The cell cycle is controlled by cyclin-dependent kinase (CDK) activity, and CDK7 inhibitors have been proven to be effective in cancer treatment.44 CDK7 is a key regulator of RNA polymerase II (RNA Pol II)-dependent transcription via the phosphorylation of RNA Pol II and CDK9.45 CDK7 is activated upon phosphorylation of T170, which is associated with cell growth,46 was reduced upon SP2509 treatment advocating the association between LSD1 and CDK7 phosphorylation. The gene discussed is CDK9; the disease is cancer.