Fig. 1
From: Bronchial biopsy specimen as a surrogate for DNA methylation analysis in inoperable lung cancer
Selection of lung cancer-specific methylation. a The quality of the 450K array was checked by analyzing measured values for predefined subsets of methylation levels (0, 33, 66, and 100%) that were prepared by mixing fully methylated and unmethylated human control DNA. The X- and Y-axes indicate β-values of CpGs and the density of CpGs corresponding to individual β-values, respectively. b, c Methylation levels identified by the 450K array were validated using pyrosequencing. Methylation levels at a randomly selected cg27364741 locus are higher in 450K array than in pyrosequencing. d The relationship between patient’s age and β-values from 450K array was analyzed using Spearman’s correlation coefficient in 42 normal tissues. Methylation levels at cg26354128 loci show a linear relationship to age. e Methylation levels of finally selected ten genes were compared according to histology. “Squamous” indicates squamous cell carcinoma. The color spectrum from green (0%) to yellow (30%) to red (100%) indicates the levels of DNA methylation. The X-axis indicates the identification number of lung tumor tissue (LTT)