GPX3 and cancer: [20], [21]. It has been reported that GPX3 catalyzes the reduction of hydrogen peroxide and lipid peroxides and is a major scavenger of ROS produced during normal metabolism or after oxidative insult [22], [23]. GPX3 is selectively expressed in normal human tissues, including the gastrointestinal tract. However, downregulation of GPX3 has been recently reported in multiple human cancers such as prostate, esophageal, and bladder cancer [24]–[26], suggesting its importance in human tumorigenesis.