In this section, we will perform the same analysis performed using ELMER, but instead of doing it programmatically we will use TCGAbiolinksGUI (Silva et al. 2017).
First we will launch the TCGAbiolinksGUI.
library(TCGAbiolinksGUI)
TCGAbiolinksGUI()
Please download this two objects:
To create the MultiAssayExperiment object go to Integrative analysis/ELMER/Create input data
.
Select the DNA methylation object previously downloaded.
Select the gene expression object previously downloaded.
Fill the field Save as:
and click on Create MAE object.
The object will be created.
To perform ELMER analysis go to Integrative analysis/ELMER/Analysis
.
Select the MAE data created in the previous section.
Select the groups that will be analysed: Primary solid Tumor and Solid Tissue Normal.
We will identify probes that are hypomethylated in Primary solid Tumor compared to Solid Tissue Normal.
For the significant differently methylated probes identified before we will correlated with the 20 nearest genes. Change the value of the field Number of permutations
to 100
, Raw P-value cut-off
to 0.05
and Empirical P value cut-off
to 0.01
.
There will be no changes in the step 3.
There will be no changes in the step 4.
Click on Run the analysis
.
If the analysis identified significant regulatory TF the results will be saved into an R object.
To visualize the results go to Integrative analysis/ELMER/Visualize results
.
Click on Select results
and select the object created on the previous section.
You will be able to visualize the correlation between DNA methyation levels and gene expression selecting a pair of gene and probe.
A probe and its near genes.