous, generic and analytical pipelines for an efficient systems level analysis and interpretation. In the present study, we utilize the Illumina's Infinium Human Methylation 450K BeadChip platform in an epidemiological cohort, targeting to associate interesting methylation patterns with breast cancer predisposition. The computational framework proposed here extends the -established in transcriptomic microarrays- logarithmic ratio of the Methylated versus the Unmethylated signal intensities, quoted as M-value. Moreover, intensity-based correction of the M-signal distribution is introduced in order to correct for batch effects and probe-specific errors in intensity measurements. This is accomplished through the estimation of intensity-related error measures from quality control samples included in each chip. Moreover, robust statistical measures based on coefficient variation measurements of DNA methylation between control and case samples alleviate the impact of technical variation. The results presented here are juxtaposed to those derived by applying classical pre-processing and statistical selection methodologies. Overall, in comparison to traditional approaches, the introduced framework's superior performance in terms of technical bias correction, along with its generic character, support its suitability for various microarray technologies. Bisulphite converted DNA from the samples were hybridized to the Illumina Infinium HumanMethylation450 BeadChip
Project description:High-throughput DNA methylation profiling exploits microarray technologies thus providing a wealth of data, which however solicits rigorous, generic and analytical pipelines for an efficient systems level analysis and interpretation. In the present study, we utilize the Illumina's Infinium Human Methylation 450K BeadChip platform in an epidemiological cohort, targeting to associate interesting methylation patterns with breast cancer predisposition. The computational framework proposed here extends the -established in transcriptomic microarrays- logarithmic ratio of the Methylated versus the Unmethylated signal intensities, quoted as M-value. Moreover, intensity-based correction of the M-signal distribution is introduced in order to correct for batch effects and probe-specific errors in intensity measurements. This is accomplished through the estimation of intensity-related error measures from quality control samples included in each chip. Moreover, robust statistical measures based on coefficient variation measurements of DNA methylation between control and case samples alleviate the impact of technical variation. The results presented here are juxtaposed to those derived by applying classical pre-processing and statistical selection methodologies. Overall, in comparison to traditional approaches, the introduced framework's superior performance in terms of technical bias correction, along with its generic character, support its suitability for various microarray technologies.
Project description:Genome wide DNA methylation profiling of human medulloblastoma. The Illumina Infinium 450k Human DNA methylation Beadchip v1.2 was used to obtain DNA methylation profiles across approximately 450,000 CpGs. Preprocessed data performed using Illumina normalization in the minfi package as described in Sturm et al, Cancer Cell, 2012. Bisulphite converted DNA from the 91 samples were hybridised to the Illumina Infinium 450k Human Methylation Beadchip v1.2
Project description:Genome wide DNA methylation profiling of individuals across a large age range. The Illumina Infinium 450k Human DNA methylation Beadchip was used to obtain DNA methylation profiles across approximately 450k CpGs from human whole blood. Bisulphite converted DNA from the 656 samples were hybridised to the Illumina Infinium 450k Human Methylation Beadchip
Project description:Genome wide DNA methylation profiling of individuals across a large age range. The Illumina Infinium 450k Human DNA methylation Beadchip was used to obtain DNA methylation profiles across approximately 450k CpGs from human whole blood.
Project description:Illumina Infinium 450k Human DNA Methylation BeadChip was used to obtain DNA methylation profiles across approximately 450,000 CpGs in 51 central chondrosarcoma. Bisulphite converted DNA from each sample was hybridised to the Illumina Infinium 450k Human Methylation BeadChip.
Project description:Illumina Infinium 450k Human DNA Methylation BeadChip was used to obtain DNA methylation profiles across approximately 450,000 CpGs in Osteosarcoma and Colon Cancer PDXs Bisulphite converted DNA from each sample was hybridised to the Illumina Infinium 450k Human Methylation BeadChip.
Project description:Illumina Infinium 450k Human DNA Methylation BeadChip was used to obtain DNA methylation profiles across approximately 450,000 CpGs in 51 central chondrosarcoma.
Project description:Genome wide DNA methylation profiling of Rett syndrome monozygotic twins. The Illumina Infinium 450k Human DNA methylation Beadchip v1.2 was used to obtain DNA methylation profiles in primary skin fibroblast cells from Rett syndrome monozygotic twins. Bisulphite converted DNA from the 2 samples were hybridised to the Illumina Infinium 450k Human Methylation Beadchip
Project description:We developed a comprehensive analysis pipeline to conduct Epigenome-wide Association Studies (EWAS) using the Illumina Infinium HumanMethylation450 BeadChip, based on data from 2,664 individuals, and 36 samples measured in duplicate. We propose new approaches to quality control, data normalisation and batch correction through control-probe adjustment, and demonstrate that these improve data-quality. Using permutation testing we establish a null hypothesis for EWAS, show how it can be affected by correlation between individual methylation markers and present methods to restore statistical independence. Bisulfite-converted DNA for 2,664 human samples and 36 technical replicates were hybridised to the Illumina Infinium 450k Human Methylation Beadchip v1.2.
