Skin Cutaneous Melanoma: Correlation between mRNA expression and DNA methylation
(NF1_Any_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 = 31. Number of gene expression samples = 31. Number of methylation samples = 31.

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 = 31

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
cg15518883 SIT1 9 35650561 -0.96 0 0 5.1057 0.779767
cg12436568 PTPN7 1 202130728 -0.96 0 0 7.1625 0.669047
cg11578532 TSTD1 1 161008127 -0.95 0 0 4.8753 0.703176
cg04881903 CAPG 2 85637116 -0.94 0 0 11.0717 0.611374
cg24080793 ICAM2 17 62097951 -0.93 5.7e-09 2.7e-06 6.9705 0.760743
cg12947833 HSPB2 11 111783499 -0.93 1.4e-08 5.6e-06 7.0618 0.317451
cg09302355 FERMT3 11 63974131 -0.92 4.8e-08 0.000013 9.4607 0.497836
cg20792833 PTPRCAP 11 67205195 -0.92 5.4e-08 0.000013 7.2268 0.711274
cg00027570 CD2 1 117306669 -0.91 6.6e-08 0.000013 7.1847 0.835922
cg14110548 HCST 19 36393696 -0.91 7.9e-08 0.000013 6.8540 0.748476
cg08422803 ITGB2 21 46341067 -0.91 8.3e-08 0.000013 10.4781 0.777422
cg25671438 ACAP1 17 7240223 -0.91 8.3e-08 0.000013 6.4465 0.611895
cg19885625 NAALADL1 11 64815313 -0.91 8.7e-08 0.000013 5.2375 0.420513
cg01072786 GLB1L 2 220107847 -0.91 9.5e-08 0.000013 8.9838 0.545429
cg21171625 DNALI1 1 38022607 -0.91 1.1e-07 0.000013 4.4322 0.642407
cg16068833 CD52 1 26644515 -0.9 1.3e-07 0.000013 7.4987 0.745924
cg11600161 TBC1D10C 11 67171585 -0.9 1.4e-07 0.000013 6.0011 0.598938
cg01448132 LAT 16 28996533 -0.9 1.4e-07 0.000013 7.3890 0.575771
cg23612220 TNFAIP8L2 1 151129298 -0.9 1.4e-07 0.000013 5.8562 0.801206
cg02358862 CORO1A 16 30197211 -0.9 1.4e-07 0.000013 9.5496 0.735688
cg07380416 CD6 11 60739172 -0.9 1.5e-07 0.000013 6.6945 0.784051
cg15551881 TRAF1 9 123688715 -0.89 1.7e-07 0.000013 9.3772 0.732779
cg23732024 LY96 8 74903801 -0.89 1.8e-07 0.000013 6.4358 0.596943
cg21249754 PTPN6 12 7060206 -0.89 2e-07 0.000013 8.6313 0.753489
cg21999229 LTA 6 31540014 -0.89 2e-07 0.000013 3.2103 0.877995
cg19540471 SEMA6A 5 115907550 -0.89 2e-07 0.000013 10.4770 0.674796
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-NF1_Any_Mutants/3155595/0.GDAC_MethylationPreprocess.Finished/SKCM-NF1_Any_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-NF1_Any_Mutants/3154951/SKCM-NF1_Any_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.