ATO affects the biological behavior of leukemia cells through a series of mechanisms in AML, including induction of cell cycle arrest, apoptosis, and autophagy; generation of reactive oxygen species and accumulation of intracellular hydrogen peroxide; release of cytochrome c and activation of caspases; inhibition of glutathione peroxidase; and promotion of differentiation and anti-angiogenesis [22–24]. The gene discussed is CYCS; the disease is leukemia.