Fig. 1

Epigenetic and gene expression analyses of immune checkpoint molecules in human NSCLC and corresponding control tissues. HumanMethylation450k BeadChip data, obtained from 39 tumor tissues and their corresponding controls, identified multiple CpG loci differentially methylated in CTLA4 a and PDCD1 (PD1) b genes (FDR < 0.01, t test). For data validation bisulfite pyrosequencing c of an independent patient cohort (n = 20) was performed, confirming differential methylation of tumor tissues detected previously via HumanMethylation450k BeadChip d at selected loci (CTLA4: cg08460026 and cg26091609, PDCD1 (PD1): cg25798782). Heatmap.2 was utilized for hierarchical cluster analysis and data visualization. Blue bars on top of heatmaps: tumor-free lung tissue, yellow bars: tumor tissue. Transcriptome analyses of 18 patients showed elevated transcript expression of CTLA4 e PDCD1 (PD1) Transcriptome analyses of 18 patients showed elevated transcript expression of CTLA4 e PDCD1 (PD1) f and, to a lesser degree, CD274 (PD-L1) g in the tumor samples. Transcriptome data was analyzed via paired t test of quantile-normalized, relative gene expression values with p ≤ 0.05 (=*) regarded as significant