Thyroid Adenocarcinoma: Correlation between mRNA expression and DNA methylation
(classical 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 = 169. Number of gene expression samples = 169. Number of methylation samples = 169.

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 = 169

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
cg09032544 CD247 1 167487295 -0.88 0 0 5.502 0.920385
cg11763394 LOC654433 2 113992921 -0.88 0 0 4.223 0.913804
cg09897970 C16orf54 16 29757344 -0.88 8.8e-55 1.1e-54 4.883 0.843218
cg24749672 BIN2 12 51718108 -0.87 0 0 6.565 0.874863
cg25651476 NLRP2 19 55476717 -0.86 0 0 6.302 0.559495
cg01681367 SPN 16 29676071 -0.86 0 0 7.161 0.858440
cg21163717 DOK2 8 21769903 -0.84 0 0 6.545 0.799613
cg22821300 RASGRF1 15 79296585 -0.84 0 0 NA 0.508328
cg07114009 ZNF750 17 80797948 -0.84 0 0 7.809 0.577358
cg05564251 SP140 2 231090640 -0.84 0 0 4.932 0.828141
cg25754958 PTPN7 1 202130692 -0.84 0 0 6.314 0.751782
cg19318380 KLK11 19 51529902 -0.83 0 0 NA 0.609696
cg08450017 CXCR6 3 45984838 -0.83 0 0 5.717 0.881247
cg19280572 LSP1 11 1873884 -0.82 0 0 8.697 0.778186
cg21188037 MYO1G 7 45018658 -0.82 0 0 9.068 0.482935
cg16280132 LTA 6 31540459 -0.82 0 0 NA 0.818723
cg24674703 CD5 11 60869960 -0.82 0 0 5.524 0.868330
cg13832290 SIT1 9 35649906 -0.82 0 0 4.104 0.898558
cg19901005 NAPSA 19 50869007 -0.82 0 0 7.121 0.780460
cg23887948 STRA6 15 74494854 -0.81 0 0 8.535 0.581323
cg07675031 SPI1 11 47399893 -0.81 0 0 8.125 0.902330
cg09153080 CD6 11 60739183 -0.81 0 0 6.168 0.810582
cg04232128 TMEM173 5 138861241 -0.81 0 0 10.386 0.529972
cg05959508 TRAF3IP3 1 209929512 -0.8 0 0 5.664 0.649611
cg23427348 CPE 4 166301256 -0.8 0 0 12.871 0.513594
cg12459932 RUNX3 1 25292018 -0.8 0 0 6.407 0.907557
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-classical/2851538/0.GDAC_MethylationPreprocess.Finished/THCA-classical.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-classical/2851210/0.mRNAseq_preprocessor.Finished/THCA-classical.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.