In addition to being involved in cytokine and ROS production, as part of the NADPH oxidase complex, RAC is engaged in cell cycle progression, transformation, induction of actin polymerization, regulation of membrane ruffling, and adhesion of cells to the ECM or neighboring cells, thereby regulating movement, tissue morphogenesis, cancer initiation, and metastasis (229, 361). Here, FMO5 is linked to cancer.