SOX17, TAC1, CDO1, HOXA9 and ZFP42 were the 5 genes that were identified in the Cancer Genome Atlas (TCGA) with highly prevalent DNA methylation in lung squamous and adenocarcinoma, but not in normal lung tissue (Cancer Genome Atlas Research, 2012; Wrangle et al. 2014; Diaz-Lagares et al. 2016). Here, CDO1 is linked to adenocarcinoma.