Another major source of cellular ROS are NADPH oxidases, including NOX4, which has been implicated in another hallmark of ageing, namely senescence.[26, 27, 28] NOX4 may represent a possible therapeutic target to reduce ROS production in age‐associated diseases such as cardiovascular disease,[29] and to prevent the premature ageing phenotype seen in cancer survivors treated with radiotherapy.[30] The association between ROS production by NOX4 and ageing phenotypes provides further evidence of the importance of oxidative stress in ageing. The gene discussed is NOX4; the disease is cancer.