Since the identification of tranylcypromine, multiple irreversible LSD1 inhibitors have been developed and have been investigated in various other tumor models, mostly hematological and small-cell lung cancer; these molecules include GSK-LSD1, ORY-1001, RN-1, IMG-7289, INCB059872, and ORY-2001 [142, 143, 145–148]. Here, KDM1A is linked to small cell lung carcinoma.