Figure 1.

Genomic organization of the PD-1 (PDCD1) gene and location of the analyzed Infinium HumanMethylation450 BeadChip probes. Gene organization is based on the Genome Reference Consortium Human Build 38 (GRCh38) which is illustrated using the Ensemble genome browser (http://www.ensembl.org). Shown are three transcript variants (PDCD1-001, PDCD1-002, PDCD1-003). The PDCD1-002 transcript is assumed to undergo non-sense mediated decay, a process which prevents the expression of erroneous or truncated proteins. The methylation specific beads analyzed in the TCGA cohort are located in the annotated promoter region upstream of a CTCF binding site. The assay performed in the University Hospital Bonn cohort is also depicted. The gene contains an enhancer element and a region of open chromatin. Percentage of CG content is depicted indicating a high CpG content throughout the whole gene (promoter and gene body).