CDO1 and lung cancer: In the eleven lung cancer-specific methylation markers (CDO1, GSHR, HOXA11, HOXB4-1, HOXB4-2, HOXB4-3, HOXB4-4, LHX9, MIR196A1, PTGER4-1, and PTGER4-2), 21 CpG sites (cg09076431, cg07852825, cg15987088, cg08516516, cg11036833, cg23180938, cg27071460, cg15760840, cg14458834, cg21546671, cg08089301, cg09194159, cg14345497, cg02422694, cg07015911, cg12806763, cg19081437, cg24114154, cg26327071, cg21460081, and cg01452847) were found in the TCGA database.