Thyroid Adenocarcinoma: Correlation between mRNA expression and DNA methylation
(follicular 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 = 73. Number of gene expression samples = 73. Number of methylation samples = 73.

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 = 73

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
cg23245485 SCNN1A 12 6484219 -0.91 0 0 9.6162 0.596919
cg07150145 PDZK1IP1 1 47656137 -0.91 0 0 NA 0.489324
cg02126235 SERPINA1 14 94855034 -0.87 0 0 11.6693 0.584449
cg15464148 LPAR5 12 6745057 -0.86 0 0 8.2517 0.425340
cg07262247 PDLIM4 5 131593730 -0.86 0 0 7.9525 0.637317
cg03585823 MT1F 16 56693070 -0.86 0 0 11.2993 0.598400
cg11763394 LOC654433 2 113992921 -0.85 0 0 3.9325 0.909653
cg00988350 GALE 1 24126048 -0.85 0 0 9.1084 0.499447
cg15413523 TCF7 5 133451625 -0.85 0 0 8.1559 0.598269
cg07114009 ZNF750 17 80797948 -0.85 0 0 7.2318 0.607215
cg00876266 CAPS 19 5915133 -0.85 0 0 9.6760 0.659132
cg10045881 CHI3L2 1 111770291 -0.84 0 0 7.6501 0.488647
cg24749672 BIN2 12 51718108 -0.83 0 0 5.5642 0.917948
cg03190661 TMC8 17 76126702 -0.83 0 0 7.5453 0.538426
cg01255894 GATA3 10 8099218 -0.83 0 0 6.7273 0.306532
cg21188037 MYO1G 7 45018658 -0.83 0 0 6.0928 0.782112
cg08686960 COX7A1 19 36642720 -0.83 0 0 8.0328 0.576356
cg02123091 HMGA2 12 66261320 -0.83 0 0 NA 0.776354
cg12649175 DPP4 2 162927003 -0.83 0 0 8.8910 0.590673
cg13394864 FAM178B 2 97563733 -0.83 0 0 NA 0.668897
cg24815934 ITGB2 21 46332181 -0.82 0 0 8.8627 0.796094
cg03625911 CHI3L1 1 203155737 -0.82 0 0 NA 0.468467
cg21163717 DOK2 8 21769903 -0.82 0 0 5.1944 0.876727
cg17243643 RDH5 12 56114269 -0.82 0 0 6.4646 0.638351
cg04472592 KRT80 12 52585786 -0.82 0 0 6.6316 0.446301
cg14397690 ANXA2 15 60688948 -0.81 0 0 12.1954 0.480703
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/THCA-follicular/2851542/0.GDAC_MethylationPreprocess.Finished/THCA-follicular.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/THCA-follicular/2851211/0.mRNAseq_preprocessor.Finished/THCA-follicular.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.