PTEN and cancer: ROS can stimulate PI3K/protein kinase B (AKT) signaling through the oxidation of a cysteine thiol group on various phosphatases (e.g., PTEN, PTP1B, PP2A) and contribute to dysregulation in a wide range of human cancers (e.g., endometrial, breast, thyroid, and prostate cancers) [69,70].