KDM1A and lung cancer: Histone lysine-specific demethylase 1 (LSD1) is a highly conserved flavin adenine dinucleotide (FAD) dependent oxidative enzyme, the ability of expression of which has been discovered in a variety of tumor cells, including neuroblastoma, breast cancer, lung cancer, gastric cancer, acute myeloid leukemia, and so on [1,2,3,4,5].