However, ROS are also destructive on tumoral cells in higher concentration; Afzal et al. noted that paclitaxel, an established mitotic inhibitory drug [26], promotes ROS generation by enhancing the activity of NADPH oxidase NOX [25] with accumulation of ROS products outside the cells which provokes lethal damage to bystander cancer cells that have not been exposed to paclitaxel [26,27]. The gene discussed is FMO5; the disease is cancer.