Correlations between copy number and mRNAseq expression
Colorectal Adenocarcinoma (Primary solid tumor)
28 January 2016  |  analyses__2016_01_28
Maintainer Information
Citation Information
Maintained by TCGA GDAC Team (Broad Institute/MD Anderson Cancer Center/Harvard Medical School)
Cite as Broad Institute TCGA Genome Data Analysis Center (2016): Correlations between copy number and mRNAseq expression. Broad Institute of MIT and Harvard. doi:10.7908/C1CC102J
Overview
Introduction

A TCGA sample is profiled to detect the copy number variations and expressions of genes. This pipeline attempts to correlate copy number and Rnaseq data of genes across samples to determine if the copy number variations also result in differential expressions. This report contains the calculated correlation coefficients based on measurements of genomic copy number (log2) values and RNAseq expression of the corresponding feature across patients. High positive/low negative correlation coefficients indicate that genomic alterations result in differences in the expressions of mRNAseq the genomic regions transcribe.

Summary

The correlation coefficients in 10, 20, 30, 40, 50, 60, 70, 80, 90 percentiles are 745.5, 1336, 1860, 2445, 3019, 3567, 4095.5, 4676, 5397, respectively.

Results
Correlation results

Number of genes and samples used for the calculation are shown in Table 1. Figure 1 shows the distribution of calculated correlation coefficients and quantile-quantile plot of the calculated correlation coefficients against a normal distribution. Table 2 shows the top 20 features ordered by the value of correlation coefficients.

Table 1.  Counts of mRNAseq and number of samples in copy number and expression data sets and common to both

Category Copy number Expression Common
Sample 616 623 613
Genes 24776 18041 15416

Figure 1.  Summary figures. Left: histogram showing the distribution of the calculated correlations across samples for all Genes. Right: QQ plot of the calculated correlations across samples. The QQ plot is used to plot the quantiles of the calculated correlation coefficients against that derived from a normal distribution. Points deviating from the blue line indicate deviation from normality.

Table 2.  Get Full Table Top 20 features (defined by the feature column) ranked by correlation coefficients

Locus ID Gene Symbol Cytoband cor p-value q-value
9491 PSMF1 20p13 0.8827 0 0
5786 PTPRA 20p13 0.8654 0 0
91782 CHMP7 8p21.3 0.8588 0 0
55756 INTS9 8p21.1 0.8518 0 0
54915 YTHDF1 20q13.33 0.8495 0 0
55140 ELP3 8p21.1 0.8446 0 0
55968 NSFL1C 20p13 0.8444 0 0
57805 KIAA1967 8p21.3 0.842 0 0
25980 AAR2 20q11.23 0.8401 0 0
26133 TRPC4AP 20q11.22 0.8378 0 0
51507 RTFDC1 20q13.31 0.834 0 0
64412 GZF1 20p11.21 0.8238 0 0
9675 TTI1 20q11.23 0.8205 0 0
57136 APMAP 20p11.21 0.8199 0 0
128637 TBC1D20 20p13 0.8189 0 0
55174 INTS10 8p21.3 0.8181 0 0
55617 TASP1 20p12.1 0.8134 0 0
203069 R3HCC1 8p21.3 0.8133 0 0
51497 NELFCD 20q13.32 0.8118 0 0
23039 XPO7 8p21.3 0.81 0 0
Methods & Data
Input

Gene level (TCGA Level III) mRNAseq expression data and copy number data of corresponding gene derived by GISTIC pipelinePearson correlation coefficients were calculated for each pair of genes shared by the two data sets across all the samples that were common. The input file "COADREAD-TP.uncv2.mRNAseq_RSEM_normalized_log2.txt " is generated in the pipeline mRNAseq_Preprocess in the stddata run.

Correlation across sample

Pairwise correlations between the log2 copy numbers and expressions of each gene across samples were calculated using Pearson correlation.

Download Results

In addition to the links below, the full results of the analysis summarized in this report can also be downloaded programmatically using firehose_get, or interactively from either the Broad GDAC website or TCGA Data Coordination Center Portal.