Interestingly, a recent study showed that adipocytes promoted prostate cancer cell invasion through stimulation of expression of the pro‐oxidant enzyme, NADPH oxidase, and ROS production; however, inhibition of FAO had less of an inhibitory effect on prostate cancer cell invasion.[25] In contrast, inhibition of FAO substantially impeded breast cancer cell invasion in response to adipocytes,[8a] indicating that a distinct metabolic pathway via the FAO pathway is preferentially utilized in obesity‐associated breast tumor cells. Here, FMO5 is linked to obesity due to melanocortin 4 receptor deficiency.