Nakano et al. have investigated the methylation status of the ABCG2 promoter in non-small cell lung cancer (NSCLC) (NCI-H358, NCI-H441, NCI-H460) and small cell lung cancer (SCLC) (NCI-H69, PC-6) cell lines [145]. This evidence concerns the gene ABCG2 and small cell lung carcinoma.