While the loss of LSD1 caused increased levels of H3K4me1/me2, the inactivation of LSD1 in mouse ESCs, human teratocarcinoma PA1 cells, human colorectal carcinoma HCT116, and lung carcinoma H1299 cells led to the proteolytic downregulation of the methylated DNMT1, SOX2, and E2F1 proteins. The gene discussed is KDM1A; the disease is lung carcinoma.