We have performed a genome wide methylation screen (Infinium HumanMethylation450 BeadChip) in three lung cancer cell lines (A549, A427, H322) and normal human bronchial epithelial cells (NHBEC) and found a hypermethylation of ABCB4 at six CpG sites in its CpG island promoter in A549, A427 and H322 compared to NHBEC (21%, 48% and 88% compared to 7%, respectively). Here, ABCB4 is linked to lung cancer.