In line with this, GSEA results were in general also validated: in LUAD, we also observed epithelial-specific hypermethylation at transcription factors and PRC2 targets, epithelial-specific hypomethylation associated with a poor outcome signature in lung cancer, and endothelial-specific differential methylation at SMAD2/3 targets (Additional file 1: SI Fig. S10). This evidence concerns the gene SMAD2 and lung cancer.