Skin Cutaneous Melanoma: Correlation between mRNA expression and DNA methylation
(BRAF_Hotspot_Mutants 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 = 99. Number of gene expression samples = 99. Number of methylation samples = 99.

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 = 99

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
cg11578532 TSTD1 1 161008127 -0.89 0 0 5.157 0.667372
cg15518883 SIT1 9 35650561 -0.87 0 0 5.332 0.733183
cg07652628 KRT18 12 53343514 -0.87 0 0 8.637 0.602198
cg11694519 HSPB2 11 111783563 -0.87 0 0 7.216 0.323623
cg02685484 PTPRCAP 11 67203360 -0.87 0 0 7.694 0.784358
cg02836135 SCML4 6 108052093 -0.86 0 0 NA 0.615658
cg14830003 DNALI1 1 38022657 -0.86 0 0 6.213 0.655046
cg07786657 CD247 1 167487633 -0.86 0 0 6.213 0.781143
cg16068833 CD52 1 26644515 -0.86 0 0 7.926 0.702857
cg08075204 BIN2 12 51718112 -0.85 0 0 7.233 0.775277
cg06426416 EVC2 4 5710403 -0.85 0 0 7.169 0.270294
cg05462570 NAALADL1 11 64814948 -0.85 0 0 5.580 0.367494
cg20317872 DENND2D 1 111743202 -0.85 0 0 7.762 0.661550
cg24674703 CD5 11 60869960 -0.84 0 0 6.401 0.754908
cg04489573 TRIM63 1 26394009 -0.84 0 0 NA 0.555335
cg01072786 GLB1L 2 220107847 -0.84 0 0 8.913 0.582451
cg17169196 LTA 6 31540026 -0.83 0 0 NA 0.845001
cg03934354 C1QTNF3 5 34043140 -0.83 0 0 8.603 0.708503
cg00831247 LOXL3 2 74780268 -0.83 0 0 9.767 0.552961
cg15046675 CD37 19 49838777 -0.83 0 0 8.508 0.711157
cg20114113 PPP1R3C 10 93391963 -0.83 0 0 NA 0.649994
cg00903584 PTPN7 1 202128682 -0.83 0 0 7.794 0.649299
cg01232511 PRSS21 16 2867446 -0.83 0 0 NA 0.657010
cg15176213 COX7A1 19 36643572 -0.82 0 0 5.590 0.610217
cg10402417 TBC1D10C 11 67171476 -0.82 0 0 6.503 0.591085
cg11692409 SERPINF1 17 1665181 -0.82 0 0 12.432 0.550102
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-BRAF_Hotspot_Mutants/3155607/0.GDAC_MethylationPreprocess.Finished/SKCM-BRAF_Hotspot_Mutants.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-BRAF_Hotspot_Mutants/3154957/SKCM-BRAF_Hotspot_Mutants.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.