Next, the human lung cancer cell lines A549 and H1299, in which OLIG1, BAHD1, and DMRTA1 are methylated and not expressed, were treated with 1 μM of 5-aza-2′-deoxy-cytidine (5-aza-dC) for 48 and 72 h. The gene discussed is OLIG1; the disease is lung cancer.