One can gauge the clinical impact of free radical overload and improper oxidative modifications of proteins by examining the myriad of molecular malfunctions and signal misfiring caused by excessive ROS/RNS, which ultimately result in cell death or neoplasia due to the inactivation or hyperactivation of various kinases/phosphatases such as the phosphatase and tensin homolog (PTEN). This evidence concerns the gene PTEN and neoplasm.