Correlation between mRNA expression and DNA methylation
Testicular Germ Cell Tumors (Primary solid tumor)
28 January 2016  |  analyses__2016_01_28
Maintainer Information
Citation Information
Maintained by Richard Park (Boston University/Harvard Medical School)
Cite as Broad Institute TCGA Genome Data Analysis Center (2016): Correlation between mRNA expression and DNA methylation. Broad Institute of MIT and Harvard. doi:10.7908/C1JH3KNW
Overview
Introduction

The role of general epigenetic mechanisms in carcinogenesis and tumor aggressiveness is well documented: CpG island hyper-methylation silences tumor suppressor genes, whereas hypo-methylation promotes the transcriptional activation of oncogenes and induces chromosomal instability. This pipeline calculates and identifies correlations between DNA methylation and gene expression profiles using the available array technologies.

Summary

The top 25 correlated methylation probes per gene are displayed. Total number of matched samples = 150. Number of gene expression samples = 150. Number of methylation samples = 150.

Results
Correlation Histogram

Figure 1.  Histogram of methylation correlation values. n is the number of matched samples between Level 3 CpG site methylation and Level 3 gene expression arrays. Number of Matched Samples = 150

Qvalue Summary Plots

Figure 2.  Plot 1. The estimated pi_0 versus the tuning parameter lambda. Plot 2. The q-values versus the p-values. Plot 3. The number of significant tests versus each q-value cutoff. Plot 4. The number of expected false positives versus the number of significant tests.The first is a plot of the estimate of pi_0 versus its tuning parameter lambda. In most cases, as lambda gets larger, the bias of the estimate decreases, yet the variance increases. Comparing your estimate of pi_0 to this plot allows one to guage its quality. The remaining three plots show how many tests are significant, as well as how many false positives to expect for each q-value cut-off.

Negative Correlation between Methylation and Gene Expression

Table 1.  Get Full Table Top 25 most negatively correlated methylation probes. Correlation Coefficient: See Methods & Data below. Pval and Qval: P- and Q-values of the correlation coefficient. Expression Mean: mean detection level of gene expression probes. Methylation Mean: mean detection level of CpG methylation probes.

Meth_Probe Gene Chrom Position Corr_Coeff Pval Qval Expr_Mean Meth_Mean
cg02310286 DCAF4L2 8 88886432 -0.9 0 0 7.4 0.57
cg14855529 RNF17 13 25338146 -0.9 0 0 6.3 0.57
cg10378927 ZNF766 19 52777016 -0.9 0 0 9.6 0.63
cg10215766 GATAD2A 19 19612808 -0.89 0 0 12 0.77
cg27457191 PHTF2 7 77429766 -0.89 0 0 11 0.42
cg02899723 DDX4 5 55033614 -0.89 0 0 5.6 0.64
cg01794862 SLC4A8 12 51822406 -0.88 0 0 10 0.65
cg20489239 SOCS4 14 55514980 -0.87 0 0 11 0.72
cg00815117 C17orf63 17 27085788 -0.87 0 0 11 0.8
cg03758367 GTSF1 12 54867542 -0.87 0 0 8.6 0.52
cg03168501 TDRD12 19 33211891 -0.87 0 0 7.4 0.73
cg25397029 ANKRD2 10 99338240 -0.87 0 0 5.1 0.5
cg17048169 NGEF 2 233744073 -0.87 0 0 10 0.63
cg19804859 PRAME 22 22901145 -0.87 0 0 8.7 0.52
cg14561276 MLL4 19 36210811 -0.86 0 0 11 0.63
cg02937873 WDR62 19 36595986 -0.86 0 0 10 0.61
cg06900650 TUBA3E 2 130956219 -0.86 0 0 4.3 0.77
cg09656738 BTBD18 11 57520552 -0.86 0 0 3.1 0.67
cg15461748 GCAT 22 38212788 -0.86 0 0 8.8 0.63
cg15522939 ZNF490 19 12688727 -0.86 0 0 9.8 0.65
cg00967637 C2orf65 2 74875932 -0.86 0 0 6.6 0.73
cg22867538 BRAP 12 112121020 -0.86 0 0 10 0.76
cg25828381 TUBA3D 2 132233769 -0.86 0 0 5.7 0.77
cg14919260 ZNF607 19 38206160 -0.86 0 0 9.1 0.69
cg24045861 HKR1 19 37827884 -0.86 0 0 11 0.69
cg07278705 TEC 4 48269743 -0.86 0 0 7.4 0.67
Methods & Data
Input

Methylation Array Platforms: Illumina Infinium HumanMethylation27, Illumina Infinium HumanMethylation450, Illumina DNA Methylation OMA002, Illumina DNA Methylation OMA003

  • methylation file = /xchip/cga/gdac-prod/tcga-gdac/jobResults/GDAC_MethylationPreprocess/TGCT-TP/22316724/TGCT-TP.meth.by_min_expr_corr.data.txt

Gene Expression Platforms: Agilent 244K Gene Expression G4502A-07-1, Agilent 244K Gene Expression G4502A-07-2, Agilent 244K Gene Expression G4502A-07-3, Affymetrix Human Exon 1.0 ST Array, Affymetrix HT Human Genome U133 Array

  • gene expression file = /xchip/cga/gdac-prod/tcga-gdac/jobResults/mRNAseq_preprocessor/TGCT-TP/22312654/TGCT-TP.uncv2.mRNAseq_RSEM_normalized_log2.txt

Correlation Coefficient

Level 3 methylation and gene expression arrays were paired on the basis of Entrez Gene ID concordance. The association between CpG site methylation and the level of expression of the corresponding genes was determined by calculating a correlation measure between the two platforms.

  • correlation measure = Spearman

Download Results

In addition to the links below, the full results of the analysis summarized in this report can also be downloaded programmatically using firehose_get, or interactively from either the Broad GDAC website or TCGA Data Coordination Center Portal.