Among the NOX inhibitors, those that specifically restrain NOX4 activity gained particular interest in cancer research due to the multiple links between NOX4-derived ROS production and diverse aspects of tumor promotion, dissemination, therapy resistance, and that some of these effects were related to the modulation of the metabolic adaptive responses of tumor cells [21,22,27,29,36,211,212,213,214,215,216,217]. The gene discussed is NOX4; the disease is cancer.