FMO5 and cancer: For AML and some ALL cells, most ROS production could be counted (about 60%) by NOX (NADPH oxidase) activity 58 and, since some cancer cells have an impaired antioxidant system, the ROS overproduced by ultrasound has a more negative effect on viability leading to unbalance oxidative status and high oxidative stress causing caspases activation, mitochondrial damage, and finally late apoptosis.