Skin Cutaneous Melanoma: Correlation between mRNA expression and DNA methylation
(WT cohort)
Maintained by Richard Park (Boston University/Harvard Medical School)
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 = 33. Number of gene expression samples = 33. Number of methylation samples = 33.

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 = 33

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
cg05564251 SP140 2 231090640 -0.96 0 0 6.017 0.724420
cg00329300 TSTD1 1 161008462 -0.95 0 0 5.221 0.562017
cg02685484 PTPRCAP 11 67203360 -0.95 0 0 7.654 0.800837
cg10402417 TBC1D10C 11 67171476 -0.94 0 0 6.391 0.604444
cg10673833 MYO1G 7 45018849 -0.94 0 0 7.609 0.741102
cg19585103 SKAP1 17 46507549 -0.94 0 0 5.238 0.569039
cg14359680 GPR132 14 105532208 -0.94 0 0 5.820 0.636459
cg21171625 DNALI1 1 38022607 -0.93 0 0 4.832 0.580679
cg18384097 PTPN7 1 202129566 -0.93 0 0 7.566 0.750143
cg16462073 LAT 16 28995843 -0.93 0 0 7.057 0.798540
cg03665078 TNFAIP8 5 118689961 -0.93 0 0 7.485 0.746645
cg26518580 DENND2D 1 111742515 -0.92 0 0 8.005 0.660401
cg06975979 LRRC61 7 150020025 -0.92 0 0 5.824 0.586530
cg06970090 SPOCK2 10 73848823 -0.92 0 0 9.182 0.561793
cg04881903 CAPG 2 85637116 -0.92 0 0 10.711 0.627658
cg26769927 SPN 16 29674972 -0.92 0 0 7.380 0.761474
cg16068833 CD52 1 26644515 -0.92 0 0 7.844 0.703655
cg08942875 OCIAD2 4 48908902 -0.92 0 0 5.368 0.374458
cg13429423 PARVG 22 44568775 -0.91 0 0 7.622 0.760524
cg08330349 SNX20 16 50715192 -0.91 0 0 5.495 0.598609
cg05462570 NAALADL1 11 64814948 -0.91 0 0 4.919 0.433329
cg25671438 ACAP1 17 7240223 -0.91 0 0 6.613 0.573801
cg01089639 JAK3 19 17959046 -0.91 0 0 8.793 0.534276
cg02298094 SH2B3 12 111844676 -0.91 0 0 10.233 0.323549
cg26842815 PTPN6 12 7060263 -0.91 0 0 8.991 0.565669
cg17127769 LCP2 5 169724590 -0.91 0 0 8.913 0.550838
Methods & Data
Input

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

  • methylation file = /xchip/cga/gdac-prod/tcga-gdac/jobResults/GDAC_MethylationPreprocess/SKCM-WT/3155548/0.GDAC_MethylationPreprocess.Finished/SKCM-WT.meth.for_correlation.filtered_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/SKCM-WT/3155025/SKCM-WT.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

This is an experimental feature. The full results of the analysis summarized in this report can be downloaded from the TCGA Data Coordination Center.