NOX4 and melanoma: Additional evidence for the tumor-promoting role of NADPH oxidase NOX4 was offered by a study demonstrating NADPH oxidase NOX4 increased expression of cyclin-dependent kinase 1 (CDK1) and cell division cycle 25C/M-phase inducer phosphatase 3 (CDC25c), both of which promote cell cycling, anchorage-independent growth, and melanoma tumorigenesis in vivo (389).