G6PDH is the rate-limiting enzyme of the PPP, and acts as a guardian of cellular redox homeostasis by cooperating with NADPH oxidases (NOXs) and synergistically regulating the generation of ROS (Zhang et al., 2017a; Yang et al., 2018), which play critical roles in tumor development and progression (Liou and Storz, 2010). Here, FMO5 is linked to neoplasm.