Skin Cutaneous Melanoma: Correlation between mRNA expression and DNA methylation
(All_Primary 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 = 43. Number of gene expression samples = 43. Number of methylation samples = 43.

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 = 43

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
cg00032205 TSPYL5 8 98290372 -0.92 0 0 7.3436 0.528022
cg20485758 HFE 6 26088446 -0.9 0 0 6.0553 0.521196
cg19083407 PAX8 2 113993142 -0.89 0 0 4.2873 0.705382
cg06975979 LRRC61 7 150020025 -0.89 0 0 5.7361 0.659850
cg04881903 CAPG 2 85637116 -0.88 0 0 11.4404 0.565946
cg20317872 DENND2D 1 111743202 -0.88 0 0 7.1823 0.720696
cg13515269 BHLHE41 12 26274368 -0.87 0 0 10.1880 0.604969
cg05671385 CARD16 11 104915759 -0.87 0 0 7.2290 0.445662
cg12044599 PTPRCAP 11 67206308 -0.87 0 0 6.5922 0.869466
cg01733570 DFNA5 7 24797656 -0.87 0 0 8.4923 0.559164
cg08551725 SCRN1 7 30029776 -0.87 0 0 9.7548 0.491995
cg26841048 HOXB2 17 46622454 -0.86 0 0 6.5578 0.554168
cg03540028 RIPK4 21 43183977 -0.86 0 0 8.9506 0.720903
cg07652628 KRT18 12 53343514 -0.86 0 0 7.1531 0.705786
cg11692409 SERPINF1 17 1665181 -0.86 0 0 12.5624 0.549707
cg14830003 DNALI1 1 38022657 -0.86 0 0 4.5723 0.712477
cg21342728 MCHR1 22 41075673 -0.85 0 0 5.1267 0.570112
cg18653451 CCDC8 19 46917018 -0.85 0 0 7.6733 0.384043
cg11882252 CMBL 5 10307634 -0.85 0 0 6.8080 0.240571
cg17127769 LCP2 5 169724590 -0.85 0 0 8.3742 0.562486
cg16363586 BST2 19 17516329 -0.84 0 0 10.7156 0.518231
cg00831247 LOXL3 2 74780268 -0.84 0 0 8.5787 0.664527
cg19708901 KIAA1614 1 180882655 -0.84 0 0 7.0259 0.367505
cg10091866 HMCN1 1 185704549 -0.84 0 0 11.9134 0.296291
cg21304163 FXYD3 19 35607221 -0.84 0 0 9.6497 0.644324
cg18515587 SELENBP1 1 151344806 -0.84 0 0 9.3703 0.531163
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-All_Primary/3155628/0.GDAC_MethylationPreprocess.Finished/SKCM-All_Primary.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-All_Primary/3154834/SKCM-All_Primary.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.