Comprehensive analyses of genome-wide methylation and RNA epigenetics identify prognostic biomarkers, regulating the tumor immune microenvironment in lung adenocarcinoma

The aim of our study was to identify a signature of immune-regulated molecules and reveal its prognostic role in lung adenocarcinoma (LUAD). We downloaded RNA-Sequencing data and DNA methylation data from the Gene Expression Omnibus (GEO) database. GEO2R was used to analyze differentially expressed mRNAs (DEmRNAs). we used "factoextra" R package to do the principal component analysis (PCA) of DEmRNAs. "Limma" R package was used to identify DEmRNAs, differentially expressed miRNAs (DEmiRNAs), differentially expressed lncRNAs (DElncRNAs) from The Cancer Genome Atlas (TCGA) database. Three R packages "org.Hs.eg.db", "clusterProfiler", "ggplot2″ were used to show enrichment results. Considering about methylation and mutation data, TEK and SOX17 mediated cancer signaling pathways. Through tumor-immune system interactions database (TISIDB) and Tumor Immune Estimation Resource (TIMER), higher methylated and lower expressed TEK may act as a prognostic marker, regulating the tumor immunity in LUAD. Through four databases (MEXPRESS, DNMIVD, MethSurv, Firehose), we further verified the methylation (P = 2.33e-23) and mutation about TEK. A signature of immune-associated TEK to predict survival of LUAD patients was validated. Prognostic, methylation, immune microenvironment analysis showed new light on potential novel therapeutic targets in LUAD.