Project description:Comprehensive DNA methylation analysis in malignant melanoma clinical samples and primary melanocyte culture. Infinium MethylationEPIC BeadChip was used to obtain DNA methylation profiles. Samples included 8 malignant melanoma cases and primary melanocyte culture.
Project description:Comprehensive DNA methylation analysis in malignant melanoma clinical samples. Infinium HumanMethylation450 BeadChip was used to obtain DNA methylation profiles across 485,577 CpG sites. Samples included 54 malignant melanoma cases and primary melanocyte culture.
Project description:Malignant melanoma is a highly metastatic disease disseminating to several distant sites. This potential is also of great clinical impact for patient survival and therapeutic success. Knowledge about melanoma genomics is mainly based on lymphatic or skin metastases derived data, whereas data from distant sites is rather limited. Therefore, an autopsy-based visceral metastasis biobank was established and an array-based CNV analysis was performed focusing primarily on major organs (brain, lung and liver) on a total of 38 samples (10 primary and 28 organ metastasse). A unique picture emerged about organ specific CNV type distributions or gene alterations including the frequent loss of DNA damage error genes in brain metastases, the presence of HGF/MET autocrine loop in brain and lung metastases, the traces of immunogenic mimicry exclusive for lung metastases or the correlation of BRAF copy number and mutant allele frequency especially in lung metastases. All these above phenomena have a great influence on therapy efficacy or resistance.
Project description:Genome-wide DNA methylation profiling using the Illumina EPIC 850k DNA methylation BeadChip array on 8 pools of human genomic DNA from whole blood for 190 individuals age matched at 4 time points; ~4, ~28, ~63, & ~78 years.
Project description:Background: Epigenome-wide association studies (EWAS) have been widely applied to identify methylation CpG sites associated with human disease. To date, the Infinium Methylation EPIC array (EPIC) is commonly used for high-throughput DNA methylation profiling. However, the EPIC array covers only 30% of the human methylome. Methylation Capture bisulfite sequencing (MC-seq) captures target regions of methylome and has advantages of extensive coverage in the methylome at an affordable price. Methods: Epigenome-wide DNA methylation in four peripheral blood mononuclear cell samples was profiled by using SureSelectXT Methyl-Seq for MC-seq and EPIC platforms separately. CpG site-based reproducibility of MC-seq was assessed with DNA sample inputs ranging in quantity of high (> 1000ng), medium (300-1000ng), and low (150ng-300ng). To compare the performance of MC-seq and the EPIC arrays, we conducted a Pearson correlation and methylation value difference at each CpG site that was detected by both MC-seq and EPIC. We compared the percentage and counts in each CpG island and gene annotation between MC-seq and the EPIC array. Results: After quality control, an average of 3,708,550 CpG sites per sample was detected by MC-seq with DNA quantity >1000ng. Reproducibility of MC-seq detected CpG sites was high with strong correlation estimates for CpG methylation among samples with high, medium, and low DNA inputs (r > 0.96). The EPIC array captured an average of 846,464 CpG sites per sample. Compared with the EPIC array, MC-seq detected more CpGs in coding regions and CpG islands. Among the 472,540 CpG sites captured by both platforms, methylation of a majority of CpG sites was highly correlated in the same sample (r: 0.98~0.99). However, methylation for a small proportion of CpGs (N=235) differed significantly between the two platforms, with differences in beta values of greater than 0.5. Conclusions: Our results show that MC-seq is an efficient and reliable platform for methylome profiling with a broader coverage of the methylome than the array-based platform. Although methylation measurements in majority of CpGs are highly correlated, a number of CpG sites show large discrepancy between the two platforms, which warrants further investigation and needs cautious interpretation.
Project description:Illumina Infinium HumanMethylation850 BeadChip (also known as Illumina EPIC array, GPL23976) was used to generate DNA methylation data from synthetic DNA from 3 species. The DNA samples from each species were enzymatically manipulated so that they would exhibit 0%, 25%, 50%, 75% and 100% percent methylation at each CpG location, respectively. The variable “ProportionMethylated” (with ordinal values 0, 0.25, 0.5, 0.75, 1) can be interpreted as a benchmark for each CpG that maps to the respective genome. Thus, the DNA methylation levels of each CpG are expected to have a high positive correlation with ProportionMethylated across the arrays measurement for the human species. The human EPIC array was applied to calibration data from mouse (n=15 EPIC arrays, 3 per methylation level) and rat (n=10, 2 per methylation level). The EPIC array data were normalized using the noob method (R function preprocessNoob in minfi).