PTEN and cancer: Discovered in 1997 by two independent research groups,(55,56) the PTEN gene is a common deletion on chromosome 10.Monoallelic mutations are common in various types of cancer; however, homozygousPTEN mutations are frequently found in advanced cancers, such asendometrial cancer and glioblastoma.(57) Interestingly, PTEN is heavily regulated by variousgene regulation processes, such as RNA interference, methylation, acetylation,oxidation, and ubiquitination.